Home

Dec - American Radio History

Contents

1. printed cir cuit panel size 6 x 3in Generous size Driver and Output Trans formers Output transformer tapped for 3 ohm and 16 ohm speakers Transistors GET114 or 81 Mullard ACI28D mike or speaker ONLY 8 6 P amp P 1 6 A stylishly finished and matched pair of AC128 o p 9 volt operation CRYSTAL MIKES High imp for desk or hand use monaural amplifier i Everything supplied wire battery clips solder eic High sensitivity 18 8 P amp P 1 6 with an output of D d Comprehensive easy to follow instructions and circuit HIGH IMPEDANCE CRYSTAL STICK MIKES 14 watts from 2 fe 5 diagram 2 6 Free with Kit All parts sold separately OUR PRICE 21 P amp P 1 6 EL84s in push pull a E SPECIAL PRICE 49 8 P amp P 3 HIGH IMPEDANCE DYNAMIC STICK MIKES Super reproduction Also ready built and tested 85 7 P amp P 3 High sensitivity 89 8 P amp P 2 6 of both music and speech with negli HONEYWELL MICROSWITCHES 8 P C O Push button gible hum Separate action Rating 250v AC at 15 amps Size approx inputs for mike and lb x x din 5 each P amp P 1 6 or more post free gram allow records Go Pen A and announcements SPECIAL OFFER PLESSEY TYPE 29 TWIN TUNING to follow each other Ee GANG 400pF 146pF Fitted with trimmers and Fully shrouded section wound output transformer to 5 1 integral slow motion Sui
2. 4I I MIIIMI LOW COST ELECTRONIC AND SCIENTIFIC EQUIPMENT AND COMPONENTS HIGH SPEED IM by Davis Wynn amp Andrews dial and pointer registers up to 100 and 4 BRAND NEW HIVAC NUMICATORS Fig size 16mm Cold cathode gas filled in Ine e digital dieplay tubes bard fe expectancy Minimum strik F A ing voltage 180V Side reading digit counter both Type XN 3 XN 7 XN 12 and manually re settable The drive to the XN 23 Specit ber clear or counter is by air inverse escapement so red Price 18 6 P 2 6 that there is no loading of the polnter mechanism when digita are changed 0l and adjustable pawls are unnecessary GIN l Coil resistance 100 ohms for nominal slectricsl in seconds voit operation but the device works without plugs or rellably from 20 volts at rates up to sockets No more 10 Impulses sec In circuit with a worries about danger thyratron or neostron counting rates ous live wires Now up to 100 impulses sec are possible you can make electrical connections Provided pulse width is restricted to safely in seconds with the revolutionary keep mean current to 100mA Brand new Keynector Cuts out plugs socketa new in ind vidually sealed boxes and saves time A hundred different amp P 7 6 uses In the home and a must for the LINEAR THYRISTOR CONTROLLED do it yourself enthusiast Only 46 6 plus p and p 5 Or send for a leaflet Hent DIM NENTRRAND NEW wave bridge c
3. Going Back continued from page 674 21 pi BROADCASTING i Early copy zm KDKA S Radio Times mission on September 19th 1921 After that stations were opening every few days and within a year over a hundred stations were regularly broadcasting and a million receivers had been sold Even before the opening of WBZ KDKA had broken ground with all sorts of transmissions On January 2nd 1921 a religious service was relayed from a local church on March 4th the inaugural address of the newly elected President Harding was read out on the station at the same time as the speech proper was being made in Washington On April 1ith the first sports commentary was carried a boxing match and on May 19th the first farm programme was started For the first six months programmes originated from the transmitter room there was little need for a studio as most programmes consisted of either gramophone records or were relays from outside points In May however regular live music was added to the schedule and although these at first took place in a small auditorium in the building room resonance proved so serious that they were trans ferred to a tent on top of the main building and it was not until October 3rd that the first proper studio was built Dr Frank Conrad however was a true innovator and having seen that the station was properly established he turned his interest to the short wave bands In conjunction with a few
4. Case History H 493 A turning point in my career you have almost doubled my standard of living Case History K 662 Mechanical A M S E Mcch Inst of Engincers Mechanical Eng Maintenance Eng Welding General Diesel Eng Sheet Metal Work Eng Inspection Eng Metallurgy C amp G Eng Crafts C amp G l abrication Draughtsmanship A M LE D Gen Draughtsmanship Die amp Press Tools Elec Draughtsmanship Tig amp Tool Design Design of Elec Machines Technical Drawing Building Electrical amp Electronic A M S E Elec C amp G Elec Eng General Elec Eng Iustallations amp Wiring Electrical Maths Electrical Science Computer Electronics Electronic Eng Radio amp Telecomms C amp G Telecomms C amp G Radio Servicing Radio Amateurs Exam Radio Operators Cert Radio amp TV Engineering Radio Servicing Practical Television TV Servicing Colour TV Practical Radio amp Electronics with kit WHICH SUBJECT WOULD INTEREST YOU Auto amp Aero A M I M I MAA IMI Diploma C amp G Auto Eng General Auto Eng Motor Mechanics A R B Certs Gen Aero Eng Management amp Production Computer Programming Inst of Marketing A C W A Works Management Work Study Production Eng Storckeeping Estimating Personnel Management Quality Control Electronic Data Processing Numerical Control Planning Engineering Martctials Handling Operational Rese
5. 2N4289 de 130 isle 100 3 9 Technicians Course Pembridge College diplo ANAND S 500 3 SO ay mas are awarded to successful students CERCIASRCHB EVO 2N4292 8 gone 11l BCL4a BCY38 Sie IN4001 and 26 SEPT N 28001 10j BFI94 Sulata Des PL add The way to getahead in this fast growing industry 58009 l0 6hFlo5 Sj 100 4 6 100 1 2 an industry that gives you many far reaching 28003 28004 28005 28012 28013 28017 28034 28036 9 6 BD1 4 9 6 14 25 20 18 12 6 25 BEN3000 5 RF115 BFrl154 BF158 BFI59 BF163 BF167 12 8 5 8 8j 12 8 5i 500 4 IN4005 2 6 500 1 6 500 lj ZENER DIODES 400 MW 5 BZY88 Range All Voltages opportunities is to enrol now Minimum en trance requirements Senior Cambridge or O L vel or equivalent in Mathematics and English 3 7 i 3 3v 33v 3 6 28320 9 BF173 28321 ei BFLAO 1N4006 1N4007 25 2 9 POCHE ME Ert ee ee 98392 7 6 BFIB81 800v 3 1000v 4 100 ae 28323 10 BF X30 2 10 ideo X 17 To The Pembridge College of Electronics 28324 12 6 BFX88 i 28512 28701 28702 OcI40 7i6 C 28735 We n vaa OC207 Mullard Please send without obligation details of the To Pu riens Eip AT7 2 AAYIP 6 RLYII ORP6O 500 3 500 4 tronics 9 6 8 8 M BFY20 BFYS50 BFYB any one type Dept PW17 34a Hereford Ro
6. CHASSIS in Aluminium Standard Sizes with Gusset Plates Sizes to fit Cases All 24 Walls s d s d s d 6 x3 6 6 10x7 10 3 14 x3 8 9 6 x4 6 9 12 x3 8 O I4 x9 17 3 8x3 7 9 12 x5 9 0 l16 x6 12 9 8 x6 9 3 127 x8 12 9 16 x10 19 0 Chassis Post 3s Od per order Discounts available on quantities E R NICHOLLS Manufacturer of Electronic Instrument Cases 46 LOWFIELD ROAD STOCKPORT CHESHIRE Tel 061 480 2179 ALEOL Printed circuit boards for Practical Wireless and Practical Electronics pro jects from September 1970 All boards are roller tinned drilled and have the circuit layout printed in white S A E for list including this month s projects MICROBOARD just 1 25 ins by 0 9 ins Holds a single DIL 14 or 16 leads ideal for experiments with logic devices 2i plus S A E ALBOL ELECTRONIC amp MECHANICAL PRODUCTS LTD 2 Vine Lane Tooley St London S E 1 Tel 01 407 4214 EX GOVT COMMUNICATIONS RE CEIVERS calibrators signal generators components etc with money back guaran tee SAE list Callers welcome please phone first P R Golledge G3EDW Glen Tor Torrington Devon STD 08 052 2411 BRAND NEW ELECTROLYTICS 15 16V 0 5 1 2 5 10 20 30 40 50 100 mfds 9d E 2 series 5 6 resistors Carbon Film IW IQ to IMQ iSd Wirewound 5W 150 to ISKQ 10d postage 1 The C R Supply Co 127 Chesterfield Rd Sheffield 8
7. TEI035 RECOMMENDED STEREO PHONES 39 6 UNBEATABLE VALUE BUILD THIS VHF FM TUNER 5 MULLARD TRANSISTORS 300 kc s BANDWIDTH PRINTED CIRCUIT HIGH FIDELITY REPRODUC TION MONO AND STEREO A popular VHF FM Tuner for quality and reception of mono and stereo There is no doubt about it VHF FM gives the REAL sound All parts sold separately PARTS TOTAL COST 6 19 6 p p 3 6 DECODER 5 19 6 FOR STEREO p p 3I ASK FOR BROCHURE No 3 Se E New printed Gecutts desien eh futi BUILD power output Fully tuneable on both MWILW bands 7 Mullard YOURSELF eransistores Fitted Sin speaker Roam filling power asy to build witi terrific results Two colour leather QUALITY cloth cabinet with silvered front All RADIO local and continental stations Complete detailed instructions Total cost 6 19 6 p p 6 6 SINCLAIR Z30 75 each stereo 60 8 10 0 PZ5 79 6 EQUIPMENT P26 6 19 6 Z50 5 9 6 PZ8 5 19 6 2 30 0 PZ5 ily 23 10 SPECIAL OFFER 220 19 WHEN IN LONDON visit the new Disco Centre at 354 and component shop at 356 Edgware Road W 2 Ask for Leaflet No I AFIO05 50k v multimeter illus price 8 10 p p 3 6 leather case 28 6 200H 20k v multimeter price 3 17 6 p p 3 case 12 6 TE20D RF Generator illus price 15 p p 7 6 a TE22D Matching Audjo Generator price 17 p p 7 6 TE65 Valve Voltmeter price 17
8. at the height of the holiday season Henry s absence from the August issue was nothing to do with this That was a different matter What our Editor that mean and scrimping curmudgeon of a IE will not have escaped the ahem sorry what his High ness calls the exigencies of publication space Well he knows what he means So to avoid another omission of this column Henry is squatting atop a high mountain seeking inspira tion The deadline happens to come smack in the middle of our annual fortnight already curtailed to ten days by some last minute panics in the workshop A local Education Authority decided that the best time to wire out a dere lict class room for visual aids and audio reinforcement was while the pupils were under the feet of the parents rather than the teachers But eventually the job was sorted out and the kiddiwinkies will be able to Watch with E send zb Squatting atop a high mountain 670 Teacher when the term comes around again And Mrs Henry finally stopped huffing with im patience went back to make sure the gas was turned off col lected yet another piece of lug gage that we simply could not do without and the Henries salled off into the wild blue yonder Well wild grey actually for the vac was spent in Snowdonia and you may have read about the gales that uprooted venerable druidic trees and dismasted the weekender s small boats around the middle o
9. 74 19 135 0 28 0 47 45 10 49 17 79 17 95 0 129 0 31 17 129 1 127 4 145 19 162 3 62 17 80 9 94 5 77 9 OPEN ALL DAY SATURDAYS FIRST CLASS REPAIR SERVICE UP TO 15 DISCOUNT ON LP RECORDS SEND FOR LISTS Cave s Cash Price 27 5 46 19 42 10 48 15 52 0 58 10 52 19 59 10 89 13 69 12 52 10 59 19 119 18 75 15 92 11 29 19 3 16 3 16 4 3 8 10 5 2 4 5 5 16 5 2 2 15 3 18 4 5 8 10 22 19 23 10 37 19 52 10 21 19 3 19 47 19 19 19 19 19 9o00000000000000000000000000000000000000090000 ooo0000000000000000000000000000000000000000000o00o The Bell amp Howell range of loudspeakers from Acoustic Research of America Special Prices on 32 0 0 27 4 0 83 0 O 5311 0 application B amp W70Mon Celestion 10 s i 13910 0 118 11 0 21 13 9 18 10 0 Celestion 15 Celestion 25 we Goodmans Magister pe Magnum K Mezzo 2 Wainut Mezzo 2 Teak sx Mambo eu s 3005 Minister ai Mezzo 3 is i b Kef Cresta di List Price 29 0 59 17 57 0 40 2 30 18 30 18 22 6 Worth 25 0 Price on application Price on application 3 22 Kef Celeste Mk 2 29 0 Kef Concorde 43 10 Kef Concerto 53 10 Kef Chorale a 34 16 EMI Richmond Worth 32 0 Jordan Watts Module 12 0 Jordan Watts Jumbo 19 16 Leak Mini Sandwich
10. Also 350 KIT 20W 7 10 0 Frequency range plus 8 p amp p 20 to 20 000Hz Also 150 KiT 10W 3 8 or 15 ohms 50 plus 8 p amp p Normal price 12 10 0 SINCLAIR Project 60 SAVE nearly 5 Normal price 23 18 0d Designed for building into plus Fe 6666 f 2 plinths etc complete with 9 10j T 446 two Z30 Output stages carr 20 watt and power supply unit Send S A E for fuil technical brochure SINCLAIR 2000 AMPLIFIER SAVE 6gns Our price 23gns Magnetic cartridges imf CONDTONE artridges piamond 95 Fitted Diamond Styl siyH Ceramic list price 82 plus 2 6 p amp p Sensitivity 9TA B0mV 47 6 Today s value 6 9TAHC 55mV cm sec Stylus replacement rms minimum at 45 at plus can be carried out without removing 1 000Hz measured on 2 6 cartridge Fully guaranteed Decca SXL2057 p amp p Ronette 105 Stereo cartridge Sapphire 78 Diamond LP 25 2 6 p amp p J J FRANCIS WOOD GREEN LTD 123 ALEXANDRA ROAD HORNSEY LONDON N 8 Tel 01 888 1662 Guaranteed and Tested 24 HOUR SERVICE NEW VALVES IRS 5 6 DAC32 6 9 ECC81 3 6 EL84 4 9 PCF805 12 9 R19 6 3 185 4 3 DAF91 4 3 ECC82 4 EM34 18 0 PCF80611 U25 12 9 1T4 2 9 DAF96 7 ECC83 4 9 EY51 7j PCL82 8 9 U26 11 6 384 5 9 DF33 7 6 ECF80 5 9 EY86 6 8 PCL84 7 U191 12 3V4 6 6 DF91 2 9 ECF82 5 9 EZ80 4 3 PCL85 8 6 U
11. Circuit diagram and information on B44 Mk 2 transceiver with or without mods G Wheeler 45 Kings Way Billericay Essex information or manual for Hallicrafters Sky Champion and Canadian Mk 1 58 Tx Rx G Whitwell 90 Milverton Road Erdington Birmingham 23 information circuit handbook etc on the indicator unit type 300 Bell 82 St Catherine s Avenue Luton Beds circuit of Norde Mende 9050 radio D P Bourne 25 Green Street Georgetown Guyana South America v age diagram of the Verltone Vega unit M J Power 66 Oakdale Harrogate orkshire VES TERES sheet for an Ultra T491 radlo D Gregory 53 Wellinger Way Lelcester the addresses of the agents for Japanese transistor receivers and In particular Challenge agent Also details of connections to ampilfier and switching connec tions of the Minister Transistor Royal 410 tape recorder G Kingston Kruse Cottage Trevidland Liskeard Cornwall loan of theoretical circuit of Sound Sales amplifier type A Z serial A 50 75 and Ex unit C51 2 R V Flexman Horseshoe Cottage The Haven Billingshurst USsex ees ically Wir EIESS commentary by notice of our vigilant readers that there has been a gap in Henry s contributions lately Although these immortal lines will not be sullied with your marmalade until the jaunting season is over they are being written with the stub of a pen cil on the back of an hotel bill
12. Wired with mains cable and 5ft twin screened stereo cable 5 pin din plug 10 6 extra AP75 Complete with base and cover 25 plus 15 carriage Pack 234 Loudspeaker Socket 6j Ready made Leads 3 pin to 3 pin Din ios 12 6 3 pin to open end M 10 6 5 pin to 5 pin Din oe 16 5 pin to open end oe Ue 5 pin to 4 phono plugs Soe Bill All leads approx 6ft in length Post free by return PLINTH amp COVER 5 5 0 Unbeatable Value plus 10 p amp p Suitable for AT60 SP25 3000 2500 3500 Superb finish Spindle can be left in position with cover on Cover of neutral smoke tint perspex Also available for AP75 SL99 SL75 6 17 6 plus 10 carr d Replacement Stereo DIAMOND STYLI CATIA d 1 4 T9 EV26 GC8 5 each others on request p amp p 1 6 Countdown SPEAKER Teak Cabinet 12 insurance amp carr 7 6 A speaker of out standing specifi catlons and tech nical merit Solid teak cabinet size 14 x 10 x6 Originally designed for use with our Countdown stereo budget system but now available separately EMI low matched loudspeaker set 450 Our price T5 inc 5j p amp p 134 x 84 elliptical loud speaker and indepen dent high frequency units with associated crossover network Fre quency range 55 to 13000Hz The cone of the bass unit has a sur round designed for high travel giving freedom from distortion when operated at low frequencies
13. 3 Morse Telegraph Training Set 4 LC I Transistor Radio 5 Germanium 1 Transistor Radio 8 Record Player Amp n Continuity Tester 8 AF Signal Tracer 9 Radio Transmitter 10 Water Purity ester PRICE 3 10 0 2 TRANSISTOR SOLAR RADIO KIT Model R 126 Like all Roc Electronic Kits the R 126 uses reliable no solder connections to roi produce a complete 2 transistor radio in under 2 hours As well as battery operation the kit is supplied complete with a solar cell to provide power from the Sun or any strong light source PRICE 2 10 0 CRYSTAL RADIO KIT Model R 125 This easy to build Radio is based on the same circuit developed by Marconi for the very first radio transmission but uses a modern ferrite aerial for E maximum efficiency A perfect introduction to Radio Theory PRICE 1 10 0 5 WATT STEREO INTEGRATED AMPLIFIER CHASSIS Model R 123 Mounted on a heavy gauge chassis the fully iransistorised R 123 stereo amplifier is com pletely self contained even down to ganged volume and separate tone controls For a simple stereo amplifier ot excellent quality all Ms have to provide is the cabinet and control nobs SPECIFICATION Output 5W total 2 5W per channel Input sensitivity 600mV at 2 2Mohma A C 240v operation PRICE 4 19 0 AMPLIFIER Model R 133 Just slot in one of the many 8 track cartridge tapes available for a con tinuous programme of your favourite music A manual programme ov
14. 6Fl4 12 kBC81 8 8 PY33 18 6 6Fl 1l EBF80 g PY80 8 6 6F18 8 EBF83 8 6 PYS 6 6F23 15 6 EBF89 6 6 PY82 6 6H6 3 EBI21 19 PY83 7 6 6J4 9 6 kcs6 12 PY88 8 635 4 EC88 12 PY800 10 6J5GT 6 ECC40 14 PY801 10 636 3 6 gCCS4 8 U25 15 6J7 8 6 Bocas 6 6 U26 15 6K8G 6 ECC88 8 U50 6 L6GT 9 ECFs0 7 U52 8 UP PII el de ECF86 12 6 z 68AT 7 ECH 21 ive 282 8 68G7 6 EGH35 19 U301 11 6 68J7 X ECH42 18 U800 20 69K7 6 ECH81 65 6 UABC80 6 9 68L7 6 kcHss 8 6 UAF42 10 6 68N7 5 6 kcLS0 Q UBC41 9 6 68Q7 8 ECL82 6 6 UBC81 8 6U4 12 6 ECL83 12 6 UBF80 7 8 6v6G S gcrao 8 6 UBF89 7 6V6GT 86 8 EF37A 89 UCO84 9 9 6X4 Sj EF39 amp j UCCSS 8S 6X50 8 6 zF40 10 UCF80 10 6 6X5GT 5 6 EF41 12 6 UCH21 11 10Cc2 10j gp4 14 UCH42 13 10F1 18 prso 6 UCH81 6 6 10P13 ll peas 7y UCL82 7 10P14 20 gFao 6 6 UCL83 12 12AT6 5 ErFso 5 6 UF4l 10 12AT7 A4j poi 4jg UF80 7 6 12AU7 Bi roo q e UF85 8i 12AX7 8 EFia3 6 6 UF89 7 WAVE 6 EF184 7 ULAL 182 12BAG 6 6 xugo 8 UL84 6 6 12BE6 8 8 E134 10 6 UYA 8i 12BH7 6 6 EL33 17 6 UY80 6 19AQ6 6 6 gpai 11 VR106 30 20D1 9 EL42 11 6 5 20F2 15 eksi 10 V R150 30 E va EL84 5 8r EL85 8 opa ie m B ACA 20P4 20 EL95 7j LISTS 20P5 20 EMB0 8
15. 7R7 13 20L1 29 76 9 6 DF91 4 ECCS8 7 6 EMal 12 0 PCC84 6 8 PYG00 18 6 UCH42 10 6 0A2246 4 6 AFII7 5 BOIo 4j BF 4 NKT 213 5 OAD 3 j0A95 1 6 0C35 10 JOCT6 5 0C82D bj TRANSISTORS AF186 8 BCY32 10 BFY5s 3 6 NKT214 3 OAI0 8 6 OA200 1 60C36 12 6 0C77 8 JOC83 4 8 AF211 12 6 BcY33 4 BY100 4 NKTI217 8 0A70 2 0A202 g OC44 8 8 OC78 5 OCS4 4 9 2N2147 15 ACI T 7 6 AD149 10 AFzI2 15 BCY34 5 BY ll 7 NKT 74 4 OA71 2 OA210 6 OC45 3 OC78D 8 6 OCIO 5i 2Ns160 12 6 ACI28 8 lAD161 7 6 ASY53 4 BFl 7 5 BYOl3 5 NKT277 4 OA79 9 OCI6 10 OC70 2 8 0C8l 8 OCIIl 8j 2N2369A 4 ACYI7 6 AD162 7 ASZ21 8 6 BFI73 6 GET880 7 0 NKT40315 OA81 2 jOCI9 7 6 0C71 3 OCSID 4 OC200 7 6 2N2996 2 6 ACYIS 5 AFll4 5 BC107 82 6 BFX13 4 6 GJTM 7 6 NKT404 12 6 OA90 2 OC23 12 6 OC72 4 e OC82 5 OC201 9 6 QN3055 14 8 ACY39 11 AF115 5 9 BC108 2 6 BFX86 6 6 NKT713 5 OA91 1 6 0026 5 OC 5j OCP71 18 6 2N3819 7 lADI40 8 AFlI16 6 6 BCle9 2 6 BFY50 5 Tel 769 0199 1649 SEND S A E FOR LIST OF 3 000 TYPES Express Postage Insurance 9d per valve Renowned for Service H a S a i BM BLACKWOOD HALL WELLFIELD ROAD STREATHAM S W 16 Open to callers 9 a m 5 30 p m 6 000 types in stock send for lists S A E Closed Saturday 1 00 2 30 p m SUPER SENS
16. CORRIGENDA Mini Organ October 1970 In the circuit diagram Fig 1 the top end of the pre set potentiometer network should not be returned to the negative rail As shown the oscillator will function continuously The circuit is completed only through the stylus The Genetracer August 1970 The brackets at the top of Fig 1 should be amended to show RI to R4 inclusive as Generator and R5 C4 etc as Tracer The earthy end of D1 and VR2 should be shown connected to the positive line of the tracer i e SW2 and not that of the generator SW1 as shown Delete the second wire from the right hand tag of SWI Fig 2 To positive the necessary connection to the positive line is already pro vided by the lead from SWI to the output socket outer shield as shown in Fig 4 I C Stereo Equalisers and Mixers continued from page 641 If the circuits are used to drive an amplifier with a d c blocking capacitor at the input they can be connected directly to it However if they are to feed directly to a valve grid or a transistor base a blocking capacitor of O I4F or 1 F 3V respectively should be inserted The voltage ratings of the d c blocking capacitors at the inputs of the circuits must naturally be sufficient to withstand any d c level present in the input signal or the i c will be damaged POWER REQUIREMENTS If a d c supply of somewhat higher voltage than the i c requirements can be
17. How long does it take you to renew a fuse Time yourself when next one blows Then reckoning your time at 1 per hour see how quickly our resettable fuse auto circuit breaker will pay for EXTRACTOR FAN Cleans the air at the rate of 10 000 cubic ft per hour At the pull of a cord it ex tracts grease grime and cooking smella before they DOOR INTERCOM Know who ia calling and speak to them without leaving bed or chair Outfit comprises microphone with call push button connectors and master itself Price ouly L each or 11 per dozen specify 10 or 15 amp dirty decorations Suitable inter com Simply plugs to simply fit in place of switch for kitchens bathrooms gether Originally sold at 10 factories changing rooms Special snip price 49 6 pius 3 6 VARIAC CONTROLLERS ete it s so quiet it can With these you can vary the voltage applied to your circuit from zero to full mains without generating undue heat One obvious application therefore is to dim lighting We offer a range of these ex equipment but little used and in every way aa good as new Any not so will be exchanged or cash refunded 2 amp 4 19 6 5 amp 7 19 6 8 amp 12 19 6 10 amp 16 19 6 STANDARD WAFER SWITCHES amp t Standard Bize 1j wafer silver plated 5 amp Noot contact standard 1 spindle 2 long with locking Poles 2way 3way hardly be heard Compact 5 casing with 51 fan blades Suitable wherever it
18. NOSOLDERING JUST PLUG IN CONNECTORS ELECTRONIC ORGANS COMPLETE RANGE OF COMPONENTS IN STOCK FOR ALL PURPOSES MODERN ALL BRITISH TRANSIS TORISED DESIGNS AVAILABLE AS KITS OR READY BUILT VENEERED CABINETS FOR ALL MODELS 49 NOTE 61 NOTE SINGLE MANUAL DESIGNS ALSO TWO MANUAL 49 KITS AVAILABLE IN SECTIONS AS REQUIRED NEW PAX DISCOTHEQUE CENTRE AT 309 ALL WITHIN 100 YARDS 303 309 354 356 EDGWARE ROAD LONDON W 2
19. Parties or as a Baby Alarm Intercom Tele phone or Record Player Amplifier etc Attractive rexine covered cabinet size 12 x 9 x 4in with powerful 7 x 4in speaker and four transistor one watt power amplifier Uses PPS battery Brand new with famous maker s guarantee Only 75 P WEYRAD P50 TRANSISTOR CQILS RAW Ferrite Aerial 18 Spare Gores Ose PB0 1AC 8 Driver Trans LFDT4 LF P50 2CC 470 Printed Circuit PCA1 10 3rd LF P50 8CC J B Tuning Gang L P51 1 or P51 2 ME rid Booklet P50 8V 6 7 OPTI Mallard Ferrite 8 x jin 4 6 x din VOLUME CONT hm Coax 9a yd BR H AERIALITE AERAXIAL AIR SPACED 40 yd 28 60 yd 40 FRINGE LOW LOSS 2 J Ideal 625 lines yd Long spindles Midget Size 5 K ohms to 2 Meg LOG or LIN L S 3 P 5 STEREO L S 11 Edge 5K S P Tra WIRE WOUND 3 WA Small type with small knob Values 10 to 80 K 5 l LONG SPINDLE 8 l Carbon 30 K to 2 meg 10 OHMS to 100 K VEROBOARD 0 15 MATRIX 24 x Bin 3 8 24 x 3tin 8 2 34 x 811n 8 8 84 x bin 5 2 EDGE CONNECTORS 16 ab 5 24 way 7 6 PINS 36 per packet 8 4 FACE CUTTERS 7 6 S R B P Board 0 15 MATRIX iin wide 6d per lin wide 9d per 1 in Sin side 1 per lin up lo 17in undrilled win Board 10 x Sin 3 8 R mmn a 0 ee BLANK ALUMINIUM CHABAIB 18 s w g 2 in sides x Ain 6 11 x Bin 7 6 x Hin 9 6 18 x Bix 10 6 15 x 14in 15 9
20. at G d 2025 Auto Unit RPSE ri turi aoe e Eire Corttidge with diamond tip inth amp Cover as RP2C carr 9 6 15 Gns Other types available with Mag netic cartridges and with alternative design plinths LINEAR LIO HIGH FIDELITY 10W AMPLIFIER 10Gns with separate Pre amp Magnetic P U matching To clear SUPER 15 HIGH FIDELITY R S C BATTERY MAINS SOLID STATE AMPLIFIER CONVERSION UNITS Approx as Super 30 but single TYPE BM1 channel Complete kit with full constructional detaila and An ali dry bat point to point wiring diagrams tery eliminator Size 64 x 4 x 124 gns carr 12 6 Sin approx up OR FACTORY BUILT 15 Gne Completely replaces batteri lying 1 5y and 90 Carr 12 6 Terma Deposit 4 Gns p and 9 monthly payments 81 1 mains 200 250v 50c available Complete kit with diagram 59 9 or Total 18 3 9 Available in Teak or Afrormosia veneered housing 19gns Soconenien 00 9 R S C TA6 6 Watt HI FI SOLID STATE AMPLIFIER 200 2507 AC mains operated Frequency Re sponse 30 20 000 c p s 2UB Harmonic Distor tion 0 3 at 1 000 c p s Separate Bass and Treble litt and cut controls 3 input sockets for Mike Gram Radio or Tape Input selector switch Output for 3 15 ohm spkrs Max sensitivity bmV Output rating I H F M Fully enclosed enamelled case 91 x 24 x tn SMART silver finish facia plate 16 3 in and matching nobs Complete kit of parta with full wirin d diagrama and
21. mitters Tachometer Rain Alarm Testers Electronic Switches Amplifiers and even an Electronic Target Game As well as earphone speaker meter relay transformer solar cell buzzer etc etc the R 130 is supplied complete with a fitted hardwood case and clear detailed instructions for all 50 projects PRICE 7 19 0 20 PROJECT SOLAR ELECTRONIC KIT Model R 128 This ultra modern Project Kit is shaped for the space age Carried inside a transparent domed 4jin capsule the R 128 comes complete with a selt contained solar cell to power any one of 20 projects ranging from amp one transistor radio to a morse set complete with key and morse training code Supplied complete with easy to follow instructions and even the cement to assemble this unique electronic space capsule PRICE 4 10 0 2 OCTAVE ELECTRONIC ORGAN KIT Model R 129 Complete with a music book containing 10 easy to play songs the K 129 solid state organ kit covers 2 full octaves Slotting into a fitted hardwood case the top panel earries the key assemblies and all the components including the loudspeaker Like all Roc Electronic Kits every item is included down to the last nut and bolt so that the con structor can start assembly within minutes of opening the package PRICE 4 10 0 10 PROJECT INTEGRATED CIRCUIT KIT Model R 127 Using a robust Solid State Integrated circuit the R 127 kits will build any one of these projects 1 Germanium Radio 2 Test Oscillator
22. on average cancels out Q 8V dc Carrier input 3 9k 300mv rms 0 005yF Demodulated signal input AF output O tyF pF 8V dc 9 The MC1596G as an s s b demodulator or product detector A carrier input b f 0 level of 300mV r m s is optimum The composite s s b signal input may be between 5 and 500mV r m s One point of caution under certain circumstances depending on driving source impedances instability may occur If this is a problem the inputs should be shunted by suppressor networks made up of a 510 ohm resistor and a 10pF capacitor in series Notes It is also worth noting the wide bandwidth of the basic device the signal input is only 3dB down at 80MHz while the carrier response only drops at 300MHz The price of around 3 is something of an inhibition but if past experience with i c s is any guide it should drop rapidly particularly in view of the versatility of the device The unit is currently available from Motorola distributors in the U K including Jermyn Industries Vestry Estate Sevenoaks Kent Celdis Ltd 43 45 Milford Road Reading Berks u 647 LMOST everybody who regularly uses a tele A phone will know the frustration caused by a poorly connected call where words are heard faintly and have to be repeated making conversation difficult In addition use of the telephone can present a serious problem to the hard of hearing The unit described here is a co
23. 1 000V A C Volts 5 3 5 10 25 50 125 250 500 1 000V D Cur tent 25 50uA 2 5 6 250 500mA 5 10 amp Resis 2 K 10K 100K iMEG 10 MEG Q 90 to 85 db 219 10 0 amp Resistance 1k 10K 100K 1OMEG 100 MEG Q Decibels 10 to 49 db Plas tic Case with Carrying de Bize 74in x 6jin x 3jln 18 1 LAFAYETTE HA 800 SOLID STATE TEUR LAFAYETTE HA 600 SOLID STATE RECEIVER norte General coverage 150 400ke s 550 kc s 30mc s FET front end 2 mech filters detector variable B F O S Meter Bandspread 15 x 99 x 83 18 Ibs A C nr 12v D C Brand new instructions 246 Carr 10 RECEIVER 3 5 4 7 7 3 14 14 A x mc s Dual conver on 2 mech filters product detector vari amp ble BFO B Meter 100kc a calibrator 220 240v A C or 12v D C 15 x 93 Xx 8 18 tbs Brand new with inatruc tions 57 10 0 Carr Paid 100kc s Crystal 89 8 extra product noise limiter RF Oa 220 240 with LAFAYETTE RCA PF60 VHF FM COMMUNICATIONS RECEIVER ARS8D RECEIVER Solid Btate 152 174mc s Fully tune able or crystal controlled not supplied Built in Speaker Squelch and Volume Controls 220 240v A C or 12v D C Brand new with instructions 87 10 0 Carr 10 YAMABISHI VARIABLE VOLTAGE TRANSFORMERS Excellent quality Low price Immediate delivery Brand new 6 bands 535ke s 32me s Fully test
24. 15 to 15dB at 100Hz Butt tested and guaranteed 9 19 6 s LI Lj hs 3 Active Filter Unit pim T oo For use between Stereo 60 unit and two Z 30s or AR Z 50s the Active Filter Unit matches the Stereo 60 in one styling and is as easily mounted It is unique ir that the cut off frequencies are continuously variable E and as attenuation in the rejected band is rapid Fy Ged 12dB octave there is less loss of the wanted x signal than has previously been possible Amplitude and phase distortion are negligible The Sinclair A F U is suitable also for use with any other ampli fier system j Two stages of filtering are incorporated rumble IL variable from 28kHz to bkHz L F cut off 3d8 variable from 25Hz to 100Hz Filter slope both sections 12dB per octave Distortion at 1kHz 35V supply 0 02 6 atrated output high pass and scratch low pass Supply voltage 15 to 35V Current 3mA HF cut off 3dB 5 19 6 Built tested and guaranteed Power Supply Units The units below are designed specially for use with the Project 60 system of your choice Illustration shows PZ 5 power supply unit to left and PZ 8 for use with Z 50s to the right Use PZ 5 for normal Z 30 assemblies and PZ 6 where a stabilised supply is essential PZ 5 30 volts unstabilised 4 19 6 PZ 6 35 volts stabilised 7 19 6 PZ 8 45 volts stabilised Jess mains transformers 5 19 6 PZ 8 mains transformer 6 19 6
25. 24V at 1A and 6 3V at 144 12 6 2 6 250V at 50mA 22V at 1A and 6 3V at 15A 17 6 3 6 90V at 20mA and 1 4V at 250 mA 10 2 6 MONO GRAM CHASSIS 3 WATT 3 Wave band long med short Gram 200 250V AL Ferrite aerial Chassis 13 x 7 x Din Dnal 13 x 4in Double wound mains transformer 5 valves ECHSI EFS89 EBU81 ELS4 EZ80 Price 10 12 6 1 6 p amp p Output trans for 3 ohmn speaker NEW TAPE AMPLIFIER for 4 track E S R Deck TD2 Mains and output Trans 10 x 6 x 4 overall Rect ECC83 EL84 Mike and Gram Inputs 2 5 0 10 p amp p For 3 ohm speaker For 200 250V A C YOUR CAREER in RADIO amp ELECTRONICS Big opportunities and big money await the qualifled man in every field of Electronics today both in the U K and throughout the world We offer the finest home study training for all subjects in radio television etc especially for the CITY amp GUILDS EXAMS Technicians Certifi cates the Grad Brit LE R Exam the RADIO AMATEUR S LICENCE P M G Certificates the R T E B Servicing Certificates etc Also courses in Tele vision Transistors Radar Computers Servo mech anisms Mathematics and Practical Transistor Radio course with equipment We have OVER 20 YEARS experience in teaching radio subjects and an unbroken record of exam successes We are the only privately run British home study College specialising in electronics subjects only Fullest details wil
26. 250v A C Brand new with instructions 249 Carr Paid Full Range of other Trio Producta iu stock JR 5008E Amateur Receiver 265 0 0 JR 310 Amateur Recelver 77 10 0 TS 510 Amateur Transceiver 180 0 0 SP5D Matching Speaker 84 7 6 H84 Headphones 15 19 6 VOLTAGE STABILISER TRANSFORMER 8 180 260v input Output 230v Available 150w or 225w 12 10 0 Carr 5 EDDYSTONE VHF RECEIVERS Model 770R 19 165 Me s Excellent condition 150 INTERCOM BABY SITTER Vransistorised In ems ideal for lume office work hop ete 2 way buzzer call system For desk or wall 1u0unting Supplied vomplete with con necting wire bat tries instructions J station 59 6 P amp P 6 4 station 6 12 6 P x P 5 GW SMITH E AHIA ERANDIO J LTD Model MR 2305 5 amp 68 x 46 x 43mm 8 7 6 Model MR 2310 10 amp 90 x 68 x 60mm 11 19 6 Postage 2 6 All Mail Orders to 147 Church Street London W 2 01 262 6562 Trade supplied 3 LISLE STREET LONDON W C 2 Tel 01 437 8204 34 LISLE STREET LONDON W C 2 Tel 01 437 9155 311 EDGWARE ROAD LONDON W 2 Tel 01 262 0387 OPEN 9 6 MONDAY TO SATURDAY EDGWARE ROAD 12 DAY THURSDAY 621 by doing 1 OWN and HANDLE a complete range of present day ELECTRONIC PARTS and COMPONENTS m Ed VALVE EXPERIMENTS TRANSISTOR EXPERIMENTS AMPLIFIERS OSCILLATORS SIGNAL TRACER Shin M a new r e meth
27. 29 15 Tk Rswd Walnut 29 15 Leak Sandwich Walnut 45 10 Leak Sandwich Teak 45 10 Leak Sandwich Mahogany 45 10 Leads for above Lowther PM6 46 10 Lowther PM7 58 0 Philips RH491 23 0 Philips GL561 70 Enc 26 19 Philips RH481 11 0 Pioneer CS53 4113 Quad Electrostatic 66 0 Radon404 Worth 9 0 Radon Amethyst 13 17 Radon Sapphire 36 0 Rogers Ravengbrook we 4 10 Sansui SP30 31 8 Sansui SP200 63 0 Tannoy 12 Lancaster 56 5 Tannoy 15 Lancaster 63 5 Tannoy Richmond 1 12 Worth 59 0 Tannoy 111LZ 41 0 Thames Vee Gee Worth 18 18 Wharfedale Denton 19 0 Wharfedale Linton 22 10 Wharledale Dovedale 3 39 10 Wharfedale Melton 29 10 Wharfedale Rosedale Speaker Accessories Din Speaker Plugs Speaker Cable p yd TAPE RECORDERS Revox 1102 1104 2 Revox 1222 1224 Revox 1997 Dust Cover Ferrograph 713 ais Ferrograph 702 704 Ferrograph 722 724 Ferrograph Cover Akai 4000D Akai 1710L Akai 4000 Akai XSOOOL Akai X5000W ry Akal MIOL ri Tandberg 64X Philips 4302 Philips 4307 Philips 4308 Philips 4404 Philips 4407 Philips 4408 Philips 2502 Philips 2200 Philips EL3302 Philips 2400 Philips 2400 inc Speakers Philips 2401 Philips 2401 inc Speakers Philips N2202 Philips N2602 Car Stereo Cassette Player Sanyo Cassette Grundig TK120 Grundig TK124 Gr
28. 3524G 0 30 3525GT 0 40 50A5 0 70 eesepcsssesossso 50B5 0 45 50C5 0 40 50CD6G1 65 DK40 0 55 50L6GTO 50 DK92 0 50 85A2 0 40 DK96 90AV 2 50 DL96 90C1 DM160 90CV DY86 807 DY87 812A DY802 813 ES5L 866A E88CC 5642 E130L 6080 E180F 6146 EABC80 6146B EAF42 6360 EBC33 6939 EBC41 7199 EBC81 7360 EBF80 1586 EBF83 1895 EBF89 9002 EC53 9003 EC86 AZ1 EC88 EC90 AZ31 EOI ODUR EC93 0 CBL31 EC8010 2 25 CY31 ECC40 0 80 SYNCHROSCOPE TYPE C1 5 DAF96 0 42 DF96 042 ECC81 ECC82 ECC83 ECC84 ECC85 ECC88 ECC89 ECC91 0 ECC189 0 60 ECF80 0 35 ECF82 0 85 ECF83 0 75 ECF86 0 65 ECF8041 50 ECH42 0 70 ECH81 0 30 ECH83 ECH84 ECL80 ECL81 ECL82 ECL83 ECL84 ECL86 gt w o BNS 6BNG 6BQ5 6BR8 6BS7 6BWB 6BW7 6BX6 6HZ6 604 605CT 6CA4d 8CAT 6CHB6G 6CD6GA 1 15 0 50 0 55 0 50 0 83 0 65 0 45 0 75 0 48 0 63 eo ee o oc e PS w eeececers BSEEDEESSBESSSEBEBEBG e c e eeesssss x ga bo ba bo Ssones Bom Bow En ia m to co co go SSSSSSse 0 45 0 40 0 45 0 40 0 40 0 60 0 65 0 40 0 40 e at ai ia P U4G U4GB 5V4G 6Y3GT 523 5Z4Q 6 30L2 6AB4 SAFA4A 6AGT 6AH6 6AJ8 BAKS 6AK6 6AL3 6AL5 6AM5 6AM6G 6AQ5 6AQ6 Il AARSCGANABASSS b Go Go ie me eoeeor s perocooes peeresssssss S ZESS55558 coo oOoocomqm oo 892325 esorressss Ro 8CGT 6CH6 6CL6 CWA4 6CY7 bD3 6DCH 6DK6G 6DQ6B 6DS4 0 75 GRAS 0 58 6KH7 0 30 To 5
29. 8 DC current ranges 601A to 1 54 6 AC current ranges 0 6 to 1 5A 9 DC and AC voltage ranges 1 5 500V Resist ance ranges 0 5 500k Q Accuracy 1 5 DC and 2 5 AC Mirror scale 10 10 0 nd MINIATURE 1 IN CATHODE RAY TUBE TYPE DH3 01 1CP1 1CP31 63v heater Anode voltage 500v Sensitivity Y plates 45v cin X plates 52v cm typical Y plates suitable for assymrmetrical deflection Green face medium persistence PRICE 6 0 0 p p 0 26 2N2646 2N 905 2N2923 2N2924 2N7926 2N3053 2N3055 2N3133 INTEGRATED CIRCUIT AMPLIFIERS e eoeoo do CA3005 RF amplifier 100mc s bandwidth CA3012 Wide Band Amplifier for IF applications CA3020 550mW Audio Amplifier CA3036 Two super alpha pairs for stereo pick up systems vr CA3052 Latest addition amplifier PA222 1 2 watt Audio Amplifier PA234 1 watt Audio Amplifier PA237 2 watts Audio Amplifier MC1709G G P operational Amplifier TAA263 3 stage direct coupled Amplifier TAA293 3 stage direct coupled Amplifier a AE CARTRIDGE TYPE HS838 EHT RECTIFIER 10 000p i v Rectified current 350mA mat Surge current 30 Amps PRICE 7 00 ooo 2N3395 2N3402 2N3403 2N3404 2N3414 2N3415 2N3416 2N3417 2N3702 2N3703 2N3704 to RCA range Four in one OUR NEW 1970 1971 CATALOGUE IS NOW READY AND AVAILABLE FREE OF CHARGE PLEASE SEND QUARTO STAMPED AND ADDRESSED ENVELOPE FOR THIS VALUABLE SOURCE OF 2N3707 2N3709 2N3710 2N3819 2N3906 28002
30. 80 T 6iDF9c 7 6 ECFS82 6 6 ESUIS0 20 POCIS9 10 8 PY80l 9 6 UCLSD 7 6 6BR7 17 K7G 9BW6 7 20A8 5 8 85A9 7 8 DH77 4 9 ECH21 12 6 EYol 7 6 PCF80 6 9 R2 7 6 UCLS3 11 6 147 7 9 6BR3 12 0 6K7GT 4 6 10Cl 20 25L6GT 7 150B2 11 6 DK32 7 9 ECH35 11 6 EY86 7 PCF82 6 6 R19 7 9 UF41 10 6 1D5 7 66B87 25 6K8 9 9 1oCo 12 6 25Yo 6 150C4 9 6 DK91 6 ECH42 19 EZ3 6 PCF84 8 RG5 500 80 UF89 7 8 185 7 6BW6 14 6 6K8M 11 6 10FI 14 9 2024 6 3 801 9 6e DK92 9 ECH81 5 8 EZ40 9 PCF86 9 8130 40 UL4l 12 ILD5 6 6BW7 13 6K8G 3 l0F3 18 2525 8 807 9i DK96 7 9 ECH83 S 6 EZ4l 89 6 PCFS0l 9 9 SP4 g UL84 7l INSGT 8 604 5 6K8GT 7 I0F9 10 6 2576 8 6 8I3USA DL65 95j ECL80 7 EZ80 5 6 PCF802 9 9 SP41 6 6 UMSO 5 6 IRS e 6CaG 5 6K95 15 I0F18 8 28D 9 3 120 DL9 6 8 ECL82 7 EZ8 5 6 PCF805 15 SP6l 6 6 UU6 Bl 184 5 6 6C6 3 9 6L1 12 10L1 8 30C 6 9 813 5 DL93 4 ECL83 10 3 GY501 15 PCF806 13 STV280 80 UU7 8l 185 4 8 6C amp G 6 6L6G 7 8 10LDII 10 6 30Clo 15 866A 15 DL94 6 9 ECL86 89 GZ30 10 PCF808 15 6 95 UU8 2l IT4 4j 6CD6G 94 6L18 6 10PI3 19 6 30Cl7 16 954 63 DL9 7 9 ECLL80040 QZ32 10j PCLS2 7 9 SU25 19 6 UU9 8 8 3A4 4j ecHe 7 6 607G 8 11E3 70 30CI8 15 1625 6 6 DLo 7 8 EF9 20 GZ34 11 PCLS3 10 8 8U2150 12 868 UY21 9 8 304 7 9 6CW4 19 6 6Q7GT 8 6 I2AT6 4 D S0Fo 17 4022AR 67 DM70 6 EF37A
31. A RANGE OF SOLDERS IN HANDY DISPENSERS Pi ny REF ALLOY SWG 4A 60 40 18 aji ull Savbit 18 3 ted 18 60 40 22 4j Recommended Price E Y X Feom Electrical and Hardware sheps unobtainable write to Multicore Solders Ltd Hemel Hempstead Herts TYPE 13A DOUBLE BEAM OSEILLOSCOPES An excellent general pur pose D B oscilloscope T B 2 cps 750 Ke s Bandwidth 5 5 Mcjs Sensitivity 33mV CM Operating voltage 0 110 200 250V A C Supplied in excelent working con dition 822 10 0 Carriage 30 AVO CT471A MULTIMETER Battery operated fully tranaistorised Bensitivity 100mQ v Measures AC DC Voltages 12mV to 1 200v AC DC Current 12uA to 1 2 Amp Resistance 12 ohm to 120 mQ HF VHF UHF Voltage with multiplier 4v to 400v up to 50 Mc s 40mV to 4v up to 1 000 Mejs Offered in perfect condition 55 each Carr 10 CRYSTAL CALIBRATORS NO 10 Small portable erystai controlled wavemeter Size 7x TW X din Frequency range 500 Kc s 10 Mc s up to 30 Mejs on harmonica Calibrated dial Power require ments 300V D C Mm and 12V D C 0 3A Excellent condition 89 6 Carr 7 6 CLASS D WAVEMETERS A crystal controlled hetero dyne frequency meter covering 1 7 8 Meja Operation on 6 volta D C Ideal for amateur use Available in good used con dition 5 19 6 Carr 7 6 Or brand new with acces sories 7 10 6 C
32. ACI67 5 GET882 4 6 0C29 10 0C202 46 P 1jA 4 6 ACZ17 10 8 GETS886 4 6 0C35 8 6 2G240 40 2202 GA P D AD149 10 6 NK216 7 OC44 2 9 26302 3 6 4j AF115 8 j NKT279A 3 OC45 2 8 2N1302 8 6 GET120 with AF116 8 8 G D OC71 2 8 2N1306 4 6 Ht 8k amp AFI17 4 NKT463 6 8 0C72 2 8 28303 7 6 Wshr 4 6 BC108 3 6 P N P 0C73 2 8 T2040 5 CR6051 50V BFY18 4 6 OA5 1 6 OC74 2 8 VHF 6A Cond BFY61 4 OA10 1 6 OC75 2 8 TK20 1 Rectr 8 8 BSY18 8 8 OA47 1 9 OC76 2 8 TK22C 1 6 CRYSTAL DI BSY26 8 6 OA81 1 6 OCBl 2 6 Gen Purpose ODES SIX for BSY28 8 8 OA85 1 6 OCBID 2 6 TK5023 2 2 6 Up to six BSY29 3 6 OA95 1 8 OC82D 2 8 XA701 8 6 packets of 6 BSY65 8 6 OA209 4j 0C139 5i tor 1j WITH 4LEADS Charges Up to one dozen can be assorted 1 Over 12 charges paid D R s BYZ10 TEN AMP TWENTY THIRTY AMP BY100 800piv 1200piv 7 SERIES AM SERIES SERINE 2 10 each THYRISTORS 50 piv 10 50 piv 9 6 100 piv 12 6 SIX AMP SERIES FIVE AMP 100 piv 12 6 500 piv 18 6 400plv 85 BYZ13 300piv SERIES 800 piv 20 1600 piv 88 6 4 100 piv 7 8 pes up to 3 tor 1 3 to 11 1 6 12and i BYZI2 600piv 200 piv 9 arges up to 3 for 1 3 to 6 12 and over patd 5j 300 piv 10 6 Orders received after Nov 12th will not be despatched BYZ11 900piv 400 piv 12 6 until Nov 23rd nor will any mail be dealt with 6 800 piv 25 between these dates l i ELECTRO
33. ARTICLES AND FEATURES Don t miss your copy of the January issue of Practical Wireless on sale 4th December price 3s 6d SANI m A At MONTHLY NEWS FOR DX LISTENERS The first report this month comes from regular contributor C R S Stacey of Tunbridge Wells who used his Lafayette HA 700 receiver and Joystick antenna to hear 9665 R Trans Europe ident in German at 1955 9705 R Voice of the Gospel from 1815 to 1850 15410 VOA Tinang in Chinese from 1611 to 1659 Ian Howes of Lowestoft used his Unica 30 receiver with a TV aerial to send in an excellent first report which included 4850 Mauritania noted at 2210 4900 Radio Juventud Venezuela at 2240 4940 R Abidjan Ivory Coast at 2330 4967 5 Radio Kuwait noted at 2000 11805 Radio Globo Brazil at 2220 11925 Radio Bandeirantes Brazil at 0030 12175 Radio Tehran Iran at 2000 15245 Radio Kinshasa Congo noted at 2240 15410 VOA Philippines at 1445 Robert Cork of Basingstoke has built the PW modular short wave receiver and connected it to a 15 foot antenna with the following results nei Radio New Zealand to Pacific Islands at 11672 Radio Pakistan noted at 2005 ease CBC Radio Canada news in English at pate Voice of Nigeria news and comment at 11750 BBC Far East relay Tebrau s on at 0900 John Trewick of London Colney has sent in another report which contained 6540 Radio Pyongyang North Korea at 1930 9715 Radio Nederland Bonaire at 0800 15330
34. COMPLETE RANGE of receivers by Trio Lafayette Hallicrafters etc Chassis panels cabinets S a e for lists Stephens James Ltd 70 Priory Road Liverpool 4 Tel 051 263 7829 RECEIVERS amp COMPONENTS continued AUDIO 1 8 WATT AMPLIFIER Ready built tested and guaranteed Very attractive Cabinet in black leatherette with light grey front size 10 x 4 x 4 Fitted large speaker Jack Socket and Volume Control Many uses eg Radio Kit Amplifier Intercom Record Player Public Address or even Crystal Set Amplifier OUR PRICE ONLY 87 P amp P 4 6d EXTENSION SPEAKER CABINET The same Cabinet that houses our Amplifier ONLY 28 P amp P 3 Or with fitted Speaker 34 P amp P 3 6d NEW MODEL V H F KIT MK2 Our latest Kit improved design and performance plus extra Amplifier Stage receives Aircraft Amateurs Mobile Radio 2 3 4 etc This novel little set will give you endless hours of pleasure and can be built in one evening Powered by 9 Volt Battery complete with easy to follow instructions and built in Jack Socket for use with Earphones or Amplifier Only 68 P amp P Free U K only MAY FLOWER 5 Wave Band Short Wave Kit g t As illustated above our all wave band one valye easy to build kit Complete with one short wave and one medium wave plug in coil Extra coils available at 7 each Price 75 P amp P included This kit Contains the very best in components
35. DCV and current 29 ACV 395 resistance 3 Special 0 6V DC range tor transistor circuit measurements SPECIFICATION DCV 0 0 6 6 30 120 600 1 200V at 20K OPV ACV 0 6 30 120 600 1 200V at 10K OPV DC Current 0 0 6 6 x600mA Resistance 0 10K 100K 1M 10M ohms 58 580 5 8K 58K at mid scale Capacitance 0 002 024F AC 6V range Decibels 20 to 63dB Output 0 054 F blocking capacitor Uses two 15V U7 type batteries Black bakelite cabinet Size 53x 33x 13in Complete with test leads KIT PRICE ONLY 92 602 50 000 O P V FEATURING 57 MEASUREMENT RANGES Uses an entirely new range selection mechanism which permits the use ot a really large meter in a more compact cabinet The range selected is indicated on the meter face High speed rotary range selection knob polarity reversal switch shielded meter movement with overload protection Circuit Special pA and mA measurement ranges SPECIFICATION DCV 0 0 25 2 5 10 50 250 1 000V at 25K OP V 0 0 125 1 25 5 0 25 125 500V at SOK OPV ACV 0 3 10 50 250 1 000V at 2 5K OPV 0 1 5 5 25 125 500V at SK OPV DCA 0 254A at 125mA 0 504 A at 250mA DCmA 0 2 5 25 250mA at 125mV 0 5 50 500mA at 250mV DC Amps 0 5A at 125mV 0 10A at 250mV Resistance 0 10M ohms Output Capacitor 0 14F 400Vw in series with ACV ranges Decibels 20 to 81 5dB Operates on two 15V batts Black bakelite cabinet size 54 63x 22in Complete with test
36. Jack Porter College St WOLVERHAMPTON Lings Radio Snow Hill WORTHING G W M Radio Portland Rd G3CED GOLDRING amp GARRARD PRICES SLASHED 6 850 4 17 6d p p 2 6 SP25 Mk 11 10 15 0d p p 10 SEE BELOW FOR OTHER MODELS Goldring 800 E Eliptical Transcription Arm Cart 11 15 0d p p 4 PLINTHS AND COVERS Suitable for AT60 SP25 3000 2500 3500 Superbly finished Plinth ready Cut for use complete with Tinted Perspex Cover This unit is finished in Teak Polish and will blend in any modern home 79 6 p p 7 6 TURNTABLES Garrard 2025 TC Son 8 TAHC Diamond 9 10 0d Garrard 3000 Son 9 TAHC Diamond 9 12 8d Garrard A70 Mk 11 Less Cart 5 Garrard SL65B Less Cart Garrard AP75 Less Cart Garrard SL72B Less Cart Garrard SL75 Less Cart 19 P P FOR DECKS LEAK SANDWICH SPEAKER Enclosure 26 x 15 x12 olled matt walnut 8 ohms up to 35w handling capacity List price 45 10 each Our price 32 each p p 10 SPEAKERS AMPLIFIERS ETC Teleton CR 10T 29 9 0d p p 10 Teleton F4200 42 0 0d p p 10 Best Stereo Headphones 2 52 6 p p 5 Master Magnetic Cart Diamond Stylus 65 p p 5 LL Nova Amp 5 5 Mag and Cer Input 15 10 0d p p 10 3 Way Speaker System Teak Cabinet size eae x8 x6 10 Watts Peak each 5 19 8d GARRARD SP25 ON PLINTH Hr p p 7 6 WITH VER Nova 7500 VHF Tuner Plus 7 x 7 Amp l co Complete not wired 14 12 6d 39 0 0d p p 1
37. SOUTHEND 0702 46344 NEW UNMARKED UNTESTED PAKS 10 Dual Trans Matched O P pairs NPN Q Sil in TO 5 can sensation of the year You will be amazed at the fullness of reproduction and at the added qualities your records or tuner will reproduce Built into metal cabinet elegantly styled In simulated teak finished Ado z to blend with modern furnishings thls amplifier uses an integrated xolid state circuit with an output power of 6 watta R M S split over the two channels The amplifler is ideal for use with normal pick ups and tuners it has a double wound mains transformer and ganged volume and tone controls also switching tor Mono to Stereo tuner or pick up Other controls include treble lift and cut balance and separate mains on off switch UNREPEATABLE PRICE is 28 19 6 plus 7 6 post and insurance MAINS OPERATED CONTACTOR 220 240v 50 cycle solenoid with laminated core so very silent in operation Closes 4 circuits each rated at 10 amps Extremely well made by a German Electrical Company Overall size 2 x 2 x ir 19 6 each x 21kW FAN HEATER Three position switching to suit changea in the weather Switch up for full beater 2 kW switch down for half heat 14kW ewitch central blows cold for summer cooling adjustable thermostat acts as auto control and safety cut out Complete kit 23 15 0 Post and ins 7 6 Where postage is not stated then orders over 5 are p
38. SPECIFICATIONS Z 50 units are inter changeable with Z 30s in all applications Power Outputs 2 30 15 watts R M S into 8 ohms using 35V 20 watts R M S into 3 ohms using 30 volts Z 50 40 watts R M S into 3 ohms from 40 volts f B z 30 30 watts R M S into 8 ohms using 50 volts Frequency response 30 to 300 000 Hz 1dB UU Guaranteed With circus sana Distortion 0 0296 into 8 ohms Signal to noise ratio better than 70dB unweighted 7 gg Input sensitivity 250mV into 100 Kohms y Forspeakers from 3 to 15 ohms impedance Size 34 x23 x ins Stereo 60 pre amp control unit Designed for the Project 60 range but suitable for use with any high quality power amplifier Again silicon epitaxial planar transistors are used throughout achieving a really high signal to noise ratio and ex cellent tracking between channels Input selection is by means of push buttons and accurate equalisa tion is provided for ali the usual inputs SPECIFICATIONS Input sensitivities Radio up to 3mV Mag p u 3mV correctto R I A A curve 1dB 20to 25 000Hz m Ceramic p u up to 3mV Aux up to 3mV e Output 250mV Signal to noise ratio better than 70dB e Channel matching within 1dB eTone controls TREBLE 15 to 15dB at 89 6 Built tested and guaranteed with circuits and instructions Manual 1 09 6 Front panel brushed aluminium with black knobs and controls eSize8I1xlix4is 10kHz BASS
39. Sockets form the probes Continuity between the probes is indicated by the regular bleeping and flashing emitted by the tester As the resistance between the probes increases so the bleeps and flashes become weaker and cease altogether if the resistance is more than about 1k0 a ia Rear view of tester and cover with magnet attached Intermittent contacts are shown by random crackling noises from the speaker A shallow pot magnet bolted to the lid of the tin enables the tester to be stuck to any convenient iron or steel surface and thus leave both hands free for more important tasks BLUEPRINT SERVICE We would like to draw readers attention to the fact that the BLUEPRINT SERVICE has been discontinued and therefore no further BLUEPRINTS are available QUERY COUPON This coupon is available until 4th Dec 1970 and must accompany all queries in accordance with the rules of our Query Service PRACTICAL WIRELESS DEC 1970 PW WALLCHARTS ON AUDIO STANDARDS Standards are set to assist us Too often they confuse Somewhere in an isolated office a committee of notables sits around a table and fail to agree Given the terms of reference to define a horse they come up with the specifications for a Bactrian camel Or so it appears to the engineer and enthusiast working in and around the field of audio and high fidelity There are so many standards each valid in its own right each different Reading th
40. borrowed from the main amplifier a simple zener diode regulator circuit as shown in Fig 10a can be used to power the i c Such a supply might be the positive h t line of a 4x15 60mA Positive supply Zener diode 12 to15 v 1watt o V Zener voltage R 0 065 ohms Centre tapped Supply VzfZener voltage b n 0 025 ohms Fig 10 Zener regulator power supply circuits for a CA3048 and b MC1303P transistor amplifier or the voltage across a cathode bypass capacitor in a valve amplifier The earth connection of the i c should be at the same potential as the chassis of the main amplifier or else con siderable attention will be needed to suitable decoupling arrangements When the MC1303P is used in a preamp feeding a valve amplifier with a push pull output stage the bypassed output valve cathodes can generally provide the centre tapped supply needed for Fig 10b The value of the dropping resistor s R or r depend s on the actual supply voltage and zener diode voltage select the nearest 5 tolerance value to the resistance calculated from Fig 10 The power dissipated in the resistor is as always the product of the voltage across it and the current flowing through it answer in watts if the current is in amps 651 Circuit Boards Details for the size and assembly of the pre amplifier circuit boards and their internal screens are given in Fig 7a b and c The boards are cut to s
41. dia x b long rains 230 j 240v Price 17 6 pius 4 6 postage and insurance HAPPY FISH 7 poles 6 6 10 6 10 6 14 6 18 6 18 6 18 6 30 8 30 6 19 at f and lively indoor Planta have LUX CN 8 poles 10 6 10 6 10 6 14 6 18 6 18 6 18 6 34 6 34 6 Orimore Pontren GROWTH lighting which gives U V 9 poles 10 6 10 6 14 6 14 6 22 6 22 6 22 6 38 6 38 6 CORONET CAMERA and other rays essential to healthy 10 poles 10 6 10 6 14 6 18 6 22 6 22 6 22 6 42 6 49 8 at a fraction of maker s price flora amp fauna Special Trial Offer 11 poles 10 6 14 6 14 6 18 6 28 8 26 6 26 6 46 6 46 8 Plus this FREE ever 9 U V tube complete with choke 12 poies 10 6 14 6 26 6 26 6 50 6 50 6 ready drop front case starter tube connections and spring and shoulder strap cilps all you need incl wiring STEREO SIX British made with diagram 39 8 plus 4 6 post amp ins The amplifier precision auto focus Jens Perfect pictures in colour and B amp W 12 pictures on Kodak 127 film Extremely strong and robust 14 days free trial We guarantee to return your money in full if you cau t take perfect pictures 18 6 2 6 p amp p I2v 1j amp POWER PACK Comprises double wound mains transformer with full wave rectifier and 2 000 mid smoothing 27 6 4 6 P amp P ELECTRONICS CROYDON LTD Dept PW 266 London Rd Croydon CRO 2TH Also 102 3 Tamworth Road Croydon DEPT D 222 224 WEST ROAD WESTCLIFF ON SEA ESSEX EHPEE PAK LTO TELEPHONE
42. the values of C1 and C2 Increasing the value will 8BA bolt Battery ve Fig 2 Wiring of circuit board reduce the frequency decreasing it will increase the frequency If the frequency is increased very much however the bulb will appear to be on continuously owing to the thermal lag of the filament The small components are mounted vertically on a piece of Veroboard 9 holes long by 5 rows wide as shown in Fig 2 The centre hole of row two is Positioning of major components and circuit board CODAR rs transit mains t TRADE DESCRIPTION ACT 1968 ne Under the Trade Description Act 1968 it is illegal to give a misleading description or claim We quote a few extracts from the hundreds of letters from satisfied customers and we claim that every testimonial letter is genuine unsolicited and can be inspected at our offices e e a a_r Mr J Nicholson Elphinstone Road HASTINGS Sussex Mr A Sherwood Norfolk Road MAIDENHEAD Berks l am delighted with the CR70A at present am working on an have recently purchased from you a CODAR CRT70A May indoor aerial and getting really fine results as you rightly say at this moment congratulate you on a first class piece of equip this receiver has a high standard with a brilliant performance ment and will certainly buy from you again remain a very satisfled Mr J Walker Biscoe Drive ABINGDON Berks Wr customer received the CR70A quite safely must say am
43. to reduce self capacitance and carefully designed to avoid resonances in the amateur bands which could otherwise prove destructive especially if high power is used A Fig 5 A receiving type r f c can be used in this circuit to feed h t to the p a valve A variation of this circuit not often encountered is shown in Fig 5 in which a conventional receiving type rc can be used since it is now placed at a point of low r f potential However the anode tuning capacitor and the bandswitch are now subject to the applied h t Aerials Converting the transmitter to multiband operation is fairly simple but it is not of much use unless the existing aerial system can also be converted by an equally simple method Assuming a conventional dipole aerial is already available for the 20 metre band it is very easy to add additional dipoles for the 15 and 10 metre bands in parallel with the existing wires tying off the ends to the nearest available supports such as trees or chimney stacks or poles Fig 6 If such Additional dipoles for He M 10 and 15m Low impedance coaxial feeder Coaxial feeder Fig 6 Possibly the simplest method of converting a 20m dipole to multiband operation 666 other supports are not to be had then the extra wires may be sloped below the existing wires and secured to the same supports Fig 7 If the basic dipole is cut for 40 metres then extra dipoles for 10 and 20 metres onl
44. 0 and around the home 25 watts 240 volt Enclosures fitted AO UT Er 26 5 0 POCKET SIZE MULTI TESTER With wide angle jewelled meter movenient ceramic long life low loss switching tough impact resisting case Sensitivity 20 000 ohma volt D C 10 000 ohma volt A C 19 Ranges 0 5 25 50 260 500 2600 volts DC 0 210 50 100 600 1000 volta AC 0 501LA 2 5 mA 250 mA DC 0 6000 ohms amp megohme lOu j41 0 001 mfd l mtd 13 16 0 Carr 35 65 Gns 20 io 22uB Complete battery test P amp P 3 6 lead and instructions 4 19 6 4 channel audio mixer providing four PREMIER EXCLUSIVE MIDLAND CASSETTE TAPE Zn d RECORDER yc sane 12 115 Solid state incorporat us m ts ing piano key controls for trouble free 2 track recording Inputs for mike and aux Earphone socket Coniplete with batt eries and earpiece Size 103 x 5 x 24 1 6 1 0 0 T TAPE CASSETTES jack plu j i pr case STEREO MODEL 69 6 VERITONE RECORDING TAPE P e amp P 2 6 THE QUALITY I8 UNEQUALLED High polisbed splice free finIsh Rriooth y si rely 3 60 3 fo m ug attractively boxed C60 553 1 gl i 1200 P V C 12 6 90 31or DT6 53 1800 POLYESTER 22 6 C90 9 12 36 TT6 51 2400 POLYESTER 37 6 120 JR 3 for SP7 7 1900 P V C 12 6 C120 n I7 51 LE P Bioy POLYESTER 25 MAN TT7 7 3600 POLYESTER 50 Alf cassettes can be supplied w
45. 10 23 7 MacDonald 510 wired to din standard with p amp c 24 16 10 2018 MacDonald 310 wired to din standard with p amp c 2115 4 18 6 AR Universal Comp Arm Base amp Cov less cart 77 9 0 n 7 Dual 1219 less cart 60 8 0 54 6 Dual 1209 less cart 4212 0 38 6 Dual CK6 Base 915 0 816 Dual CH5 Cover 7 5 0 611 Dual CK20 Base for 1209 12 2 o 11 5 Dual CH20 Cover for 1210 12 2 0 1 5 Trans Ref Turnt w Arm 98 2 0 86 5 Trans Turnt w Arm amp e 57 12 0 50 19 Garrard AP 76 On application Garrard 401 3114 0 28 10 Garrard SL95B 45 9 0 38 19 Garrard SL75B 35 12 0 30 13 Garrard SL65B 19 6 O 16 12 Garrard 72B T 30 2 0 2518 Garrard 40B a 1211 0 10 16 Garrard AP75 a 2312 0 1815 Garrard SP25 Mk 2 15 9 0 11 12 Garrard SP25 Mk 3 On application P amp C for SP25 e 41 SPC4 Cover amp WB4 Base 10 2 0 9 3 SPC1 Cover amp WB1 Base 711 0 615 SPC4 Cover amp WB5 Base for SP25 playing w cov 10 0 93 Goldring GL69 Trans Unit 26 2 6 22 7 Goldring GL69 with P amp C 3912 2 33 12 Plinth for GL69 s 8 13 4 8 0 Goldring GL69 with Plinth Cover amp G800_ 52 12 3 42 10 Goldring GL75 Trans Unit 39 0 0 35 1 Goldring GL75 with P amp C 52 0 0 46 17 Goldring GL75 with Plinth Cover amp G800E 7016 3 58 19 Plinth for GL75 a i 813 4 8 0 Goldring G99 Transcription un
46. 10 NKT215 4 6 Z 6 6 For 80 1 6d For TO 5 DRECETQCUAADEAR 2N3136 5j 28502 7 BC154 8 6 BFY41 10 j NKT216 7 8 ZTX50l 5 se Finned For TO 18 1 PRESETS CARBON 2N3390 B5 28503 5 6 BC157 4j BFY43 12 6 NKT217 8 8 ZTX502 5 Finned For TO 18 1 Finned 0 1 Watt l 2N3391 4j 3N83 8 BC158 3 6 BFY50 4 6 MKT 19 6 ZTX503 5 0 2 Watt 1 3 2N3391A 6 3N128 14 BC159 4 BFY51 4j NE TRS Bie ZTX504 12 6 RESISTORS 0 3 Watt 1 6 2N3392 8 6 3N140 15 6 BCi60 12 6 BFY52 4 6 i 2N3393 3 3NI4l 14 8 BCI67 3 BFY53 3 8 NKT225 4 6 Plait E THERMISTORS 2N3394 3 3N142 1l BCI68B 2 9 BFY56A 11 8 NKT229 T Matt 591 Ad R53 STC 25 6 VAST05 17 6 i i RS i watt 5 bd K151 1k 2 6 VA3700 17 6 Post amp Packing 2 per order Europe 5 Commonwealth Air 13 MIN Len bl Mullard Thermistors also in Send 6d stamp for price list 2 watt 10 1 8 stock Please enquire Send 1 for new Comprehensive Semi 3 A MARSHALL amp SON conductor and I C list 24 pages CALLERS WELCOME 28 CRICKLEWOOD BROADWAY LONDON N W 2 HRS 9 5 30 Mon Sat Tel 01 452 0161 Telex 21492 689 Fully guaranteed Open 9 12 30 1 30 5 30 p m Thursday 9 1 p m ivi MANY OTHERS IN STOCK include Cathode Ray Tubes and Special Valves U K Orders M individually packed up to 10 1 10 to 1 2 over 21 2 per 1 over 3 post free C O D 4 extra ALL valves VALVES TRANSISTORS ZENER DIODES etc brang a
47. 12 York House 12 York Drive Grappenhall Warrington Lanes Mail Order Only C W O P amp P 1 per order Overseas 7 6 Money back if not satisfied PRINTED CIRCUITS PW 25 25 STEREO AMPLIFIER Oct 1970 Input Pre Amp LH amp RH Channels 15 pair P P 1 9 Tone Control and Drive Amp LH amp RH Channels 18 pair P P 1 All boards are drilled and tin plated and reverse side screen printed for easy com ponent and connection identification SERVITRON ELECTRONICS 18 Beckdean Avenue Poulton le Fylde Blackpool Lancs FY6 8BG Stella Nine Range Cases Manufactured in Black Grey or Blue Stelvetite and finished in Plastic coated Steel Morocco Finish with Aluminium end plates Rubber feet are attached and there is a removable back plate There is also a removable front panel in 18 s w g Alloy Now all Aluminium surfaces are coated with a strippable plastic for protection during manufacture and transit All edges are polished LIST OF PRICES AND SIZES Width Depth r Height 6 Height 74 Height S S a d s d 61 23 15 0 18 0 116 61 4i 16 3 1 1 6 1 5 0 8i 3X 180 150 150 8i 6j o S00 but Oct OECoD 104 7j 1146 226 260 I24 3j 1 5 20 I 11 9 1 17 6 12h 5j 1140 220 256 I21 8j 230 2116 215 6 ld 3j 1100 1176 220 144 9j 21i 6 370 3100 loj 6j 2 60 2156 319 164 103 300 318 0 4 60 Cases Post 4s 6d per order Discounts available on quantities
48. 12 6 CBLSl 18 EBFS0 7 6 EFl84 7 MSP4 10 PLB4 7 U403 Gj6 XHI 5 8 GAKa 8 6Fo8 14 6V6G 4 8 I2Q7GT 3oL6 9 CCHso 15 EBFSS 9 ELS2 S3 6 MUI4 7 6 PLoO0 14 0 U404 7 6 XPI 0 8 6AMS 4 6 6F32 2 9 6V6GT 6 6 128A7 8 35W4 4 6 CL33 20 EBF89 6 6 EL33 12 6 MX4O 12 0 PLo04 16 U801 23 6 Y63 7 6 6AM6 3 6 6G6 6 6X4 4 6 12867 6 3523 10 CV450 25 EBLI 14 EL34 10 6 N78 18j PLs08 29 UABCSO 6 6 OAZ 11 6AQo 6 8 6H6 3 exaG 4 8 I98H7 3 35Z4CT 8 6 CY30 12 6 EBL2l 12 EL38 92 6 N108 25 PL509 9 UAF42 10 8 OAZ200 11 6AS7G 18 6J5M 9 6X5GT 8 198J7 3 9 3525 6j CY31 8 6 EBLo1 27 6 EL4l 11 NGTI 86 PL802 10 6 UBC4l 9 8 0A7201 l0 6AT6 4 9 6556 4 7B6 11 6 198K7 4 9 37 6 6 DACS2 7 ECO0 5 EL42 11 6 0A2 6 PX4 4 UBC81 9 3 0AZ207 9 6 6AUG 5 j6J5GT 5 8 7B7 7 8 128R7 5 42 6 DAF9 4 6 ECOS 6 EL84 4 9 0C3 8 PX25 27 8 UBF80 7 OAZ210 6 6 B4G 20 6J6 3 ej7cs 89 6 14H7 9 6 5085 6 6 DAF96 7 6 ECCS2 5 9 ELO T7 OZ4 4 6 PY33 10 9 UBFS9 7 6 OAZ222 8j BBSG 2 8J7M 8 6 7C6 15 19AQo 5 50Co 8 8 DOCO0 80 ECCS3 6 3 ELL80 20 PC86 1l 6 PYSI 8 9 UCCS4 8 6 OAZ224 7 6 6BA6 5 6 7G 6 7D5 Si 20D1 10 50Cb6G SlJ DF33 8 j ECCS4 5 6 EM34 18 PC88 11 6 PYS2 5 3 UCC85 7 6 OAZ24l 4 8 6BE6 5 6J70T 7 6 7H7 6 6 20F2 14 b0L6GT DF70 9 ECCB5 5 EM80 7 6 PCO7 8 9 PYS3 7 UCFB0 8 6 OAZ242 4 8 BH6 9 6K6GT 8
49. 17 0 VOLTEX 100 watt stereo and 75P _ 443 3 8 GOODMANS ARU 180 317 8 discotheque 8 electronic GOLDRING GL com GOODMANS ARU 280 317 8 ally mixed Inputs 185 0 0 139 6 0 plete with plinth cover n GOODMANS ARU 480 5 8 5 3 and G800 cartridge 6719 0 53 19 6 GOODMANS ARU 172 D TUNERS GODDMANS MT1000 GOODMANS Trebax 100 1 9 H ARMSTRONG 523 AM FM 53 15 3 i urntabie 2 115 3 65 0 ARMSTRONG SM FM 4 T7 8 4 sooDMANS3O5 lt 3714 9 2519 6 GOODMANS Mian i 4 0 o ARMSTRONG MB decoder 910 0 s f pS cams l fie e fants e GOODMANS Attenuator 3 1 4 L zz 0 m We DULCIFMT 7S Stereo 3 00 H PHILIPS 217 S 32 09 27 4 0 rs XO 850 5000 8 8 7 0 GOODMANS Stereomax 82 10 5 PHILIPS 202 Electronic 64 0 0 84 0 0 GOODMANS Crossover LEAK Stereofetic Chassis 59 18 0 THORENS TD 125 61 19 0 Networks XO 950 6 79 4159 LEAK Stereofetic in teak case 67 3 6 THORENS 125AB 99 19 6 GOODMANS Crossover PHILIPS RH690 39 0 0 THORENS 150A Mk lI 43 12 7 32 19 6 Networks XO 5000 2 6 0 114 6 PHILIPS RH691 83 0 0 6 THORENS 150AB Mk II 4 8 7 4019 6 WHARFEDALE 8 inch PIONEER TX500 AM FM 7718 9 THORENS TX11 Cover 4 2 3 313 6 Bronze RS DD 480 313 6 PIONEER TX900 AMIFM E153 13 10 0 THORENS TD 124 11 46 15 10 39 19 6 NE QUAD Stereo FM E51 0 0 Bases plinths and covers stocked HI FI STEREO TAPE
50. 4 TRANEITOR S MJ 18 Eqvt a6 ea 1 oW T op Hat U28 Experinenters Assortinent of Integrated Circuits un amp 2 16 10W 80 10 tested Gaten Flip Flops Registers ete 8 Assorted Pi 20 ili FULLY TESTED AND ZTX300 8tud Th ea an fully Tog ais POS mur aes BOG PT REI oe Bee LANAN CODED ND120 14 each Any f testel 5 tol and uar ioj 99 1 10 100 up 1 8 each TO NPN I qty marked State voltage 5 1 000 off 1 6 each Full required 32 10 tested and coded TO 18 BRAND NEW TEXAS U33 1p Plastic case amp Silicon Rectifiers 1N4000 meree 10 f case MULLARD I C AMPLIFIERS GERM TRANSISTORS U 4 30 Bil PNP alloy trans TO 5 BCY26 2S302 4 NPN DIFFUSEDSILICON 1 Cod j 3 arn iP TO DU TAA243 Operational amplifier 70 each pas Nose gyn 535 z meu ba ae E eC PII SE TAA263 Linear AF amplifier 18 6 each 0C71 Tape Readout high TAA293 General purpose amplifier O75 switching and measure 21 each OCBID U38 0 Fast Switching Bil trans NPN 400 Mc s 2N3011 ment indicators 50V s ocst y 3 t EA 250mV OUR PRICE 10 ocs E a AT EACH 50 OR OVER 8 6 OC44 a AU PRIME AGO LIU t EACH FULL DETAILS Octo 2 OC78 Ua i P x T 1 NK FET S 2N1302 rs ON 3819 8 AFIIT Code Nos mentioned above are given as a guide to the type of 2N 382
51. 4 10 Our price 20 P amp P 3 BRAND NEW MOVING COIL DC PANEL LAMPS TEST METERS Robust superlor design dia to fit Compact and portable W 21 H 1j j hole 1 O A Length Available Red D 3 In black plastic case Avallable or Green 15 for 30 P amp P 5 as followe 3 0 3 Volts Prod on Base With Press to Test facility 3 dia to 0 15 and 0 300V Dual Range Voltmeter ft 4 hole 14 OJA Length Available 0 3 and 0 300V Dual Range Voltmeter White or Red 12 tor 80 P amp P 5 0 7 5 Amps Ammeter Our Price 1 10 0 Both types take 6mm Midget Flange each P amp P 5J Bulbs ELECTRONIC BROKERS Dept P W 49 53 PANCRAS ROAD LONDON N W 1 Tel 01 837 7781 Telex 267307 OPEN MON FRI 9 6pm drilled out to take an 8BA mounting bolt and the copper strip cut well back so that the two halves do not short circuit across the nut A two ounce tobacco tin makes a convenient case for the tester with holes for the speaker and bulb cut in the base The speaker is protected by a piece of perforated zinc across the opening and the hole for the bulb to show through is covered by a thin piece of coloured plastic sheet which is also large enough to insulate the bulb holder from the tin case To prevent the copper strips of the Veroboard from shorting to the tin they are covered by a piece of thin s r b p sheet NOTES ON USE Any convenient pair of test leads plugged into the
52. 5x7402N 10 C61 5x7451N 10 UIC83 5x7483N 10 EOD GU40UN GuxPCInpuNAND USER co NS 5 6 46 UIC03 35x7403N 10 ULC60 5 x7460N 10 UICB6 5x T480N 10 BPOl 7401N Quad 2 Input NAND Gate OPEN V1C04 5x7404N 10 UIC 0 3x7470N 10 UIC90 5 x 7490N 10 COLLECTOR 6 6 5 6 46 UICO5 5x7405N 10 UIC72 5x7472N 10 UIC92 5 7492N 10 3 UICIO 5x7410N 10 UIC 3 53x7473N 10 UIC93 8x7493N 10 BPO4 7404N HEX INVERTER 68 5 6 4 8 UTC20 5 x 7420N 10 U1C74 5 x TATAN 10 UICM 5x T404 N aa z i U1C40 5x7440N 10j WICTS 5x 7475N 10 UIC95 5 x 7495N 10 BEIM JAN ripis onan GATES ms NS ag UICNT 5 x 7441AN 10 UIC76 5x7476N 10 UICO6 5x 7496N 10 BP20 7420N Dual 4 Input NAND GATE 6 6 5 6 46 UICX1 90 x asst d 74 s 30 BP30 7430N Single 8 Input NAND GATE 66 5 6 46 Packs cannot be split but 20 assorted pieces our mix is available as PAK UICX1 BP40 7440N Dual 4 Input BUFFER GATE 66 5 8 4 6 Every PAK carries our BI PAK Satisfaction or money back GUARANTEE BP41 7441AN BCD to decimal decoder and NIT dw a i DUAL IN LINE LOW PROFILE SOCKETS Driver E pe fi BP49 7449N BCD to decimal decode TTL roi 22 8 20 17 8 14 AND 16 Lead Sockets for use with Dual in Line Intergrated UNE BP50 7450N Dual 2 Input ANDIOR NOT GATE Order No 1 24 25 99 100up expandable 5 8 56 4 8 T8014 14 pin type 7 6 6 5 3 TSO16 168 pin type A 5 10 8 6 7 9
53. 6 3A 3i 4 6 6j N4UA 4 6 2N3572 19 6 40312 9 6 BCIS2L 2 BSX19 8 6 NKT10519 6A NS T 5j 6j 66 7 10 2N696 Aj 9N3605 5 6 40314 76 BC183 2 6 BSX20 3 6 6 6 10A 108 11 68 13 15 8 17 6 19 8 25 32 2N697 4 2N3606 5 8 40320 7 6 BC184 3 BSX21 7 6 NKT20329 17A 11 6 12 6 15 6 18 19 6 24 91 6 87 8 2N698 5 2N3607 4 8 40323 6 6 BC212L 2 6 BSX26 9 J A only IA Types are plastic 2N706 9 6 2N3702 9 6 40394 9 6 BCY30 5 6 BSX27 9 6 NKT20330 2N706A 2 8 2N3703 2 6 40326 7 6 BCY31 5 6 BSX28 6 6 7 DIODES amp RECTIFIERS 2N708 8 j 2N3704 8 6 40329 6 BCY32 7 6 BSX60 16 6 NKT80111 IN461 4 6 IS132 8 BA156 4 6 BY164 11 6 0A73 1 9 2N709 12 8 2N3705 8 40344 5 6 BCY33 4 BSX61 12 6 15 IN914 1 6 I8940 1 6 BAXI3 1 6 BYX10 4 6 OA79 1 6 2N 718 5 2N3706 2 8 40347 7 6 BCY34 4 6 BSX76 4 6 NKTS0112 IN916 1 6 AAII9 2 6 BAX16 1 9 BYZIO 7 OASl 1 6 2N726 6 2N3707 8 40348 10 8 BCY38 4 6 BSX77 5 6 19 IN400 4 6 AA213 4 6 BAYIS 3 8 BYZIL 6 6 OA85 1 6 2N727 6 2N3708 2j 40360 8 8 BCY39 10 6 BSX78 5 6 NKT80113 18010 3 AAZI3 4 BAY31 1 8 DBYZi2 6 OAN0 1 6 2N914 8 6 2N3709 2 40361 9 6 BCY40 7 8 BSY24 8 2 18021 4j AAZ15 2 6 BAY38 3 9 BYZI3 5 OA91 1 6 2N916 3 6 2N3710 2 8 40362 li 6 BCY49 8 BSY25 3 NKT80211 1844 2i AAZI7 2 BY100 8 6 FST38 4 OARS 1 6 2N918 6 2N371L 2 6 40370 8 0 BCY43 3 BSY26 3 6 18113 3 BA100 3 BY103 4 6 OA5 3 6 OAz00 2 2N929 4 8 2N3715 44 6 40406 11 6 BCY 4 6 6 BSY27 3 6 NKT80212 18120 3 BAl02 4 6 BY122 7
54. 6 F amp P 8 4 SPEED RECORD PLAYER BARGAINS Mains models All brand new in maker s packing SPECIAL OFFER Famous GARRARD 3500 fitted Sono tone 9TAHCD Diamond Stereo Cartridge List price over SPECIAL PURCHASE t E M I 16 Limited Number at 10 Corr 8 6 LATEST BS R C109 4214 SPEED AUTOCHANGER With latest mono compatible cartridge 26 19 6 Carr 6 6 4 SPEED PLAYER With stereo cartridge 7 19 6 Carr 6 6 j LATEST GARRARD MODELS All types available 1025 Heavy 8fin metal turntable 2025 SP25 3000 ATGO etc S A E for latest Prices Low flutter performance 200 PLINTH UNITS cut out for Garrard Models 1025 2025 250v shaded motor 90v tap 2000 3000 3500 etc With rigid transparent plastic cover Complete with latest type Special design enables above models to be used with cover lightweight pick up arm and in position Also suitable for housing AT60 and SP25 mono cartridge with t o stylii OUR PRICE 5 15 0 complete P amp P 8 6 for LP 78 ONLY 68 P amp P idi EM E n n LATEST ACOS GP91 18C mono compatible cartridge with 6 6 BRAND NEW EMI LIGHTWEIGHT PICK UP ARM t o stylus for LP EP 78 Universal mounting bracket 80 WITH ARM REST as above Fitted mono t o stylus P amp P 1 6 and cartridge for LP 78 ONLY 20 P amp P 1 6 SONOTONE 9TAHC compatible Stereo Cartridge with M diamond stylus lied P aie 2 iD COMPATIBLE QUALITY RECORD PLAYER AMPLIFIER MK uf LAT
55. 6 OA9 2 0A202 j 2N930 5 6 2N3716 58 40407 8 BCY58 4 6 BSY28 3 6 T8121 3 6 BAllo 7 BY124 3 OAl0 2 6 2N987 10 6 2N3773 48 40408 10 6 BCY59 46 BSY90 8 6 NKTS0213 18130 2 6 BAll 1 6 BY126 3 OA47 1 6 2N1090 a 2N3819 um 40410 12 8 BCY60 ne MEE Ha 18 18131 2 6 BAl44 2 6 BY127 3 6 OATO0 1 6 2N1091 9N3893 19 6 40467A 11 6 BCY70 6 NKT80214 2N1131 5 2N3854 5 6 40468A 7 BCY71 8 6 BSY37 5j 1 RCA INTEGRATED CIRCUITS 2N1132 5 92N3854A 5 6 40600 14 6 BCY72 3 6 BSY38 4 6 NKT80215 CA3000 86 CA3020A 32 CA3036 15 CAS3050 87 2N1302 8 8 2N3855 85 6 ACIO7 6j BCZ10 5 8 BSY39 4 6 18 6 CA3005 24 CA3021 32 CA3039 17 CA3051 27 2N1303 38 8 2N3855A 6 AC126 4j BCZIl 8 6 BSY40 6 6 NKTS0216 CA3007 53 CA3022 28 CA304 22 CA3052 38 2N1304 4 6 9N3856 6 AC127 5 j BD116 22 6 BSY5i 6 6 18 6 CA3011 15 CA20903 28 CA3042 22 CA3053 10 2N1306 4 6 9N3806A 7j ACI 8 4 BD121 13 BSY52 6 6 OC 0 185 CA3012 18 CA3020 20 CA2043 28 CA3064 2R 2N1306 5 2N3858 5 AC154 4 6 BD123 16 6 BSY53 7 6 OC22 10 CA3013 2l CA3098A 18 CA3044 94 CA3000 48 2N1307 6 2N3858A 68 ACI76 5 BD194 12 BSY54 8 0C23 10j CA3014 25 CAB8028B 21 CA3045 25 CA8059 88 2N1308 6 2N3859 5 6 AC187 12 BDI31 19 6 BSY56 18 OC24 10 CA3018 17 CA3020 18 CA3046 15 CA3064 24 2N1309 8 92N3859A 6 6 ACIBS 7 8 BD132 19 6 BSY79 9 OC 5 8 6 CA3018A 22 CA2029A 33 CA
56. 60 eee Manufacturers advert page 618 or send F M Output rating S A E for Jeafleta 59 Gns High flux ceramic magnets Heavy cast chassis All carr free POP 100 POP 60 POP SO POP 30C I2in 25 WATT 14 000 gauss 14 000 gauss 14 500 gauss 8 150 lOans 150 For uses other than 8 150 Bass Guitar or 21 GNS D monthly SSA Care ep gns ments 22j and 9 mthly 5 l 9 free Pair suitable Dep thi pytmnts 2 Total 24 Total 15 1 6 MUR irposss or Dep 41 and 9 mthiy FOR BASS GUITAR OR ELECT ORGAN ETC Total 0 17 0 HI FI AMPLI FI ER Higbly sensitive Push Pull high output with Preamp Tone Con trol Stages Hum level 70dB Frequency response 3dB EOC83 807 807 QZ34 Separate Bass and Treble Controls Sensitivity 36 mililvolte Suitable for High Impedance micro Outdoor Functions etc For use with Electronic Organ Guitar String Bass etc Grain Radio or Tape Reserve L T and H T tor Radio Tuner Two inputs with associ 50 c s A C mains For 3and 15 ohm speakers Complete Kit of parte with point to 15 Gns point wiring diagram and instructiona Twin handled perforated cover 35 is Carr A RSC TRANSFORMERS L F CHOKES amp RECTIFIERS FULLY GUARANTEED Impregnated and Interleaved where necessary r 3i 6 3v 2a la 9 11 Sa or 24v 1911 AUTO Step UP step DOWN TRANSFORMERS 0 110 120v 200 230 250v 50 80 watts 19 Standard Pentode 5 000 Q or 7 000 to 812 8 9 Push Pull 8 watts EL84 to 3
57. 696 BC148 BC149 BC152 BCL75 BCY30 BCY33 ePeeseePPPSPPPPPOPSPSSZSSSSSE do LIII 0C201 O0C202 0C203 0C204 0C205 0C206 possesses sessesose Soon oo Matz iim Oe fo cou Co dO i to to 3 lo Ro i lo 5 ie SSSSRSSE 885955555065 oO O OO TAA320 MOST input bi polar stage REFERENCE LISTING MANY THOUSAND TYPES OF VALVES SEMICONDUCTORS TUBES ETC TAD100 AN active components required to construct an AM receiver De Es SL403A 3 watts Audio Amplifier In just 2 minutes find out how you can qualify for promotion or a better job in Engineering n That s how long it will take you to fill in the coupon below Mail it to B LE T and we ll send you full details and a free book B L E T has successfully trained thousands of men at home equipped them for higher pay and better more interesting jobs We can do as much for YOU A low cost B LE T Home Study Course gets results fast makes learning easier and something you look forward to There are no books to buy and you can pay as you learn on SATISFACTION OR REFUND OF FEE terms If you d like to know how just a few hours a week of your spare time doing something constructive and enjoyable could put you out in front post the coupon today No obligation THEY DID IT SO COULD YOU My income has almost trebled my life is fuller and happier Case History G 321 In addition to having my salary doubled my future is assured
58. 7 HN309 20 PCL84 8 6 T4l 17 6 UY41 8 8 3Q5 7j 6D6 3 8 698A7M 7 I2AT7 6 30FLI 15 5763 12 DY86 8 EFS9 S KT36 18 PCLS5 9 8 TDD4 S 6jUYSD 6 6 384 6 3 6ES 7 6 6807 7 12AU6 5 9 30FL12 18 7193 2 i iDYs7 66 EF4l 10 KT6l 22 6 PCL86 9 8 TH4l 88 VMP4G 17 3V4 6 9 6F1 12 6 68G7 6 12AU7 5 8 30FLI4 15 6 7475 14 K88CC 12 EF50 5 KT66 30 PD500 28 U10 J6 VP4B 25 BRAGY 10 6 6F5G 8 68H7 83 8 12AX7 6 3 30L15 17 A61 9 6 EA50 3 6 EFBO0 4 6 KTSl 85j PENA4 20 Ul4 7 8 VR105 30 6 6 BU4G 5 6 6F G 5 168J7 8 12BAG 6 30L17 17 ATP4 8 8 EABCSO 6 6 EF85 7 KT81 7105 PENBA 20 U19 BB VR160 30 8j BV4G 8 6F8G 5 6 6SK7GT 4 9 I2BEG 6 3 30P4 29 6 ATPo 12 j EAF42 10 EF86 6 6 3 60 PEN45 7 U20 15 6 VT25 18j SY3GT 8 6Fll 6 6 68L7GT 12C8GT 5 30P12 16 ATP 8 6 ED4l 10 EF89 5 6 KT88 34 PEN46 4 U26 18 6 VTS 80 5Z4G 7 6Fl3 8 6 68N7GT 5 6 12El 20 30P19 15 AU2 80 EB91 3 EF91 8 6 KTW6l 12 6 PL36 10 8 UT8 46 VUlll 8 8 6 30L2 15 6Fl4 18 6 68Q7 7 6 12J9GT 2 6 30PLI 16 AUS 8 8 EBC33 8 8 EF92 2 6 KTZ41 PL81 89 8 UI9 18 8 VUI20 12 6 6A7 15 6F23 16 GU4GT 12 12J7GT 6 6 30PL13 18 6jAZI 8 EBCAl 9 9 EF98 15 ML4 17 6 PL82 8 8 U951 10 8 VU508 35 6A8G 18 6 6F24 14 6U G 7 8 12K7GT 7 30PL14 15 AZ31 10 EBC90 4 9 EFI83 6 6 MLO 7 6 PLO3 7 6 U301 12 6 WSIM 13 6 GACT A 6F25 15 6V6M 18 2K8GT 8 35A5
59. 8 16 4080 200 400 V Resistance 8 Ranges 0 00 100 000 ohms 10 megs Centre scales at 12 1 00 and 120KQ D C Current 10 Ranges 0 50 160 400 80014 8 16 200 400mA 8 164 Decibels 12 Ranges 12 to 74 D C Sensitivity 20 000 ohms per voit or 10 000 ohms per volt function of scale EA switch Frequency Response 20Hz to beyond 200kHz Accuracy D C 3 A C 5 Test Leads one red one black each 45in long Multiplier Resistors AU 1 carbon b er 8 film Recommended Liat Price 216 19 0 94 GNS Assembled Price 12 GNS Standard Long Double Triple Bin 150ft 2 8 Zin 225ft 2 9 Sin 300ft 4 din 900ft 13 din 300ft 4 6 din 450ft 5 8 din 6001t 8 Sin 1 800ft 25 bin 600ft 7 8 bin 9001t 10 8 Gin 1 200ft 15 5iin 9 400tt 94 Sin 900f amp 10 6 5 in 1 200ft 13 bin 1 8001t 19 7in 3 600tt 44 Jin 1 2001t 12 8 Zin 1 800tt 18 6 in 2 400ft 27 Quadruple Sin 6001t 8 6 Postage 1 reel Post free less 5 on three reels Quality and Trade enquiries invited NOTE Large tape stocks at all branches Stockists of Leak Quad Chapman Goodman Armstrong Tripletone Linear Rodgers Truvox Ferrograph Wharfedale etc etc ECHNICAL TRADING All Mail Orders ye ARUNDEL 33 x BRIGHTON 3 255 Peas te LONDON Vi osse seis Fon te PORTSMOUTH 1225359 Road sk SOUTHAMPTON 72 Fas Sereet PERSONAL CALLERS Welcomed at all Branches
60. 85 6 BC116 BCl25 BC1 6 BCHZ7 BC148 BO149 BCl67 BC172 BCi77 BC186 BCI89L BC184L BC212L BCY30 BCY31 BOY32 BCY33 BCY34 BCY38 BOY42 BCY43 BCY71 BOY72 BOZli 7 8 BDI 1 18 BD123 16 6 BD124 12 BFl16 5 BFEil7 9 6 BF167 5 BF173 6 6 BE180 7j BF181 6 6 BF182 8 6 BF184 8 6 BFI85 8 8 BF194 4 6 BFi195 5 6 BF200 10 6 BF224 6j BF225 6 BF244 9 6 BFX12 4 6 BFX13 4 6 BFX99 7 BFX30 9 BFX44 7 6 BFX85 7 BFX86 6 BFX87 6 BFX88 5 BFY18 6 6 BFY20 12 8 BFY50 4 6 BFYS1 4 6 BFY52 4 6 BFY90 18 6 BSX19 3 6 BSX20 8 6 BSX21 7 8 BSX76 4 6 BSY26 3 6 BSY27 3 6 BSY28 8 6 BSY38 4 6 BSY39 4 6 BSY51 6 6 B8Y56 18 BSY95A 2 6 BY100 BY124 BY126 BY127 BYZi0 BYZI1 BYZ12 BYZI3 5 MJ480 19 6 MJ481 95 MPF102 8 6 MPF103 7 6 MPF104 7 6 MPF105 7 6 NKT213 6 NKT214 4 6 NKT216 7 6 NKT217 8 6 NKT224 5j NKT241 5 6 NKTQ61 4 NKT271 4 NKT272 4 NKT274 4 NKT275 4 NKT278 3 6 NET281 5 6 NKT403 15 NKT404 NKT405 15 NKT773 5 NKT10439 OA5 OA10 OA4T OA70 0479 OA8L OA85 OA90 1 6 OA91 OA96 0A200 04202 04210 OC1I9 0C20 0C22 0C23 0C24 OC25 0C26 0C28 0029 OC35 Oc3 THYRISTORS 50 5 6 See previous page 100 5 6 7 6 11 11 200 7 6 8 18 18 300 350 M By 8 9 50 VALVES 042 6 6 30C15 15 EY51 8 OB2 6 6 30C17 16 EY86 8 OZ4 6 30018 15 EY87 8 6 IL4 2 6 30F5 17j EZ
61. ADI61 AD162 matched 14 pr Values available BFY51 BSX20 BY 164 BY238 C106B1 MC140 MJ480 MJ481 MJ491 MPF102 NKT403 NKT405 0A47 OAS OA91 OA95 0499 0A200 0A202 0c71 TIP3IA TIPS2A TIS43 ZTX300 ZTX301 ZTX302 ZTX303 ZTX304 ZTX600 ZTX501 ZTX502 ZTX503 ZTX504 ZTX530 ZTX531 BC147 BC148 BC149 BC153 BCl54 BCIS7 BC158 BC159 BCi67 BC 68 BC169 BC177 BC178 BC179 BCIS2L BC183L BC184L BC186 BC212L BC213L BC214L BCY70 BD121 BD1 3 BD1 4 BF167 BF178 BF180 BF194 BF195 BFX29 BFX84 BFX85 BFX87 BFX88 BFY50 45 6 9 8 14 6 4j 4j 4i 6 4 6 4i 5 14 8 12 3r j U 7 11 10 to 99 see Bol below 1to9 100 up E12 18 E 2 5 2 Ki 25 E24 3 2 E12 6 E24 8 E12 1 6 all quantities E12 1 6 all quantities E12 1 9 ali quantities Prices are in pence each for same ohmic value and power rating NOT mixed values Ignore fractions of 1d on total res stor order MULLARD polyester C280 series 950V 20 0 01 0 022 0 033 0 047 8d ea 0 068 0 1 9d ea 0 15 11d 0 22 1 10 0 33 1 5 0 47 1 8 0 68 9 8 1u 9 9 1 5uF 4 2 9 2 4 9 MULLARD SUB MIN ELECTROLY TIC C420 range axial lead 1 8 each Values 4F V 0 64 64 1 40 1 6 25 25 16 25 64 4 10 4 40 5 64 6 4 6 4 25 8 4 8 40 10 10 16 10 64 12 5 25 16 40 20 16 20 64 25 6 4 25 32 4 32 10 32 40 32 64 40 16 40 2 0 6 4 50 25 60 40 64 4 64 10 80 2 5 80 16 80 95 100 64 125 4
62. BP53 7453N Expandable 4 wide 2 tipat and or mad CEU cur LN MU c Me cM feas ca nor gate 3 68 5 6 4 0 RTL FAIRCHILD U S A l C s J t s ji 5j8 4 BP60 7460N Dual 4 Inpu PERA sig j 6 RTL Micrologic Cireuits Qiy cea Sach BP70 7470N Single JK Flip flop edge triggeren 9i 8 Ti Epoxy case To 5 temp range 15 C to 55 C 1 11 1221 e Ed gt hs p n T pL 900 Butler e e z Bi m BP72 7472N Single Master Slave JK Flip top 9 8 2 AL 914 Dual tos input GATE kd Es T g F 6 8 5 6 BP73 7473N Dual Master Slave JK Flip lop 10 9j 8 8 AL 938 J K ma Hop BW M eee TRS 10 96 9 ull data and circuits for in o0 el orin price eac BP74 7474N Dual D Flipfop 10i 9i 8 6 LA703E Linear RF IF AMPLIFIER M 10 89 83 BP75 7475N Quad Bistable Latch Me 0 Me 10 9 6 PLASTIC CABE To 5 6 Icad up to 100 mics BP76 7476N Dual Master Slave eligen with P preset and clear E m 10 9 6 DTL DIGITAL I C s a H PTL dual in line package Price BIB WANN CEOUUDIDHBIANTAQUS Ter BS ge 80 Type MC844P expandable dual 4 input NAND Power Gate 10 each BP90 7490N BCD Decade Counter dis E 22 6 20 17 6 Type MC845P Clocked Ene flop r A e s each I n a Type 862 Triple 3 input N SAND NOR Gate D 23 ao j eac 2 d s BP92 7492N Divide by 12 4 Bit binary counter 22 6 20 17 6 FULL DATA SUPPLIED WITH UNITS BP93 7493N Divide by 16 4 Bit blnarycounter 99 6 20 178 T BP94 7494N Dual Entry 4 Bit Shift Register 22 6 90i 17
63. Drilled chassis bandspread tuning step by step instructions and of course first class reception and value for money Illustrated Catalogue of Selected Kits and Com ponents 2 6 P amp P Free Cheques Postal Orders to Dept P W Galleon Trading Co 25 Avelon Road Romford Essex E M J LOUDSPEAKERS 13in x 8in Bass 2 Tweeters amp Crossover 75 Longthrow Bass 6lin 47 6 5in 37 6 Tweeters 3iin 16 6 Crossovers 16 Available in 3 8 15 ohms Teak Cabinets to exact E M I spec Metrosound ST20 Amplifiers 27 10 All P amp P Free S A E full list SONTEL 183 Clapham Manor St London S W 4 Tel 01 720 3559 BC108B 2 3 BC109C 2 6 2N3705 SOV 800mA 100MHz 2 9 Postage 1 SAE list GREENWELD 24 Goodhart Way W Wickham Kent AERIAL BOOSTERS We make four types of r f high gain transistorized pre amplifiers Wideband Radio Type L10 39 This covers the Medium and Short Wave V H F F M Radio Type L11 59 This covers the V H F radio band V H F Television Type L12 59 Please state Band and I and III U H F Television Type L45 59 Tunable over the U H F band S A E for Details P and P 1 VALVE BARGAINS Any 5 9 10 14 100 5 10s ECC82 BCL80 EF80 EF85 EF183 EBF89 EB91 EY86 PCC84 PCC89 PC97 PCF80 PCF86 PCL82 PCL83 PCL84 PCL85 PL36 PY33 PY81 PY82 PY801 PY800 30L15 7 day Money Back Guarantee VELCO ELECTRONICS 62 Bridle St Ram
64. Fig 10 The G5RV multiband dipole At a height of about 32 feet the the best match between aerial and feeder will be obtained on the 20m band If accurate matching is required on the other bands an aerial tuning unit may be interposed at the junction of the co axial and open wire feeders Conclusions These simple modifications to transmitter and aerial will permit operation on the 10 15 and 20 metres bands which will greatly increase interest in DX working and often enable contacts to be made with those countries that have proved so elusive on 20 metres a CORRESPONDENTS WANTED P F anyone of my own age 18 interested in Amateur Radio and Aeronautics P Jones 28 St Fagans Cardiff CF5 4SP pentriend of my own age 12 who is Interested in short wave listening Stephen Champion 16 The Orchard Kings Langley Herts WD4 8JR anyone who knows how to wire up a crossover network In an audio system The unit am particularly interested In is a Harrow 3 way crossover network model HN 3 T M Blea Tilings Fair Mile Henley on Thames Oxon anyone of my own age 18 who is Interested n short wave listening l Simpson 2 Taylor Cottages Derryhale Portadown Co Armagh N Ireland Someone who speaks English Is about 17 years old and who likes anything connected with electronics B Cameron 84 Pownall Street Masterton New Zealand TAPESPONDENTS WANTED i boy or girl of my own age 17 h
65. GUARANTEE f within 3 months of purchasing Project 60 modules directly from us you are dissatisfied with them we will refund your money at once Each module is guaranteed to Please send work perfectly and should any defect arise in normal use we will service it at once and without any cost to you whatsoever l provided that it is returned to us within 2 years of the purchase date There will be a small charge for service thereafter No charge for postage by surface mail Air mail charged at cost m a for which I enclose cash cheque money orver Stereo FM tuner first in the world to use the phase lock loop principle Before production of this tuner the phase lock loop principle was used for receiving signals from space craft because of its vastly improved signal to noise ratio over other systems Now for the first time the principle has been applied to an FM tuner with fantastically good results By the in clusion of other original features such as varicap diode tuning printed circuit coils and an L C in the specially designed stereo decoder the tuner has an unsurpassed specification which also in corporates a squelch circuit for silent tuntng between stations A F C and A G C Sensitivity i such that good reception becomes possible in difficult areas foreign stations can be tuned in suitable conditions and often a few inches of wire are enough for an aerial In terms of high fidelity this tuner has a lower l
66. Goodmans Loudspeakers Limited Axio Works Lancelot Road Wembley Middx Tel 01 902 1200 um Please send me L Fuil colour manual i Construction manual E Tick as required i Name beei ul SEMICONDUCTORS amp COMPONENTS SOLE AGENTS FOR SOLID STATES DEVICES INC USA IN U K BRAND NEW GUARANTEED PANEL METERS TRANSISTORS 38 Series FACE SIZE 42 x 42mm All prices for 1 9 pieces 26301 Aj 2N3402 4 6 3N143 13 8 BCI608C 3 BFY75 6 NKT237 7 Soya 37 8 104A 85 200A 32 6 500A 27 6 50 0 50uA 85 28302 4j 2N3403 4 6 3NI152 17 6 BC169 3 6 BFY76 S NKT238 5 100 0 100 A 82 6 500 0 500uA 25 IMA 25 BMA 26 10MA 2G303 4j 2N3404 6 6 BC169B 2 9 BFY77 11 6 NKT240 5 6 25 50MA 25 100M A 25 500MA 25 IA 25 5A 25 10V 25 24806 8 6 2N3405 9 R C A BC1690 3 BFY85 9 NKT241 5 6 20V 25 50V 25 300V 25 500V 95 26308 6 2N3414 4 6 40050 10 8 BCI70 2 6 BFY90 13 6 NKT 281 5 6 26309 8j 2N3415 4 8 40251 17 6 BC171 3 BPX25 37 NKT 713 4 SILICON RECTIFIERS 26371 8 2N3416 7 6 40309 6 8 BC172 8 BPX29 36 NKT 781 6 PIV 50 100 200 400 600 800 1000 1200 28374 4j 2N3417 7 6 40310 9 j BC175 4 6 BPYl0 29 NKT104196 IA 2 9 6 3 S88 36 39 4 2Gs81 4 6 2N3570 25 40311 7j BC182 9 6 BRY39 9 6 NKT10439 7
67. Horn Tweeters 2 18 Ke s 15W ohm 59 6 ELAC MOVING COIL Deluxe cone tweeter 3 or 15 ohm 85 TWO WAY 3000cps CROSSOVERS 3 or 8 or 15 ohm 19 SPECIAL OFFER 80 ohm 21in 21in dia 36 ohm 3in 25 ohm Sin dia 6 x 4in 8 x Bin 7 6 EACH 15 ohm 3jin dia 7 x 4in 8 x bin TYPE 8 ohm 6 x 4in 3 ohm 2 in Sin Sin 5 x Sin 7 x Ain LOUDSPEAKERS P M 3 OHMS 6jin 22 8 8 x bin 25 8 x Qhin 18 Sin 35 10 x Bin 38 Sin WOOFER 8 watts max 20 10 000 cps 8 or 15 ohm 86 ELAG 8 in De Luxe Ceramic 8 ohm or 15 ohm 50 RICHARD ALLAN LOUDSPEAKERS twin cone 8in or 10in or 12in 8 or 15 ohm 39 6 OUTPUT TRANS EL84 etc 5 MIKE TRANS 50 1 5 SPEAKER COVERING MATERIALS Samples Large S A E GOODMAN S OUTPUT TRANSFORMER 4 watt push pull for 8 8 and 15 ohms 17 0 VHF FM TUNER FRONT END 88 108 Mc s Transistor FM tuner oscillator and fres quency changer printed circuit Slow motion tuning gang condenser Ready wired and tested including two transistors AF124 snd AF125 A total of 29 components Size 24 x2x2in Requires I F and Detector stages 10 7 Mc s 9 Volt Connection de POST FREE tails supplied but we have no further information available 45 ALL EAGLE PRODUCTS SUPPLIED AT LOWEST PRICES ILLUSTRATED EAGLE CATALOGUE 5 Post Free BARGAIN AM TUNER Medium Wave 4 Transistor Superhet Ferrite aerial 9 voit BARGAIN 4 CHANNEL TRANSISTOR MIXER 3 Add
68. Input pre amplifier Common earth on tone control and drive amplifier boards Input RH C9 RH power module pre amp board c Treble Bass d Volume Balance control control control R18S control C10 R19 b 7 RH Tone control 7 n and drive amp a p amp 10k log D gt ae channel 7Z d Ps Com E Controls C 10 R19 ganged p LH Tone control Z and drive amp Ev 4 R18 input LH Pwer 10k anti log channel module VR4 B Stereo 4 10k ig ee Jhb om p o Mono A 7 Mono filter eres Zp Com E C23 LH channel LH eee board Sia RH C23 a C19 Id C19 C21 RH channel Denotes 29 R28 R29 R28 screened LH RH leads A Fig 9 Rear view of the wiring to the various panel c8 R14 controls See text for com ments on the use of screened leads Input pre amplifier C6 R17 RH Channel ch R17 LH Channel C7 R14 ca Input pre amplifier C2 LH Channel Input pre amplifier C2 RH Channel ces S1 A LH Channel P Input pre amplifier common earth line C23 RH Channel RH lt q Fig 10 Wiring of the input selector switch wafers and the associated input sockets For clarity the wiring to the L H channel input sockets is omit ted but is similar to the R H LH channel Tape Tape Tape Ceramic Magnetic Radio record replay head PU PU outlet Pu2 Pu Note LH input sockets resistors and 1 B wiring same as for RH channel as shown 655 signal generator and an audio milli volt
69. July 61 to May 70 102 volumes Offers 37 Priolo Road Charlton London S E 7 MULLARD BRIMAR Ei80F valves gold plated pi s guaranteed 5 6d post paid Jack Porter Limited Electronics College Street Worcester INTEGRATED CIRCUIT AUDIO AMPLIFIER KIT 3 Watts R M S per Power output channel Sensitivity 160 mv input for 3 watts output Output load 7 5 to 15 Frequency response 15 Hz to 50 kHz 3db down Treble cut and boost 18 db to 12 db Bass cut and boost 14 db to 12 db Noise level 80 db max referred to 3 watts output Hum 70 db max referred to 3 watts output Crosstalk 40 db Distortion at 3 watts output 1 max Total harmonic Price of kit of parts and full construc tional details 15 TELEVISION CITY Dept PW1 50 Richmond Road Kingston upon Thames Surrey Tel 01 546 3961 100 yards from Station Daily 9 30 5 30 Friday 9 307 Closed Monday ELECTRICAL BEST EVER 200 240 VOLS MAINS SUPPLY FROM 12 VOLT CAR BATTERY Exclusive World Scoop Pufchase The fabu lous Mk 12D American Heavy Duty Dyna motor Unit with a Massive 220 watt out put and giving the most brilliant 200 240 volt performance of all time Marvellous for Television Drills Power Tools Mains Lighting AC Fluorescent Lighting and all 200 240 volt Universal AC DC mains equip ment Made at tremendous cost for U S A Govt by Delco Rem
70. MT 65 Chassis A l 3 75 0 ARRARD Al 3 speed ingle Player g 5 Sce AUDIO DEVELOPMENT AD 96K Magnetic Cartridge s PA CKAGE 2 WHARFEDALE DENTON Speaker Systems ex in fre Compact Teak Cabinet at shown U K carriage 40 TOTAL RECOMMENDED LIST PRICE 148 5 1 1 32 0 0 All units available separately MADE ESPECIALLY FOR LASKY S BY FAMOUS MAKER MAINS OPERATION 12 HOUR ALARM AUTO SLEEP SWITCH HOURS MINUTES AND SECONDS READ OFF SHOCK AND FORWARD AND VIBRATION BACKWARD TIME PROOF ADJUSTMENT BUILT IN SILENT OPERATION SPEO QUANTITIES BUZZER MOTOR ous J 2 UAN TITS U Project 60 Is a range of modules which connect together to form a complete stereo This unique DIGITAL CLOCK is now available EXCLUSIVELY FROM amplifier Tha modulea are Hin hl j jain power amp 2 Stereo 0 pre amp au T MO M eS PZ4 stabilen power euppil dA cumpla te AM setinde ara sq touc no cer Ne IA including e o a d z one tereo stiens e a ON OFF AUTO and AUTO ALARM sleep switch 10 minute division click STEREO 60 SPECIFICATION set alarm up to 12 hour delay time adjustment Ultra simple mechanism and Input sensitivities Radio up to 3mV Magnetic Pick up 3mV correct to R 1 A A curve high quality manufacture guarantee reliable operation and long life z dB 20 to 25 000Hz Ceramic Pick up up to 3mV The sleep switch will automatically turn off any appliance radio TV light etc Auxillary up to 3mV Output 1 voit Signal to no
71. Mongolian yarsh Swahili Hii ni Afrikaans Dit is Hindi Urdu Yeh hai I hope that the above will be of use to some of you All reports which should be in frequency order must reach me by the 17th of the month at the following address 5 Ranelagh Gardens Cranbrook Ilford Essex 631 7 wiles ww 382 P 4 z A month The Lf bands true to form have begun to improve and it can only be hoped that this will continue thus enabling Santa to fill waiting ears with Christmas DX Talking l f Paul Leach Cheshire informs that a listen on 1880kHz in the evenings will often be re warded by sigs from HBOXKZ QSL via G3TXF Paul hopes to take the R A E in December before going to school in GD land Twenty metres have proved its worth for those who were prepared to go on owl watch Late nights and early mornings appear the most fruitful times to QRX Surprise of the month was undoubtedly ten metres True its a temperamental old band with a character all of its own but there were some very good open ings especially towards the end of the month North America and Japan were heard on two occasions P Fereyear Essex Marconi No 9 set built in 1943 no mention of any antenna boy they really knew how to build sets in 1943 He says that PAOPN can usuall be logged at 1100 around 1805k Hz On 3500kHz Paul logged CR7GJ F6ACM FC OY7ID PYIHA VOIFG VS6DO WAIIKG 9V PP The majority of log
72. Q or 10 N 14 9 200mA 6 3v 4a e t By Pusb Pull 10 watts 6V6 ECL86 to 3 5 8or 200mA 6 3v 4a 6 3v 3a ov 15 Q sre Push Pull EL8 to 3 or 16 Q 10 12 w Pusb Pull Ultra Linear for Mullard 510 etc Pusb Pull 15 18 watts sectlonaily wound 6L6 KT66 etc for 3 or 15 Q 35 9 Push Pull 20 watt higb quality Ena wound EL34 6L6 KT66 etc to 3 or 15 59 9 SMOOTHING CHOKES 150mA 7 10H 250 Q 12 9 100mA 10H 200 Q 10 9 80mA 10H 350 2 8 9 GOMA 10H 400 Q 4 1 SELENIUM RECTIFIERS F W Bridged All 6 12v D C output Max A C Input 18v 1a 4 8 2a 6 11 3a 9 1 250 0 250v 70mA 6 3v 9 250 0 250v 100mA 6 3v 3 5a sew 250 0 250v 100m4A 6 3v 2a 6 3v la 300 0 350v 80mA 8 3v 2a 0 5 6 3v 2a 300 0 300v 180mA 6 3v 4a 0 5 Suitable for Mullard 510 Amplifier 350 0 350v 100mA 6 3v 4a 0 3 150m 4 607 MAIL ORDER DET ae SHELF UNIT MAYES RD C Two teak finish shelves on a black frame RADIO LID LONDON overall size 28in x 25in x 19m Ideal for hi fl equipment amplifiers speaker cabinete m etc The perfect answer for housing unit audio N t40 MAYES RD N 22 888 320 Ii Sa i TRANSFORMER SCOOP d PLEASE NOTE P amp P IS FREE Primary 110 220 250 v fused 2 x 3 15 volt 1 amp Secondary Secondary 220 v at 50mA 6 3v 250 volt Primary Can be used WESTON MILLIAMMETER at 1 amp Overall size 23 x 2 x as 6 3v heater transformers Modern clear plasti
73. Radio Technicians Previous experience is not necessary but a genuine interest NORTH EAST LONDON in radio work and a willingness to be taught are essential POLYTECHNIC As Day Release facilities will be offered in appropriate AUDIO TECHNICIAN instances a good general education particularly mathematics Grade T9 is desirable APPOINTMENTS ired ce Lang Labora tory complex Must have several years Applications should be made in writing in the first instance cal experience in sound radio to MISS I S THOM A M LP M OK HNC e COLI Ail rato INDUSTRIAL RELATIONS PERSONNEL MANAGER M cg RADIOMOBILE LIMITED M ERE GOODWOOD WORKS pps D RUM MEL NORTH CIRCULAR ROAD LONDON N W 2 Apply by letter in first instance to meee SSeS EE Ea mamas mm the Staffing Officer North East London 693 r Folytechnic Romford Road Stratford 15 SITUATIONS VACANT continued SERVICE SHEETS continued EDUCATIONAL continued Radio Operators There will be a number of vacancies in the Composite Signals Organisation for experienced Radio Operators in 1971 and subsequent years Specialist training courses lasting approximately 8 months are held at intervals Applications are now invited for the course starting in September 1971 Salary Scales During training with free accommodation provided Nat the Training School Age 21 848 per annum 22 906 Es 23 943 n 24 981 A 25 and over 1 023 i On succ
74. TERMS Deposit d 9 monthly payments of 2 Total 2 Primaries 200 250v 50c s Bcreened FILAMENT or TRANSISTOR POWER PACK morr CLAMPED TYPE 23 x2i x 2 In 1 6a 8 9 6 3v 2a 9 9 6 3v 3a 18 9 FORMERS i 2 a 19 11 3a 21 11 5a 25 11 20 9 Ba 300 0 300v 130inA 8 3v 4a c t 6 3v 150 watts 33 6 250 watts 49 9 500 watts 105 35 OUTPUT TRANSFORMERS FOR GUITAR VOCAL OR INSTRUMENTAL GROUP A 2 or 4 input 2 vol controi Hi Fi unit with Separate Bass and For 200 250v A C mains For 3 or 16 ohm speakers Send S A E for leaflet Terms Deposit 3 14 0 and 9 monthly payments of 42 19 Gns IN TEAK OR AFRORMOSIA VENEERED CABINETS L125 50 WATT 10 000 lines 3 or 15 vynair finish Fittet ohms State impedance 10 000 lines pair of 12 50 watt 15 ohms Carr 8 9 conservative rating 5 Gns Impedance 8 15 ohme Carr 7 6 R S C BASS REGENT 50 WATT AMPLIFIER A powerful high quality all purpose unit for lead rhythm bass guitar Loudspeaker unit horizontal or vertical mounting Two extra heavy duty 12in Loudspeakers Carr 30 taneous use of up to four pick ups or mikes Bass and Treble controls Send S A E for leaflet FAL PHASE 50 AMPLIFIER 50 Watt FAL PHASE 100 AMPLIFIER Solid state 3 Separ 100 Watt Solid State Ind Bass and Treble inputs Piua master Controls Output for EEE volume Control Ind Bize 17 x 7 x 7j 200 250 A C mains speaket s 3 30 obms Peak Output rating Protective circuit to
75. The transmissions are on Greater Eso i S T B Uckfield Burgess Hill a M Hassocks anst os DG 95 3MHz in the v h f band with horizontal polarization The Radio London transmitter is sited at the BBC s Wrotham Kent transmitting station It uses a directional transmitting aerial to serve almost the whole of Greater London and an area extending southward to include Sevenoaks Tonbridge Tunbridge Wells East Grinstead Crawley and parts of Reigate westward to Staines and parts of Slough and Maidenhead and northward to Potters Bar Loughton and Epping For listeners equipped with outside aerials the service area also includes Heathfield Burgess Hill Haslemere Woking High Wycombe Watford Hemel Hempstead St Albans Hertford Harlow and Brentwood and extends into Reading Chelms ford and Basildon Bedford amp District A R C The above club meets every Thursday evening in our own clubroom at The Dolphin Inn The Broadway Bedford Visitors are always welcome and details of some recent meetings are de tailed below The Manufacture of Printed Circuit Boards at Home Come and see the etchings G3XDU 624 The famous G6CJ Aerial Circus at the Civic Theatre Bedford G6CJ Lee s Morse Night or Charlie Whiskey Fun G3XNG Members equipment Five minute talk and demonstration Junk sale Auctioneer Extraordinary G3XKB Tape Recording includ ing Receiving and Transmitting Te
76. Tun 32 0 Decca T2000 T n 59 0 Decca X70 Decoder e 7 7 Dulci 207 Amp Chassis 25 0 Dulci 207M Amp Case 30 0 Duici FMT7 Tun 23 0 OOooooooooooooooooooooooo o o oN 156 12 10 7 350 14 17 5 39 5 42 0 48 10 41 19 31 14 81 19 93 19 00 cooo o oo oo ooo oooo ooo oooooooo ooooooncoo0 o gt o o oooooo o6060000000000000000000000 o o oo O HI FI Dulci FMT7S Tun i Ferrograph F307 Amp Case Leak 30 Amp Chassis Leak 30 Amp Case T Leak 70 Amp Chassis Leak 70 Amp Case Leak Stereofetic Tun Chas Leak Stereofetic Tun Case Lux SQ1220 Amp aie Lux SQ505 Amp x Lux SQ77T Amp Lux SQ606 Amp es Lux HQ555 Tun Amp Lux WL515 Tun b Lux WL313 Tun Metrosound SM Amp Sinclair N vts 2 30 Amp e 2 10 Amp Stereo 60 Control Unit Stereo 60 Filter Unit PZ 5 Supply Unit 3s PZ 6 Supply Unit PZ 8 Supply Unit IC 10 Amp r Z 12 Amp PZ4 Power Supply bu Stereo 25 for 2xz12 Amp 2000 Amplifier E 2000 FM Tuner 3000 Amp Neoteric 60 Project 60 FM Tuner Stereo Decoder 4 Sugden A21 Amp of Teleton SAQ 203E Amp Teleton A150 Amp Teleton CR10T Tun JAmp Teleton TFS50 Tun Amp Teleton GA101 Amp Ao Teleton GT101 Tun Teleton CR10T amp Speakers Teleton CR24 Tun Amp Teleton R4200 Tun Amp Teleton CR55 Tun Amp Teleton STQ204 Tun Amp Teleton F2000 Tun Amp Teleton SAQ5015 Amp Wharfedale d Tu
77. United Nations Radio Service at 2100 Chris Vernon of South Ruislip made his own super het receiver and used it with a 20ft long wire to hear 6620 Radio Peking in English ffom 2155 to 2215 9625 CBC Radio Canada in English from 0715 to 0745 Aen ABC Australia in English from 0840 to 11950 Radio Japan in English from 2030 to 2100 15255 Radio Vilnius Lithuania in English at 2235 2300 Simon Hamer of New Radnor in Wales has two receivers 2 Mullard domestic receiver and a 10 transistor portable and two aerials 25 and 60 foot long wires This line up enabled him to hear 11710 ABC Australia from 0645 to 0915 in English n ABC Australia in Vietnamese Eng ID at 21 p BBC Atlantic relay Ascension Island at 3 21690 Windward Islands to U K s off at 2200 THE BROADCAST BANDS Malcolm Connah Frequencies in kHz e Times in GMT Colin Blanchard of Sutton Coldfield has a 5 valve Mullard domestic superhet and a 50 foot long wire and he has heard the following stations 9625 Radio Israel with news in English at 2100 9912 All India Radio with music Id in Eng at 2050 11720 VOA Tangier with Jazz Hour from 2345 to 2400 11725 Radio Peking in English from 2100 to 2130 15320 ABC Australia Id at 2255 news in Eng at 2300 Nicholas Brooks of Naseby used his Astrad Auriga receiver and 120 foot long wire to hear several stations including 11620 Ail India Radio Delhi in English at 1930 11660 Radio Pakistan Karachi in E
78. VCR517B56 6 30L2 14 30PLI3 18 VCR517C45 674 5 I30PLI4 17 5FP7 20 7 787 7i 3oLoGT 9 6 88D 180 ICS 14 6 35W4 5 88 80 Eu nnn deeds al E Guam ymo RM Eccas se Let IP Buas 198 morosi 1T ANON Z VRINUSUSI R4nY 19 8 8AN7G 18 806 SI vY4 18 8005 T ee ECCB 8 KMeo yelprse By 25 UAR42 10 8 2759 35 3U4Q 5 8 6AT6 4 6 6EAS 11 9D6 7 6 o0CDOG 30 931A 69 6 xoceo ye EMS0 76 PLS S qqvos 40 UBcil 9 6 Z8000 g9 lbV4G 2 6 8AUS S 6EUT 7 1B2 30 S0EHS 12 sogyc 350 ECcas v bMe oe 85 UBF80 7 Z801U 28 0X4Q 7 GAX4 8 6F23 15 12AT6 4 875 5 6 ECOlas gg M87 11 PLS4 9 8 Gavos soa UBF89 7 lZ900T 12 5Y3GT G SAXSGTIS 8F33 20 12AT7 4i 76 6 Special Vivs ECEB 6 6lEyer SIRE tao 100 UCF80 10 TL4 2 6 5Z4GT 12 687 5 6 6H6M_ 3 j12AU7 5 9 78 5 CV 1031 100 ECFS2 6 6 kyns 2 prios See RIT 8 UCH42 18j6 IRS 6 524 14 6BK7 8 64WA 14 I2AV8 5 8 80 9 CV9339 230 xcrss 156 EX3 2 bi09 30 mis 12 0 vcHsI 9 184 5 6AB7 4 6BAc 4 8 575 7i I2AXT 5 61803 90i IPS TD 750 perso 12 6 EX8 SEX Mi ervesuao ucie 7 195 4 6 GACT 3 6BE6 5 5JGT B I2BAG 6 303 100j Ks01 4 ECF802 12 6 i759 5 P 33 12 60 j UCL83 12 1T4 39 j6AH6 11 6 6BG6G 11 16J6 3 6 12BE6 6 807 9 K305 212 ECU3 1l
79. Wed Tel wiaverley 5 9 Cee earner a 106 Newport Rd pal day Wes MIDDLESBROUGH GLASGOW 2226 Argyle St Half day Tues Tel City 4158 Branches open all day Sats Blackett Street Opp Fenwicks NEWCASTLE Saiz IL O HULL 91 Paragon Street Half day Thursday Tel 20505 M e SENT TO SHOPS 13 Exchange rere Ginean Tel 207a SHEFFIELD 606 YORK HIGH FIDELITY 3 SPEAKER SYSTEM Moderate sise only 25 x 14 x 10in COMPLETE KIT 21 Gns Response 0 20 000 c p s Impedance 15 ohms Performance comparable with units costing Carr 12 6 considerably more Consists ot 1 12in 15 watt Base unit with cast chassis Roll rubber cone surround for ultra low resonance and ceramic magnet 2 3 way quarter section series croas over aystem 3 8 x Sin high flux middie range speaker 4 High efficiency tweeter 5 Appropriate quantity acoustic damping material 6 Teak veneered cabinet 7 Circuit and full instruc tions Terms Dep 4 Gns and 9 monthly payments 45 6 Total 234 Gns DEMONSTRATIONS AT ALL BRANCHES AUDIOTRINE HI FI SPEAKER SYSTEMS Consisting of matched 12in 11 000 line 15 Watt 15 ohm high quality speaker cross over unit and tweeter Smooth di response and extended frequency range ensure surprisingly realistic reproduction 5 5 0 OR SENIOR 15 WATT INC HF126 38 000 LINE SPEAKER CARR 6 6 6 15 0 Corr 5 9 AUDIOTRINE HIGH FIDELITY LOUDSPEAKERS Heavy construction Latest high effici
80. and 962 Sfax 719 in Tunisia Benghazi 674 Tripoli 1052 Beida 1124 and 1250 in Libya Batra 620 and 818 Cairo 773 in Egypt These stations stand out from their neigh bours on account of the Arabic style programming though a few in Morocco Algeria and Tunisia have European programmes with announcements in French Farther east and rather more difficult are Riyadh 588kHz in Saudi Arabia Jerusalem 677 Amman 800 in Jordan Jeddah 647 in Saudi Arabia Beirut 836 in Lebanon Damascus 665 Dayr az Zawr 957 in Syria Ankara Turkey on 1061 Kuwait 1345 in the Persian Gulf Although many of these stations can be logged when using a non directional aerial a MW loop will give an added advantage when DXing to the east The writer has heard Tunis 962kHz on a transistor portable simply by rotating the receiver until interference is at a minimum The out of band Greek station reported recently has been tracked down to Amphissa It is privately owned located near Delphi and signs off daily at 2100 hrs GMT The latest issue of the FBIS list gives the frequency as 1611kHz but variable Reporters to Sweden Calling DXers from Austria Germany Italy and South Africa have heard Amphissa so it ought to be audible in the country in the winter The highest authorised MW frequency is 1602kHz 187 3m which is off scale on many domestic receivers so it is rather surprising to learn of broad casting beyond the band edge The sea path across the north and m
81. and transparent cover with dia mond cartridge or 2025 TC and the very successful DUO type 2 speakers Measuring 171in x 102in x 62in the Duo type 2 speakers are beautifully finished in teak veneer with matching vynair grills They incorporate a 103in x 6zin drive unit and high frequency speaker both of which are of 3 ohms impedance The Duo sneaker syste is also available separately at 66 0 each plus 15 D amp p Complete stereo system 4l plus 2 10 p amp p or with Mk Il Amplifier and Magnetic Cartridge 45 amp 2 10 p amp p High fidelity transistor stereo amplifier employing field effect transistors With this feature and accompanying guaranteed specifications below the Viscount F E T vastly surpasses amplifiers costing tar more Signal to noise ratio 70db on all inputs with vol max Controls 6 position selec tor switch 3 pos stereo and 3 pos mono Separate volume controls for left and right channels Bass 14db at 60 Hz Treble with D P S on off 12 db at 10 KHz Tape recording output sockets on each channel Size 121in 6in 22in in simulated teak case BUILT amp TESTED MkII MAG P U 15 15 plus 10 p amp p Specification same as Mk 1 but with the following inputs Mag P U CER P U Tuner Spec on Mag P U 3mV at 1 kHz input impedance 47K Fully equalised to within 1db RIAA Signal to noise ratio 65db vol max CONTROLS 4 position Switch 2 pos mono an
82. ass 34 15 0 20 0 0 Teleton AQ203 Amplifier E cd 28 7 0 20 0 0 Two full size 30 x 10 x 74 internationally acclaimed Musetce Speakers F ae 38 0 0 29 0 0 BARCLAYCARD CREDIT FACILITIES AVAILABLE FOR NEW AND EXISTING HOLDERS 10 0 70 0 0 OTHER COMBINATIONS OF HI Fl EQUIP MENT AVAILABLE ON REQUEST AND MORE L amp M SENSATIONAL BARGAINS Plinth and Cover to fit most makes of GARRARD TURNTABLES com plete and ready for easy Brand New and Fully Guaranteed assembly with perspex cover of Neutral Smoke 2025TC 817 6 Tint Spindle can be left 75 Carr Paid 40B 990 in position with cover on SP25 10 19 6 ALSO AVAILABLE L amp M SL65B 13 i9 6 Plinths and Covers fully 16 9 6 assembled 85 Carr Paid AP7S L amp M SUPPLIES HAINAULT HOUSE HAINAULT STREET NEW ELTHAM SE9 Tel 01 850 0829 Own Car Park Callers Welcome 618 AMPLIFIERS OF QUALITY AND RELIABILITY at the right price ip i INS PHASE 12 An extremely attractive solid state stereo amp lifer ideal for unit audio use Facilities in clude MAGNETIC and we CERAMIC P U RADIO z ONLY TAPE etc Output 6 E watts per channel Freq Response 40 24 Gns 40 000 c p s 3 dB Hum level7 4 dB s Controls include Input Selector Volume Recommended Balance Bass Treble and Stereo Mono Retail Price Switch Black and silver facia panel with satin silver control knobs Slimline fini
83. bands On 160 metres the feeders may be joined together at the bottom and PREMIER STEREO SYSTEM ONE manual record player unit fitted stereo mono cartri and two matching teak finish loudspeaker systems A The 10 transistor amplifier has an output of 5 watts p tape output socket Controls Bass Treble Volume Brushed aluminium front panel Black metal case with teakwoo available separately if required 14 19 6 Carr 7 6 AURIGA 8 WAVEBAND TRANSISTOR PORTABLE Covers Medium Long and 6 Bhort Waves and includes many features not normally found in this price range 10 transistors and 2 diodes Push Pull output Press but ton dial illumina tion Volume tone tuning and wave change controls Telescopic aerial Uses 6 x liv batteries Sockets for external batteries tape recorder and aerial Elegant black and chrome cabinet Size 11 x 21 x 71 Consists of an all transist idge and moun A sinall but pow reproduction 10 watts per channel music power Inputs for Gram Magnetic and Urystal Tuner and Auxiliary Premier Tape Record output Controls Volume Balance Hass Price 15 Gns P amp P 7 6 Treble Stereo M PREMIER HI FI STEREO PRICE HEADPHONES Designed to the highest possible standard Fitted 2bin speaker units with soft padded car muffs Adjustable headband 8 ohine Impedance Cor plete with fit lead and stereo jack pl
84. f and oscillator sections The if transformers are mounted with the identification spots nearest the centre of the chassis Paxolin strips are secured under the jin holes as transistor mounts four tiny holes being drilled through these through which the transistor leads are passed The transistors should be pushed right down and the shield lead bent over and soldered direct to the underside of the chassis After winding the coils L1 2 and L3 4 and E Sa are secured in position on the chassis with a contact adhesive such as Evostik When winding the close A rear view of the completed receiver Chassis dimensions 8x4x1 deep F T Caps RE IF Gain control xU ve 9V AGC Fig 4 Underchassis wiring of the second converterii f amplifier wound single layer coils it will be found easier to wind five turns or so at a time pushing each five turns down before the next five are wound In this way all the turns of the completed coil are close together and neat Finish with a spot of polystyrene cement or a coating of wax Where d c wiring passes through the chassis or Screened compartments it is convenient and good practice to use fed through capacitors R F wiring can simply pass through holes in the chassis or else feed through insulators can be used These can be made by glueing a short length of sleeving in the hole and passing a small piece of thick wire through the sleeving Wiring in of components can
85. f o on 40 metres followed by a buffer amplifier frequency doubler and power amplifier and how it can be modified for multiband operation Typical valve types are shown Fig 1 If the modifications are carried out over a period the transmitter need not be off the air for any significant time VFO Buffer Amplifier The v f o will usually consist of an oscillator in which the circuit components and construction have been carefully integrated in order to get the maximum degree of stability and working in this case on the 40 metre band The buffer amplifier is a must in order to isolate the v f o from the following stage which can in fluence the stability of the v f o e Output This is particularly so if the follow ing stage is keyed In general the lower the operating frequency of the v f o the better will be its stability However there is no ob jection to tuning the output circuit of the buffer amplifier to the 20 metre band as a first step to im proving the versatility of the trans mitter Fig 2 It is recommended that at a later date the v f o itself be modi fied to function on 80 metres so that operation on 40 metres be comes possible VW PA 20 metres Fig 1 A typical arrangement of a four valve transmitter for the 20m band BSR 4 SPEED SUPERSLIM AUTO RECORD CHANGER Plays 12 10 or 7 records Auto or Manual A high quality unit backed by BSR reliability with 12 months guarante
86. gzai Bios sTvos0 80 UF4l 10 IX2A 6 6AK5 5 6BJ6 8 6 6J7G 5 12BH7 3 6 813 75 K308 19 ECH42 13 liz34 iog 98 180 UFR0 T7 3 1X29B 7 6 6AK8 6 6BQTA 8 9 077M 8 19C8 5 6 8324 5 K337 12 ECH81 59 kros gpg X9 B 6 TTI 81 TF80 6 9 3A4 4 6ALo 9 6BR7 16 6K6GT 8 l2El 17 866A 15 KRN2A 70 ECH83 8 8 kqus 3g PY82 5 6 U25 1j8 jUL41 12 3D6 3 i IGALoW T7j 6BW6 16 6K7 8 6 12K5 10 954 4 6 WLA17A 30 ECH84 7 8 N78 25 PYSS Tj U96 14 8 UL84 6 3Q4 7 6 6AM6 3 JGBW7 18 6K7G 2 I2K7GT 6 9 955 4j 3J 92 E ECH200 12 61 645 6 _ PY88 U27 8 UUs 7 384 6 9 6AN8 10 j 6C4 5 9 6K8G 4 I2K8GT 7 6 956 2j 37 10 EcL8o 8 942 l 7 6 U191 14 UY41 8 6 3V4 8 6AQ3 6 6C6 4 6K8GT 7 8 12Q7GT 5 8 957 6 5022 815 ECL82 6 6 O82 8 PY80 9 6 W301 6 6 UY83 5 9 5B254M 86 6AQSW 9 6CH6 ll 6K25 14 128G7 7 991 6 714AY 4 ECL83 10 6 PABC30 7 6 PYS01 9 6 U801 20 VR105 30 6 5B 259M 35 6A86 6 6CL6 9 9 6L6GT 9 1487 15 1622 17 1725A 10 29 41ft AERIALS each consisting of ten 3ft iin dia tubular screw in sections 11ft 6 section whip aerial ALL OVERSEAS ENQUIRIES AND ORDERS P C RADIO LTD with adeplor to fit the Tin rod insulated base stay Please address to plate and stay assemblies pegs reamer hammer etc 1 170 GOLDHAWK RD W 12 beg iutely Pan d eal complete
87. in place of the normal modern light switch The ivory mounting plate matches modern fittings and the control knob is bright chrome An ON OFF switch is incorporated to control 40 600 watts of all lights except fluorescents at mains voltages from 200 250V 50 Hz Competitive products seli at 4 19 6d our price is 3 4s We also offer at 2 14s a complete kit of parts with instructions enabling you to build this dimmer yourself The circuit uses a miniature RCA triac and a diac triggering device to give complete lity Radio interference suppression is included Post and Packing 1 6d extra Please send Cash with Order to DEXTER amp COMPANY ULVER HOUSE I9 KING STREET CHESTER CHI 2AH Tel Chester 25883 As supplied to H M Govt Departments Hospitals Local Authorities etc igw Bolve your communica Em tion problems with this 4 Btation Transistor Intercom system 1 master and 8 Subs in de luxe plastic cabinets for desk or wall mounting Call talk listen from Master to Subs and Subs to Master Ideally suitable for Business Bur gery Bchools Hospital Office and Home Operates on one 9V battery On oft switch Volume control Complete with 3 connecting wires each 66ft and other accessories P amp P 7 6 MAINS INTERCOM No batteries no wires Just plug in the mains for instant two way loud and clear com munication On off switch and volume control Price 12 12 0 P amp P 9 ex
88. input 10 ranges 01 003 1 3 1 3 10 30 100 300V R M B 4cps 1 2 Mc s Decibels 40 to 50dB Supplied brand new complete with leads and instructions Feren 230V A C 17 10 0 TE 65 VALVE VOLTMETER High quality instrument with 28 ranges D C volts 15 1 500v A C volte 1 5 1 500v Resistance up to 1 000 megohms 200 240v A C operation Complete with probe and instructions 217 000 P amp P 6 Additional probes avail able R F 42 6 H V 50 AUTO TRANSFORMERS 0 115 230V Step up or step down Fully shrouded 150 W 2 2 6 P amp P 3 6 300 W 3 5 0 P amp P 4 6 00 W 4 10 0 P amp P 8 6 1 000 W 8 10 0 P amp P 7 6 1 000 W 8 19 0 P amp P 8 6 7 500 W 415 100 P amp P 29 SOLID STATE VARIABLE A C VOLTAGE REGULATORS Compact and panel mounting Ideal tor con tro of lamps drills electrical appliances etc Input 230 2 0v A C Output continuously variable from 20v 230v 0 26 12 5 10 50 250 1 000 090 v D C 0 504 110 100 500mA 10 0 10uA 6 60 300MA 12 Amp 0 2K 200K 2M 200M Q 20 to 17 bB 19 10 0 P amp P 3 6 TMK LAB TESTER 100 000 O P V iin Scale Buzzer Bhort Ci cuit Check Sensitivity 100 000 0 P V D C 5K Dively AC amp 0 MODEL 5025 57 Ranges Giant 5Stin Meter Pol arity Reverse Switc Sensitivity 50K Vc D C 5K Volt A C D C lta 125 25 1 25 b 10 25 50 125 250 500
89. instructions 7 Gns Carr 7 6 OR FACTORY BUILT WITH 12 MONTHS GUARANTEE 8 19 9 R S C AJ I HI FI 12 14 WATT AMPLIFIER PUSH PULL ULTRA LINEAR OUTPUT BUILT IN TONE CONTROL PRE AMP Two input sockets with mixing facilities High senuitivity 5 valves Independent Bass and treble controla Frequency response 3dB 30 20 000 c s Hum level 60dB Sensitivity 40 millivotts For Crystal or Ceramic PUs High Im pedance mikes For Musical Instruments etc Std AC mains For 3 amp 15 ohm spkrs Complete kit Fmi 10 G instructlons and point to point wiring diagrama Carr 11 6 uns EH Tr genet ED win handled metal cover 85 ice Factory bu gas or Deposit 3 and 9 month ents of 31 Total 217 3 6 iain S kere A R S C COLUMN SPEAKERS ALL TYPES 15 OHMS COVERED IN REXINE VYNAIR IDEAL FOR VOCALISTS AND PUBLIC ADDRESS HI FI CENTRES LTD TYPE C4100 also suitable tor Bass Guitar or Electronic Organ TYPE C488 25 80 WATTS TYPE C4128 50 WATTS Fitted four 8 high finx 8 watt speakers Fitted tonr TE 11 000 line 15 watt Overall size approx 48 x 10 x 5 in Carr 10 speakers Overall size approx 6 x 14 x 9 jn Carr 15j Terms Dep 3 and 9 monthly Terms Dep 4 and 9 monthly payments 39 6 Total 418 18 6 L GNS Payments 88 8 Total 30 6 0 20 GRIS TYPE C4100 100 watts inc four 12 50 watt speakers for conservative rating 48 Gns Extra heavy construction Acoustically filled and pressurised Carr
90. is necessary to move air fast Kit comprises motor tan blades sheet ateel casing pull switch mains connector and fixing brackets 39 8 6 6 post and ins MULTI SPEED MOTOR Replacement in many well known food mixers Six speed are available 500 850 and 1 100 r p from either or both of the nylon sockets where the beaters of the food mixers normally go and 8 000 12 000 amp 15 500 r p m ideal polishing Be first this year SEED AND PLANT RAISING Soil heating wire and trans former Suitable for standard size garden frame 19 6 Post and ins 3 6 I2V EXTRACTOR FAN BY DELCO washer and nut 4way Sway 6 way 8 way 9 way 10 way 12 way Caravan Car or Boat 6 speeds from the main drive shaft This drive Bladed 5 diameter fan inside shaft ia 3 diameter and approximately 1 long heavy duty cylinder with 3 Noe Hr Hh 15 HH Hs Hs 22 x 106 A further point about this motor is that being point fixing flange 52 dla 3poles 6 6 6 6 6 6 6 6 10 6 10 6 10 6 14 6 14 6 230 240v AC DC series wound ita speed may be meter fixing hole Length 4 poles 6 6 6 6 6 6 10 6 10 6 10 6 10 6 18 6 18 6 further controlled with the use of our Thyrister approx 8j Exccptional controller This is a very powerful and useful 4 i 5 poles 6 6 6 6 10 6 10 6 14 6 14 8 14 6 22 6 29 6 A o h bargain 27 6 plus 5 6 post and insurance 8 poles 6 6 10 6 10 8 10 8 14 6 14 6 14 8 26 6 26 8 motor size approx 2
91. meter would do well to connect the pre amplifiers to a 22V battery supply 5 x 41V torch batteries and check them for performance before connecting them to the power output modules and the MU442 power unit Output Modules and Power Supply The power supply unit MU442 is supplied with a 3 pin mains input socket and the leads from this run internally to the mains and earth connections respectively on the printed circuit board inside First remove the cover to obtain access to the mains connections inside which will be as shown in Fig 11a The red lead to what is effectively the 240V terminal is disconnected and extended as shown in Fig 11b to the mains on off switch on the front panel The return lead from the switch is connected to the 240V terminal Two leads are then connected Mains On off switch Original wiring Red Black Green Fig 11 Modifications to the mains input wiring of the MU44z power supply unit W Fig 12 Details of the wiring to the inputs of the power modules together with the socket arrangement on the back of the power supply unit as shown in Fig 11b to the mains neon pilot light These and the leads going to the on off switch should be taken out through the left hand side looking from the rear of the power supply unit Finally comes the connection of the PA25 power output modules to the output from the pre amplifiers via the volume controls VR4 The PA25 modules and MU442 unit are supplied wit
92. musical highlights and sound effects to recordings Will mix Microphone records tape and tuner with separate controls into single output 9 volt BARGAIN FM TUNER 88 108 Mc s Six Transistor 9 volt Printed Circuit Calibrated slide dial tuning Walnut Cabinet Size 7 x 5 x 4in BARGAIN FM TUNER as above less cabinet 7 10 0 FM STEREO MULTIPLEX ADAPTOR For above of general use Ready made with 4 transiators 99 16 6 diodes 69 6 A M BARGAIN 8 WATT AMPLIFEIR 4 Transistor Push Pull Ready built with volume control Dv ARADIO BOOKS w Postage 9d Practical Radio Inside Out i Es Practical Stereo Handbook Supersensitive Transistor Pocket Radio S Radio Valve Guide Books 1 2 3 or 4ea 5 No bea 8 T V Fault Finding 405 625 lines BR Transistor Communication Sets 6 Wireless World Radio Valve Data 10 Transistor Circuits for Radio Controlled Models 7i6 Coil design amp construction 5 99 Circuits for Micro Alloy transistors 120v or 240v AC 1 200 r p m 4 pole 185mA Spindle 0 187 x 0 75in Size 25 8 x 24 x Blin illustrated Post 2 6 BALFOUR GRAM MOTORS 120v or 240v A C 1 200 r p m 4 pole SOmA Spindle i x 8 20 Size 17 6 24x 2 x liin Post 2 6 CALLERS WELCOME Tel 01 684 1665 663 STEREO 8 8 MK 11 HI FI AMPLIFIER KIT SPEC
93. off and tone controls A C mains operation 32 output dimensions 44x44x54 ins app new and boxed Unbeatable at 67 6 post paid or in kit form 59 6 post paid ELECTRONIC INDUSTRIES SHROPSHIRE 4 Longden Green Shrewsbury Shropshire We stock ali those components and materials required by the home Hi Fi constructor jneluding speaker grille fabrics BAF wadding Peerless speaker kits Helme Cabinet Kits cross over net works inductors etc Special offers also available Send 5 x 5d stamps NOW for your copy of our new fully illustrated catalogue catalogue cost refunded against purchases over 10s No callers please mail order ONLY A UDIQSCAN A PRINCES GGUARE HARROGATE YORKS COMPUTER PANELS AT BARGAIN PRICE Few hundred left at 5 each 8 x OC43 or GET 8754 24 OASBI Useful length leads C W O P amp P 6d each Mail order only F amp H Guy Ltd 80 High Street Ware Herts PARAPHYSICAL LABORATORY Down ton Wilts Fascinating international maga zines S A E for list Parcel 20s SERVICE MANUALS for Pre 1958 H M V and E M l MODELS Radio and Record Player Manuals 5 each Television Manuals 7 6 each Send C W O stating model re quired Also limited range of components and spares Send details of your require ments R D I Ltd Chilton Works Garden Road Richmond Surrey WANTED CASH PAID for New Valves Payment by return WILLOW VALE ELECTRONICS 4 The Broadw
94. organ Fully transistorized no valves Proper self contained loudspeaker Fifteen separate keys span two full octaves play the Yellow Rose of Texas play Silent Night play Auld Lang Syne play lots and lots of similar tunes on this real working electronic organ Although it s no theatre organ it s certainly no tiny thing it measures 13 x 10 x 21 Uses standard battery You have the thrill and excitement of puilding it together with the pleasure of playing a real live throbbing electronic organ Take it anywhere play it anywhere Step by step plans ONLY NO PREVIOUS KNOWLEDGE OF ELECTRONICS NEEDED is NONE WHATEVER No soldering necessary It really is as all Transistors loud 5 5 a simple as a b c to make Anyone from nine years upwards can build it easily in one short evening follow speaker personal ing the fully illustrated step by step simply worded instructions BIG DEMAND ANTICIPATED FOR THIS UNIQUE INSTRUMENT at our low low building price ONLY 55 4 6d P amp P for all parts phone knobs screws etc all you need Box size 14 x 10 P R B 2 part il tely Bend only 89 6 4 6 P amp P including case loud speaker transistors condensers resistors knobs transformer volume control wire nuts screws x 2 parts avail separately eno on y 16 4 6 P q simple but fuil instructions etc ete uses standard PP3 battery parts available separately Nicely boxed makes thrilli
95. price ofa postage stamp in the Free Heathkit Catalogue MARINE No previous knowledge of tc Save up to 50 over factory electronics required built equipment The constructional manual supplied with every kit shows X Money saving direct from factory prices you how x Building Heathkit models is so They make excellent i TRENT SPEAKER economic Christmas gifts gee HEATH cese LTD croucester c12 ccc A Schiumberger Company N In block capitals Many other models in wide range Bale FILL IN THE COUPON FOR YOUR FREE CATALOGUE TODAY 51 12A RSC HIGH FIDELITY STEREO PACKAGE OFFERS TAI2 AMPLIFIER 6 5 6 5 Four fully wired units ready to plugin Matching as recommended for optimum performance Send EU 30 SMES 15 15 S A Efor coloured brochure showing other money saving offers x yat in veneered housing watt in veneered housing g Pec RRARD SP25 MK II Player amp GARRARD SP25 MK II Turntable on Package prices apply providing it unit on Plinth Plinth with cover all individual units are purchased GOLDRING CS90 Ceramic P U ih See leaflet Cartridge with diamond stylus ridge with diamond stylus GOLDRING CS90 Ceramic P U Cart al from any branch within 3 months i Cartridge with diamond stylus oud il T PAIR OF STAN Gns I speaker Units WAY I Speaker Carr jj Hl Special Units Special Total Price 3
96. public address Handling 40 watts R M S Cone moulded fibre Freq response 30 10 000 c p s specify 3 or 15 ohms Chassis diam 12in 12fin over mounting lugs Overall height 54in A 10 speaker offered this month for 5 19 6 plus 7 6 post and ins MOTORISED CAM SWITCH Made by the famous meter company Chamberlain and Hookham these have a normal mains 200 240V motor which tirlves a ratchet mechanism so geared to give one ratchet action per minute on a wheel with 60 teeth thus a complete revolution of the cam takes place in one hour The can operates 8 switches changeover and 2 on off thus 48 circuit changes per hour are possible Contacts rated at 15 amps have been set for certain switch combinations but can no doubt be altered to suit a special job Also other switch waters or devices can be attached to the shaft which extend approximately one inch 47 8 p amp ins 4 6 BARGAIN OF THE YEAR MICROSONIC KEYCHAIN RADIO 7 transistor Keychaln Radio in very prettv case size 23 x 2j x liin complete with sott leather zipped bag Specification Circuit 7 transistor superheterodyne Frequency range 530 to 1600 Kc s Sensi tivity 5 mv m Intermediate frequency 465 Ke s or 455 Ke s Power output 40mW Antenna ferrite rod Loudspeaker Permanent magnet type In tranalt from the East these sets suffered slight corrosion as the batteries were left in them but when this corrosion is cleared away
97. signal at i f t 3 The result of these a g c combinations is that a good range of a g c is provided without any of the controlled stages being biased into cut off The purpose of the diode D2 and capacitor C23 is to give the fast attack slow decay characteristic required for s s b and c w Fig 3 shows the signal a g c characteristic of the complete receiver S readings are also shown in the scale relative to signal strength and a g c voltage which may be found useful in adjusting the S meter This follows accepted practice of 6dB per S point On the 160 metre band signals should be given the benefit of another S point as the gain is 6dB down compared to the other bands which have the benefit of the pre selector Construction The second converter and i f amplifier unit is built on a chassis 8 x 4 x lin and the main details of 628 7 0 S Meter WV 1 5 5 QV 52 4N 53 6 0 ByN S4 164V 5 324V 56 5 5 64 N 57 128yV 58 sol 2564Y 59 2 5mV 20dB 25mV F40dB acc 45 Volts DC 4 0 3 5 30 2 5 A G C Reference level l 0 PSN Suv 50V 500V SmV 50mV Signal into aerial socket 20dB steps S markings on graph are approximate Fig 3 The signal a g c characteristic of the complete receiver this are shown in Fig 4 The chassis is made from grade tinned plate about 24 or 26 s w g with end plates of 18 s w g aluminium Screened compart ments are provided for the r
98. that the scale is recessed behind the front panel proper which can also be of aluminium with cut outs to show the scale and S meter A description of the circuit functions construc tional data and alignment information will be given in the following order 1 Second converter and i f amplifier 2 B F O product detector audio amplifier and power supply 3 Pre selector and first converter Second converter i f amplifier As already mentioned this unit Fig 2 is on its own a receiver covering the 160 metre amateur band INDUCTORS L1 20turns pilewound L2 65turns pilewound tapped 6 turns from earthy end L3 55turns pilewound L4 55turns pilewound See Fig 2 for winding details L5 55turns closewound All inductors wound on tin dia formers with dust cores Radiospares 36 s w g enamelled copper wire and shipping in the range 1 5 to 20M Hz the front end of which in the complete receiver becomes the second converter or tunable first i f To ensure a good Q factor in the aerial tuned circuit the aerial is loosely coupled to L2 via L1 and similarly the base of Trl is tapped well down on L2 L1 is returned to the supply line via R1 as this will later carry the supply voltage to the first mixer The r f stage Trl is coupled to the mixer by the wide band transformer L3 L4 This has a relatively flat response over the range 1 5 to 220MHz with a sharp cut off at the ends The oscillator Tr6 is
99. they should work perfectly offered without guarantee except that they are new Price only 24 6 less batterles plus 6 post 6 tor 7 post tree Rechargeable batteries 8 8 palr 1 HOUR MINUTE TIMER Made by famons Smiths company these have a large clear dial size 4 x 38 which can be set In minutes up to J hour After preset period the bell rings Tdeal fnr processing a memory jogger or by adding simple lever would operate micro switch 22 6 3 W TANGENTIAL HEATER UNIT This heater unit i amp the very latest type most eficient and quiet running Is ax fitted in Hoover and blower heaters costing 15 and more Com prises motor impeller 2kW element and IkW element allowing switching 1 2 and 3kW and with therinal safety cut out Can be fitted int any metal line case or cabinet Only need control switch 70 8 Postage and insurance 6 6 24kW model 48 6 plus 6 6 p amp p 2kW model 89 6 plus 6 6 p amp p MICRO SWITCH 5 amp changover contacts 1 9 each 18 doz 15 amp Model 2j each or 21 doz Where postage is not stated then orders over 5 are post free Below 5 add 2 9 8 A H with enquires please Mains Connector A quick way to connect equip ment to the mains safely and firmly disconnec tion by plugs prevents accidental switching on has sockets which allow Insertion of meter with out disconnection cable inlets firmly hold
100. valuable supplementary information 10s post paid AMATEUR RADIO TECHNIQUES By Pat Hawker G3VA A source book for many useful circuits and aerials incor porating the latest techniques in the amateur field Thiru 1970 Edition 208 pages Nearly 500 diagrams RADIO COMMUNICATION HANDBOOK over 22 000 copies sold Now in its second printing The standard work in its field RADIO COMMUNICATION SANDAOQN 832 pages of everything in the science of radio communi cation The handbook s UK origin ensures easy availability of components 69s post paid Obtainable from RADIO SOGIETY of GREAT BRITAIN 35 DOUGHTY STREET LONDON WC1N 2AE When in LUTON BEDS vou must visit the SELF SERVICE RADIO COMPONENTS SHOP 1 200 boxes Ive money veursclf fram a selecti ar of Manufaclurer s surplus stocks 4nd s 9 a m to 5 30 p m every day Closed all day Wednesday URPLECTRONICS 2114 LEAGRAVE ROAD LUTON REDS Many New Models in the FREE HEATHKIT 1971 Catalogue CONSUMER HI FI amp AUDIO Here s the bumper Heathkit catalogue for you Read about the wonder and fascination of kit building see in full colour the world s best values in Hi Fi Radio and even model radio control Get up to date with what s new in scientific instrumentation instruments for test and service in fact there is a Heathkit for almost every purpose in every walk of life A wealth of informa tion is all yours for the
101. very please with It indeed have used other communication receivers in my Mr W Moris nereti Avenge ROME dan APA TN xcellent time and the CR70A is beyond my expectation and was well vality and gius vet C DAR Pr di ee P e worth waiting for My friends are amazed at its performance a pertormance o eects Mr F Rose Oak Lane HIGH WYCOMBE Bucks Mr D Foster Wansford Road DRIFFIELD Yorkshire You can be proud of your equipment your name is held in great lam very pleased with the quality of the parts and consider this esteem by Radio Amateurs fine set excellent value for money More extracts next month Send 10d stamps for literature on CODAR COMMUNICATION EQUIPMENT Start your own Short Wave Station now and listen to world wide commercial and amateur stations shipping trawlers Ship to shore telephone Lifeboat Services Met stations etc etc G copaAR RADIO COMPANY 2 0 0 2 E3 UNIT I MEADOW ROAD INDUSTRIAL ESTATE EAST WORTHING SUSSEX 643 who wants a 2 000 p a opportunity in th dynamic new Compiiter industry NOT as a PROGRAMMER but an OPERATOR No maths and no special education Now for the first time anybody can train outside the computer industry for a lucrative career as a computer operator with actual experience on an Eduputer Who created Eduputer The internationally famous company Programming Science International They developed it to the specific requirements of the massive Ne
102. where there are large Hi Fi and component stocks at the keenest prices including GARRARD 1025 Autochangers com plete with GARRARD STEREO CARTRIDGE 7 GNS MAGNETIC CARTRIDGES Goldring 800H 7 GNS shrine AT33 7 10 0 Both listed over 10 7 Queen Street 3280 601 JANT fom EEG MODEL 5025 Send your name and address now to receive immediately the new 1971 Edltion of LASKY S famous Audlo Tronlcs pictorial catalogue larger and more comprehensive than ever before Packed with 1000 s of items for the Radio and HI Fi enthusiast Electronlcs Hobbiest Serviceman and Communicatlons Ham Covers every aspect of HI Fi including Lasky s budget Stereo Systems and Package Deals plus Lasky s amazing money saving vouchers worth over d your name and address and 2 6 for post and inclusion on our regular mailing list THORN PYGMY PLUG IN A compact pygmy relay on an 8 pin base with D P D T contacts rated to 10A Some type are 3 P D T on an 11 pin base RN TYPE Contacts Base Coil Voltage 215048 P D T 8 pin 48V AC DC 235004 Hi A 8 pin 40V DC 215060 P D T 8 pin 0V AC DC 305030 P D T 11 pin 60v DC 205024 BID 8 pin 24V DC 215042 P D 8 pin 42V DC Others available in limited quantities LASKY S PRICE 12 6 post sie Lasky s ceo coo c12 Exclusively made for us in U S A Great Savings Each Post Five for Ten for C 60 7 6 1f 33 2 62j 3j C90 12 6 t 56 2 110 3j C120 17 1 75 2j
103. 0 3 Way Speaker System Teak Cabinet size pp 15 Ready wired with 5 pin Din or Phono 10 6 extra 21 x 114 x 93 20 Watts Peak each 11 19 6d p p 10 For any other Deck 3000 2025TC Prices for good not listed sent by return add price of Plinth and Cover to Deck and add 15 p p of post S A E please Send P O Order Cheques etc to AUDIO SUPPLIES Callers welcome 50 STAMFORD HILL LONDON N 16 Phone 01 806 3611 Open Sun 10 a m to 2 p m Mon to Sat 9 30 to 6 p m Thurs 1 p m 672 M amp B RADIO 38 BRIDGE END LEEDS 1 Telephone 0532 35649 VHF FM MW LW c gS TRANSISTOR RADIO BRAND NEW 10 tran sistor plus 4 diode table model of well known British manufacture The highly polished wood cabinet speaker and pre assembled chassis are supplied separate and only require fitting to gether and the 2 speaker connections making CHASSIS amp CABINET 9 10 0 SPEAKER 25 carr paid STC STEREO MONO HEADPHONES Brand new lightweight high quality comfortable padded headphones for stereo or mono use Weight 10 oz 20 c s to 20 Kc s 300 ohms per earpiece Supplied with details of matching circuit for 15 ohms using only 3 resistors 54 plus 4 pp 12 VOLT TRANSISTOR INVERTERS 12vdc input 270vde at 150mA approx output Transformer 2in x 2in x l in mounted on aluminium case 1gin x 2zin x 4in Weight 150z 65 plus 4 pp TRANSISTOR MODULATOR PRE AMP PANEL BRAND NEW 4 transist
104. 0 20 All 10 each pack device in the Pak The devices themselves are normally unmarked MPF105 8 6 BRAND NEW FULL TO MANUFACTURERS Price each S SPECIFICATION 1 24 25 99 100 up BI PA K Enn L 0 W co ST C S BP709 Operational Amplifier dual in line 14 pin pack s age 8N72709 and similar to MIC709 and ZLD709C 10 6 9j 8 This i a high performance operational amplifier with high impedance differential inputs and low impedance output BI PAK Semiconductors now ufer you the largest am most TTL INTEG RATED CIRCUITS popular range of 1 C s available at these EXCLUSIVE LOW PRICES TTL Digital 74N Berles fully coded brand new Dual in line plastic 14 and 16 pin packages CA3020 RCA U S A LINEAR INTEGRATED CIRCUITS Audio Power Amplifier 30 each 6 Qo Qo Qo 0x On Qo Cb c6 Manufacturers Fall outa out of apec devices including functional units and part functional but classed aa out of spec from the manufacturers very ridged specifications Ideal for learning about 1 C s and experimental work on testing some will be found perfect PAK No PAE No PAK No DAE sere Des Prsceandiaty trices U1C00 5x7400N 10 UIC42 x 7442N 10 ULCRO 5 x 7480N 10 ger Bon i wecription se cm A UICO 60x7401N 10 VICIO 5x 7450N 10 UIC89 5 x 74B2N 10 a j j i 4 U1002
105. 0 a Total Price 54 Gns Carr 25j Or Depoiiy TS ang 2 mental e payments 0 4 ota gns oS Trans Tipuon Turntable Transparent Plastic Cover 3 gns X Shure or Goldring Magnetic P U ATTRACTIVE TEAK or AFRORMOSIA extra Cartridge AS ABOVE BUT WITH GAR Pair of Stanway II VENEERED CABINETS and PLINTHS RARD 3000 AUTOCHANGER Loudspeaker units 92 Gns bs TERMS AVAILABLE ON ALL PACKAGE OFFERS AND SONOTONE 9TA Ceramic Special Total Price Cartridge in lieu of Carr SP25 and CS90 49 Gns 25 RINE A55 HIGH QUALITY STEREO SYSTEM 3 Or Deposit 6 and 9 monthly B PAIR OF payments 5 14 0 Total 57 6 0 LOUDSPEAKER UNITS Trans Plastic cover 3 gns extra S ener Size approx Ml Mol M TT RS CREDIT TERMS 13 x 74 x 8i ins price 39 Sie complete ilabl h 5 BASS VOLUME STEREO ij P Gns s RITS of pares excepted BRA Operation en Wu ars standar 250v A C Luxurious Teak V Finished Cabinets T t Terms Deposit 5 and 9 mains Output rating plastic tinted cover Included tor ats anit Bilver monthly poss 4 gns INTEREST CHARGES REFUNDED On Credit Bales settled in 2 months LH F M finished facia plate and matching control knobs Total 44 18 0 A REALLY SURPRISING STANDARD OF QUALITY IS OBTAINABLE FROM THIS COMPACT LOW PRICED SYSTEM HIGH FIDELITY LOUDSPEAKER UNITS credit terms available Cabinets latest style Satin Teak or Afrormosia veneer Acoustically lined or filled acoustic damping Ported wher
106. 0250 40361 40362 40405 40408 40430 Tolerance Range 5 5 10 5 10 2 10 41 209 022 b 59 12Q 10K Q 5 12 Q 10K Q Codes 3 carbon film high stability low noise MO metal oxide Electrosil T R5 ultra low noise WW wire wound Plessey Values E12 denotes series 10 12 15 18 22 27 33 39 47 56 68 82 and their decades E24 denotes rerien as E12 plus 11 13 16 20 24 30 36 43 51 62 75 91 and their decades INTEGRATED CIRCUIT AMPLIFIERS SINCLAIR IC10 complete with instruction book giving amplifier circuit details and range of applications 59 8 nett Components pack for stereo inc mains transformer controls etc 4 15 0 nett PLESSEY SL403A Now only 42 6 nett 3W into 7 5Q for 18V supply Application data sent with two more S ee EE NEA WAVECHANGE SWITCHES LONG SPINDLES 1P 12W 9P 6W 3P 4W 4P 3W 4 9 each SLIDER SWITCHES D P D T Sj each ae ee Hn PH eo s NEON INDICATOR LAMPS all 200 250V Square bezel red only Round chrome bezel red amber clear Toggle switches 250V a c 1 5A chrome dolly and chrome milled nut 8 P 8 T 3 8 S P D T 4 0 D P D T 5 9 8 P D T centre off 5 3 9 4 9 each S DeC s put an end to blrdsnesting Components just plug in Saves valuable time Use components again and again S DeC 70 points only 25 Compact T DeC increased capacity may be temperature cycled T DeC 208 points only 50 post free Full range stocked ELECTROVA
107. 0C74 6 8 Quantity Prices on Application 2No217 5 6 2N4002 2 6 A F114 s BF178 10 6 GETIN Ae OC75 ye General Electric 2N2218 68 2N4244 9 6 AFIIS j BF179 JR GETIT 0076 PA222 87 6 PA246 62 6 Our stocks and range of LC s are 2N2219 j 2N4205 8 6 AFIIG 5 BFI80 7 EETII9 4 OC77 8 PA230 92 6 PA263 46 continually expanding aud we invite n0 oc E NU Uu E EE d M uL IUE 2N2292 8 2N4287 36 AF119 4l BF185 E CRT oss P 37 6 thusiasts and Industrial users 2N2287 21 6 2N4288 8 AF124 4 6 BF194 ET887 B4 7 i 2N2297 6 2N4289 8 6 AF125 4j BF195 4j GET889 4 6 OCI39 6 6 MATCHES ace FIBI e TRIACS 2N2303 5j 2N4290 83 6 AF126 4j BF196 8 6 GETS90 4 6 OCI40 6 6 TA A263 15 6 FJHI4l 17 6 SC41D 6A 400V 2N9368 5 2N4991 39 6 AF127 3 6 BF197 8 6 GETS96 4 6 OC170 6 TAA300 35 FJHI61 17 6 25 2N2369 3 2N4292 2 6 AF139 7 6 BF198 8 6 GET897 4 8 OCI71 6 TAASIO 25 FIJHI7 18 8 SC41B 6A 200V 2N2369A 3 8 2N4303 9 6 AF178 8 6 BF200 10 6 GET898 4 8 00200 7 8 TAA320 14 8 FJH991 17 8 22 2N2410 8 6 2N5027 10 8 AF179 14 6 BF224 4j MAT100 6 OC201 9 8 TAA350 35 FJJIOI 27 6 2N9483 5 6 2N50298 11 6 AF180 10 6 BF225 4 MAT101 6 OC202 12 6 TABI01 19 6 FJJi21 37 8 40512 6A 400V 2N2484 6 6 2N5099 9 6 AF239 8 8 BF237 4 6 MAT120 6 OC203 8 6 TADLIO 89 8 FJJ14l 89 6 88 2N9539 4 8 N5030 8 8 AF279 9 6 BF238 4 6 MATI 1 6 OC204 8 6 TAD100 39 6 Aue e mam e Am CUP Eus ge Nus off sow e ftem BOD p T 2N2613 7j 9N517 8 AFZ11 d 3 2N2614 2
108. 1 ING 250 0 250v 2a 0 5 6 3v Za 200 0 250v 100mA 6 3v 4a 0 5 6 3v 3a 300 0 300v 100mA 6 3v 4a 0 5 6 3v 3a Terms Deposit 8 and 9 montbly payments 6 10 6 Total 57 14 6 Treble controls Current valves Peak output rating Strong Rexine covered cabinet with handles Attractive black gold P V A facia Neon ndicator Total 22 18 0 Carr 12 6 L1313 x 8 10 Watt Lig 12 20 WATT 9 tone Rexine and required high flux speakers for 8 19 9 Carr 15 28 Gns vocatists gram radio tape Peak Output rating 55 Gns Four Jack inputs and two Volume Controls for simul Deposit 13 4 9 and 9 monthly payments of 5 11 9 Total 604 g ns ately controlled inputa 4 Beparately controlled 5 Bass and Treble Con cai die ond trois Output for For fuller details of Phase 29 Gns Carr Free qud against damage from accidental shorta NE UL POWER LO F All power ratings are R M R continuous 2 years guarantee LOUDSPEAKERS 15 60 Watt 12 5 18 100 Watt dran AE Dual Cone 15Q 12 18 0 Dep 22 and 9 n Electronic Organ Total 12 2 6 Dep 6 and 9 monthly pymnts 98 8 paymenta 13 C Aid 30 LI 30 20 000 c s All high grade components Valves EF86 EF86 phones Designed for Clubs Schoola Theatres Dance Halls or ated volumecontrola so that two separate inputs such aa Gram and Mike can be mixed 200 250 Yo Or factory built with EL34 output valves and 12 montbea guarantee for 18 gne
109. 1 9 Unijunction 26383 Bj ACY36 5 100 1 6 25 8 9 2N404 4 6ACY3O 11 500 1 3 100 7 6 2N696 3 8 ACY40 3 500 6 9 2N697 8 8 AD 40 10 AFI39 6 jamma 2N698 8 8 AD149 10 A j 2N706 P ADISD 7 8 Siemens N Hits AFI86 8 i 2NT00A SieADISS 7 EMPPIO io 4 4 6 Mullard x fe 2NT07 B 6 AF10 12 6 MP 105 2N7038 8S AFll4 6 8 0A5 500 3 9 100 6 i 2N914 4 6AFIIS 6 OA7 500 5 i 2N916 2N918 1 6 A 1 6 A 2 24 3 4i 1 6 A 18 8 49 8 4j 4 6 5j 6 4 6 4 6 7 8 AAZIT AC126 2 6 AC127 ACI28 ACI 3 1 9 ACI4 ACIAD ACIT6 LACIB7 AC188 ACYIT7 ACY21 AFLIG AFII7 NEW LIST AZ12 AZ13 nPYIO BSX20 BSXe21 ai 2 6 2 5 5 Z 10 5 4 Ma 3 ar 5i e 8 Bi 19 6 BSY50 BSY53 4j 4 8 QAY OA10 6 6 5j DRAND NEW FULLY GUARANTEED TRANSISTORS SEND FOR NEW PRIGES INTEGRATED CIRCUITS Type t 12 25 UL9I4 8 6 7 9 7 3 UL923 12 6 11 9 11 SL403A 42 5 41 40 MCI303 52 6 48 45 100 500 6 37 6 40 MC1304 55 50 47 6 PA246 52 6 48 45 2N3055 15 Mullard I5watt Oci70 5 42 6 40 2N3819 7i Texas F E T y 9 BY 26 3 2N919 4J AF118 12 0 0447 2N920 Bj AV1 4 Fh OA70 Mullard 800v 9N922 8 6 AF125 OA7I i Imp fius 2N930 5 6 A F126 0473 4 6 2N1131 e A
110. 10 GOODMANS 3000 7714 7 5519 6 ARENA HT 20 311 0 GRUNDIG TK 124 4418 0 PHILIPS RH78 7419 6 54 19 6 ARENAHT 26 7815 0 6 GRUNDIG Tk 148 4919 6 PHILIPS RH790 125 0 0 10119 6 B amp W DM3 63 0 0 MARCONI TK 4218 St 57 12 8 PIONEER KX330 AM FM SW 78 12 4 62 19 6 B amp W P2H eo 0 9410 0 H Record ereo o tape PIONEER SX770 AM FM 160 8 6 129 19 6 B amp W DM1 32 0 0 PHILIPS 290 Caese t 89 11 0 PIONEER 5X090 AM FM 194 14 8 155 0 0 CELESTION Ditton 10 21 3 2 6 Record b Radic TELETONF 2000 7510 0 419 6 CELESTION Ditton15 29 0 0 JB ceca E ao TELETON7AT 10319 0 85 0 0 CELESTIONDitton25 5917 0 s SHINES eons Casse ge cod TELETON R4200 5115 0 39 19 6 DULCI AS 3 8 8 0 6 A a SIOR TWIN Tracky TELETON CR 10T 3915 0 2919 GOODMANS Majesta 57 0 0 t P eeu da 39 0 0 TELETON TFS50 7510 0 49 19 GOODMANS Maxim 20 7 9 0 PHILIPS Naa rac 4910 0 TELETON7AT20 105 0 0 79 19 6 GOODMANS Mezzo I 30 18 0 s 4 track d TELETONI0AT1150w RMS 160 0 0 109 0 0 GOODMANS Magnum K 40 2 0 6 PALIPS OD 87 0 0 TELETON MX990 with GOODMANS Marimba 24 0 1 6 IE 407 Stereo 105 0 0 LETON MAS Ke EA AE GOODMANS Mambo 2 5 6 H PHILIPS 4408 Atk stereo 139 0 0 TELETON R8000 with GOODMANS 3005 pair 25 0 0 6 EIL IBS N4308 8010 0 speakers 63 5 0 49 1
111. 10 0 p p 7 6 1 Full details and complete range in catalogue SLIM POCKET TEST GEAR SIGNAL INJECTOR 35 p p 1 6 SIGNAL TRACER 29 6 p p 1 6 Gros NEW WORLD S LOWEST COST STEREO MAGNETIC CARTRIDGE O P 7mV 20 c s 20 Kc s Diamond Stylus Fits most decks Recommended for Quality and Performance Price 79 6 Model 940 Stock List No 16 17 FREE on request BEST VALUE IN U K Choose from 100 complete stereo syscems Complete range of individual units also in stock Demonstrations all day Visit the new Hi Fi Store 100 STEREO SYSTEMS LOW CASH AND CREDIT HP PRICES Credit terms from 30 purchase callers only HENRY S neY S FOUR ELECTRONICS CENTRE HENRY S LATEST CATALOGUE New print Now 350 pages 6th Impression on COMPONENTS TEST GEAR HENRY S RADIO LTD EQUIPMENT MODULES xk SPECIAL OFFERS ETC ETC Everything for the constructor Complete with 0 value discount voucher for use with purchase Price 7 6 p p 2 WHY NOT SEND AWAY TODAY NEW s page SEMICONDUCTOR LIST FREE no 36 new ranges and a few circuits n YOU CAN SAVE 25 rana new GARRARD Post 7 6 COMPLETE LIST FREE ON REQUEST AND GOLDRING SP25mkll 10 19 6 AP75 16 19 6 SL65B 14 19 6 SL72B 25 GL69 22 SPECIAL Above with Sonotone 9tahc diam vd d 2 with magnetic add 70 with Goldring G800 add 7 10 0 Also Fitted with 9tahc diamond 2025TC 9 15 0
112. 125 10 125 16 160 2 5 200 6 4 200 10 250 4 320 2 5 320 64 400 4 500 2 5 LARGE CAPACITORS High ripple current types 1000 25 5 6 1000 50 8 8 1000 100 16 8 2000 25 7 4 2000 50 11 4 2000 50 11 4 2000 100 28 500 64 15 5 2500 70 19 8 6000 25 12 6 5000 50 21 11 5000 100 58 3 10000 15 17 10000 25 24 6 10000 50 44 10000 70 61 MEDIUM RANGE ELECTROLYTICS Axial leads 50 50 2 100 26 2 100 50 2 6 250 25 2 8 330 26 9 6 250 50 8 9 500 25 3 9 500 50 4 6 1000 25 4j 1000 50 8 2000 25 6 SMALL ELECTROLYTICS Axial leads 47 10 47 25 6 50 l ea 10 10 10 25 10 50 33 10 60 10 1 ea 22 25 25 50 47 25 100 10 220 10 1 8 ea ENAMELLED COPPER WIRE even No 8 W G only 2oz reels 16 22 8 W G 4 3 24 30 S W G 5 32 34 8S W G 5 6 36 38 B W G 6 8 4 oz reela 16 22 8 W G only 7 6 ptifier in modular kit form 12 watta per channel 38 9 25 watts 58 15 Cabinet klt only 8 These prices nett As recently reviewed in Hi Fi Sound BAXANDALL SPEAKER SYSTEM Designed by Peter Paxandall Superb reproduction for ita size Handles 10 watts with ease Uses ELAC 15Q 59RM109 speaker Unit Kit 18 12 nett built 210 8 6 nett MAINLINE AMPLIFIER KITS RCA 8UGB designed main amplifier kits Input rensitlvity 600 700mV for ful ontput into 8N Power Kit price Sultable unreg including power supply coniponents kit 168 nett 190 nett 210 nett 252 nett 12W 25W 40
113. 139j 3j U S A Cassette head cleaner 10 6 Post 1 Post 1 each five for 2 ten for 3 COMMUNICATION RECEIVER A short wave receiver exclu sive to Lasky s at a real econ omy price Four valve line up using one each 6BE6 6BA6 6AV6 and 6ARS5 valves gives highly sensitive reception and powerful gain Switch sel ected SW frequency range cover 1 5 to 30MHz in three separate bandspread ranges and full AM medium wave band cover in one range 550 1 600kHz Reduction drive tuning with hair line cursor Controls include volume on off BFO Band selector Power on Indicator lamp External antenna connections and mains fuse at rear Internal speaker plus standard 5mm jack socket for phones on front For 220 240V a c mains operation Strong metal cabinet finished in grey crackle with anodised silver tront panel Size 95 x 53 x 5zin Complete with mains lead and full instructions LASKY S PRICE 13 13 Post Oo 7 This meter kit by TMK offers the unique opportunity of building a really first class precision multimeter at a worthwhile saving in cost The cabinet movement and range selector mounted in position is supplied with the meter scale The highest quality components and 1 tolerance resistors are used throughout Supplied complete with full constructional circuit and operating instructions 20 000 O P V Multimeter Features MODEL 200 24 measurement ranges with mirror scale Large 3 x 2in meter Full l scale accuracy
114. 16 x 10 x 9 in Modern Scandinavian fluted front design for Mini Module 5 ron 276 HI FI STOCKISTS CUSTOMERS FREE CAR PARK 337 WHITEHORSE ROAD CROYDON Open 9 6 p m Wednesdays 9 1 p m Saturdays 9 5 p m ALL MODELS BAKER SPEAKERS IN STOCK BAKER I2in MAJOR 9 ges 80 14 500 c p s 12in i double cone woofer and tweeter cone together with a BAKER ceramic magnet assembly having a flux density of 14 000 gauss and a total flux of 145 000 Maxwells Bass resonance 40 c p s Rated 20 watts Voice coils 3 or 8 or 15 ohms Post Free M m Module kit 30 17 000 c p s with tweeter crossover baffle and instructions I l l 0 0 BAKER GROUP SOUND SPEAKERS 8 or 16 ohm Group 25 Group 35 Group 50 12 inch 12 inch 15 inch 25 watt 1 25 watt 9 50 watt l 9 pe d oh TE OO TEAK HI FI SPEAKER CABINETS Fluted wood tou For 10 or 12in round Loudspeaker 9 0 0 For 18 x Bin or Bin round Loudspeaker 5 0 0 For 10 x Gin or 64in round Loudspeaker 4 0 0 LOUDSPEAKER CABINET WADDING TWO WAY XOVER NETWORK 3000 c s With variable tweeter attenuator giving accurate high low frequency balance Mounted on panel 5tin x 4in with control knob tweeter and woofer leads and in 38 5 put terminals Suita ble for 3 to 8ohm impedance 2i Horn Tweeters 2 l kc s 10W 8 ohm or 15 ohm 29 6 De Luxe
115. 19 15pF 5 poly C5 250pF 5 poly C20 0 1uF ceramic C6 250pF 5 poly C21 0 1uF ceramic C7 0014F ceramic C22 0 1uF ceramic C8 1000pF poly C23 100pF 5 poly C9 0 14F ceramic C24 100pF 5 poly C10 O 1 amp F ceramic C25 100pF 5 poly C11 0 5pF C26 2200pF poly C12 0 14F ceramic C27 1000pF poly C13 O 14F ceramic C28 0 01nF ceramic C14 10pF 5 poly C29 0 01uF ceramic C15 10pF 5 poly C30 100uF 12VWielec These low value capacitors are obtained by using high value resistors 4 7 MQ VC1la b 180 180pF ganged Jackson Type F SLF TC1 2 30pF trimmers part of VC1a b Semi conductors Tr1 BF167 Tr4 BF115 Tr BF115 Tr5 BC108 Tr3 BF115 Tr6 BF115 Di OA202 D2 OA202 D3 5 6V 250mW Zener IF Transformers 1FT 1 T41 1E Weyrad 1FT 2 141 2E Weyrad 1FT 3 T41 2E Weyrad 1FT 4 T41 3T Weyrad Miscellaneous Feedthrough capacitors 8 Cord drive with 31in drive drum and two in pulleys Chassis 8 x 4 x 1 in see text Tag strip 16 way receiver and the scale should be initially calibrated from 1 5 to 2MHz with the aid of the signal generator in 100kHz steps which can be sub divided into 10kHz steps if desired Note The cores of Ll 4 and L5 must each be treated with a core locking compound or high viscosity grease before they are screwed into the coils In addition the core of L5 should have a thin rubber band screwed in with it TO BE CONTINUED 630 NEXT MONTH IN PRACTICAL WIRELES FREE WALL CHART No 2 In t
116. 201 14 6 30L2 11 6 DF96 7 ECH35 5 6 EZ81 4 8 PCLS6 8 3 U329 14 6AQ5 5 DK32 6 9 ECH81 5 9 KT61 9 3 PFL20011 8 UABC8O0 6 6F23 13 6 DK91 5 6 ECL80 7 6 KT66 18 6 PL36 9 3 UBF89 6 8 6F25 12 DK92 8 3 ECL82 6 8 N78 17 PL81 9 3 UCC8D 7 8 25L6GT 4 6 DK96 7 3 ECL86 7 6 PC86 9 9 PL82 5 9 UCHB81 6 6 30C18 12 9 DL35 4 9 EF39 4 6 PC88 9 9 PL83 6 8 UCL82 6 8 30FL1 12 6 DL92 5 9 EF80 4 6 PC97 7 6 PL84 6 UF89 6 30L15 12 0 DL94 6 6 EF85 5 9 PC900 7 PL500 12 9 UL84 6 8 30L17 14 6 DL96 7 3 EF86 6 3 PCC84 6 8 PL504 18 UY4 7j 30P4 12 DY86 5 3 EF89 4 8 PCC89 9 8 PY32 10 UY8 5 8 30P19 12 DY87 5 8 EF91 2 6 PCC189 9 8 PY33 10 Z77 3 9 30PL1 12 8 EABC80 6 3 EF183 5 6 PCF80 5 11 PY81 5 30PL1314 EB91 2 EF184 6 PCF86 389 PY82 5 30PL1413 6 ERC33 7 9 EH90 7 3 PCF801 6 6 PY800 7 CCH35 13 EBF89 6 EL33 9 8 PCF802 8 9 PY80l 7 Postage on 1 valve 9d extra On 2 valves or more postage 6d per valve extra Any parcel insured against damage in transit 6d extra Office address no callers GERALD BERNARD 83 OSBALDESTON ROAD STOKE NEWINGTON LONDON N 16 RSGB Amateur Radio Call Book 1971 Edition now available Including details of new call signs issued by MPT up to 31st August 1970 and more than 2 100 changes of address compared with the 1970 edition 128 pages including 14 pages of
117. 30 p m Open until 8 p m Wednesday Thursday amp Friday Rec Retail Comet Rec Retail Price Price COMET for SERVICE DEPOTS ie PR STEREO AMPLIFIERS at LEEDS GOOLE LOWTHER Ideal Baffle 35 10 0 29 17 6 ARMSTRONG 521 56 0 0 46 0 0 after sales WAKEFIELD Acousta with PM7 53 0 0 4519 6 DULCI 207 A 5 0 0 17 0 0 DONCASTER QUAD Electrostatic 66 0 0 5219 6 DULCI 207M 30 0 0 2019 0 service HULL and Piet c n AED M2 Maxamp 54 0 0 39 19 6 THROUG AK so 18 0 0 1419 6 GOODM vs SoA NOL 39 48 8 OUGHOUT THE U K BRIDLINGTON WHARFEDALE Speakers LEAK Stereo 30Plus 53 0 0 4219 6 Airedale 6910 0 5 19 ALI ME 59 10 0 4719 6 fec Retail Comet Benton ce lt 09 00 417 LEAK Stereo 70 uper Linton U 2 LEAK Stereo 70 in teak case n 10 Ess 9 GARRARD SP25 fully wired with Goldring G800 Melton S e 28 10 o in is H LINEAR LT 66 210 0 1619 6 magnetic cartridge complete with base plinth Dovedale 3 3910 0 29 19 6 LL Stereo Amp Lo 23 10 0 16 19 6 and cover Special price 20 19 6 Rosedale ff 5910 0 46 19 METROOUNL sT20 7 35 0 O 28 ts 6 GARRARD SP 25 Mk It 1511 4 10 10 6 UNIT 3 Speaker Kit 1119 6 910 0 PHILIPS RH S91 1 9 l 73 0 0 5519 6 GARRARD AP 75 23 16 0 1710 0 UNIT 4 Speaker Kit 16 00 13 5 0 BHEIBSRHESO 55 27 di v EN i2 6 ARRARD SL 55 131
118. 3000LM 9 15 0 Model 50 9 15 0 Plinths Covers Standard 99 6 p p 4 6 De luxe 8 10 0 p p 6 SL72B type 8 10 0 p p 6j GL69 Type 9 15 0 p p 6 6 Goldring GL69 with pinih and cover and G800 cartridge usually 51 39 10 0 p p 12 6 NE watt and B watt RMS A SILICON AMPLIFIERS es LOOK AT THE SPECIFICATIONS 0 3 Distortion at full power idb IIc s to 40kc s at full power Response Idb Iic s to 100kc s PA25 10 Silicon Transistors Differential input 25watts rms into 8ohms mV input Size only 5 x 3 x 2 4 hole fixing 2watts into I5ohms Supplied with edge connector and harness PASO 12 Transistor Version 50watt rms into 3 to 4ohms MU442 Power supply for one cr two PA25 or one PASO PA25 7 10 0 amp PASO 9 10 0 MU442 6 SELF POWERED NEW PREAMPLIFIERS Mains operated slim design Pre amplifiers for use with any Power Amplifier All Silicon FET Transistor designs Capable of driving up to 4 PASO Amplifiers Push Button selection All facilities MODEL FETI54 STEREO PREAMPLIFIER Inputs for mag Pickup Tuner Aux Tape in and out Response 20 c s to 30kc s Output adjustable up to volt 20dB Boost or Cutout Controls Slim design Size 12 x 5j x 12 Price 16 10 0 MODEL FET 9 4 Mono Preamplifier with built in MIC MC XEC Inputs for all Crystal and Ceramic cartridges Tuner Tape in and out OJP and Response as FETIS54 Size 104 x 4 amp x 12 Price 12 10 0
119. 3047 28 2N1507 39 6 2N3860 6 ACYI7 5 6 BDY10 27 6 BSYs2 10 6 OC96 5 8 CA30190 17 CA3030 28 CA3048 AlJ 2N1613 5 2N3866 20 ACY18 5 BDYIL 32 6 Bayo 16 0C28 12 8 CA3020 26 CA3035 25 CA3049 82 2N1631 2N3877 j ACYI9 b i BDYIl7 B8Y95A ocz9 12 6 da un ication ah A 2N1632 6 2N3877A 8 ACY20 5 BDY18 35 BSW41 8 6 OC30 Been pate and eee en eheeis OP ty NA OLA DATA S HEETE 2N1637 6 2N388A 19 8 ACY21 8 BDY19 39 6 BSW70 5 6 OC35 10 MC724P 13 8 MC799P 13 3 2 per Type 2N1638 5 6 2N3900 7 6 ACY22 4j BDY20 22 6 C111 15 OC36 12 6 MC780P 49 5 MC838P 109 8 We can now offer the whole range 2N1639 5 6 2N3900A 8 ACY28 4 BDY38 19 6 C424 5 6 0038 10 6 MC788P 18 6 MC1303P 654 of Motorola I C s and most of the AN CS INN QC AVAL SC BDYOL RAS Clo E CIS RO MENS MS MOIR 97 BCA Milari EE s r a s 90P sj e CR 2N1893 7 8 9N3004 T ACY44 8 BDY62 20 C744 e Vocis e ta Merroacee PROCLI e nana Cope REUS 2N2147 18 8 2N3905 7 6 AD140 10 6 BFIl15 5 DIG6P1 7 6 OC45 2 6 Fairchild 1 5 6 11 12 2N2148 11 6 2N3906 7 8 ADI49 11 6 BF117 9 6 D16P2 8 OC45 3 1900 Buffer 8 6 8 7 8 2N2160 11 6 2N4058 3 6 ADI50 12 6 BF163 7 6 DI16P3 7 6 OC70 3 1914 Dual Gate 8 6 8 7 6 2N2193 8 2N4059 2 ADI6 7 8 BF167 5j DI6P4 8 OC71 2 8 L993 JK Flip Flop 12 6 11 9 uy 2N2193A 8 6 2N4060 2 6 ADI62 7 6 BF173 8 6 GET102 6 OC72 2 6 L709 Operational Amplifier 21 19 6 18 QN2194A 8 2N4061 2 6 AF106 8 6 BFI77 6 6 GETII3 4
120. 30FL1 185 9002 4 6 ESOCC O1 191 RF92 2 6 PCF801 9 9 OAZ202 to OC81D 8 INS21A 21 40636 29 BFY52 4 6 SD988 8 8 ees 2 3K12 18 6 9003 10 g7 BESS 5 PCF802 9 9 OAZ206 8 6 OC81DM 3 INS23A 20 40068 27 B805 6 vaoa 7 9 6297 9 30FLI3 8 3 9004 2 6 7 m URBC iu Ms 6VEG 3 6 30FLI4 15 6 EF183 6 6 PCF805 14 6 OAZ207 9 6 0C82 5 IZMTo 7 40669 29 B8l 9 Z Range il 9006 2 6 EABCSO 6 6 E d VeGT 6 30LI 17 EFl84 T7 PCF808 13 OAZ208 to OC82DM 3 IZMT10 6 9 AC126 4 6 B82 9 8 Zener diodes EX e soris iJ lom Tubes rari 10 EFL200 15 6 PCF808 14 6 OAZ213 6 6 0C83 4 e lIZT 13 6 AC127 4 6 BU100 36 3 6 ea Paa HE EL34 10 8 PCH200 14 0AZ223 to OC83B 8 IZT10 12 9 AC128 6j BYZ13 5 Z2A range EBC33 BL pL 11 6 PCL81 9 6 OAZ22 5 10 OC84 _H 2N1306 G B ACI7S 7 6 BYZIG 15 7 6 ea EBOH 198 ga 106 PCLa2 T 6 OCI8 18 OC122 2N1307 6 6 ACY98 _4 CRS1 10 bj Z3B range EBES0 ee EL84 49 PEL8S3 18 0092 8 6 0C139 2N3053 6 61 AD149 11 CR81 20 9 6 5 ea EBES Telers v3 rcnu se ocn Vejoctao 3 2N30 4 18 6 ADIGL 7j CRSU S0 107 ZL range EbFS3 Tikpss S PoLea 8 6 0626 S OCITO S 2N3006 18 ADIS2 Ti CRSl 8S 11 6 5 ea iELS0 6 PCLa6 8 6 OCo8 12 6 OCI71 6 F100 12 6 AF117 4 9 CR81 40 12 8 ZB range 6X50 5 30P12 16 VCR97 32 6 6X5GT 5 6 30P19 14 VCR517 50 6Y6G 11 30PLI 18
121. 40 7 6 IRS 7i 30FL1 15 EZ4l 9 185 5 30FL12 18 6 EZ80 5 6 lT4 4 6 soFL14 15 6 EZ81 5 6 1U4 8 soL15 17 GZ32 9 6 IUS 9 6 30L17 17 GZ34 11 2D21 6 6 30P12 16 KTeo 27 6 3Q4 8 30P19 15 KT88 33 6 384 7i 30PL1 18 6 MU14 8 avd 8 30PL13 18 PABC80 8 5R4 ll 30PL1417 PC86 11 6 5U4 8 35L6 9 6 PCas 18 6v4 8 35W4 5j PC97 8 6 5Y 3 6 3524 5 PC900 9 6 Z4G T7 6 357z5 7 PCCS4 7 6 30L2 15 50B5 9 PCC85 8 6AC7 4 50C5 7i POC88 12 6AG7 7 6 Bo 9 PCCR9 10 6 6AK5 0 85A29 7 8 PCC189 n 6AK6 11 6 807 9 6 PCF80 6 6 6AL5 3 8 1625 6 PCF82 6 9 6AMG 4 8 5763 13 PCF84 9 6AQ5 6 6 6146 30 PCF86 11 6A86 6 AZ31 10 PCF800 6AT6 5 cY31 7 15 6AU6 B DAF91 65 6 PCF80110 6AV6 68 6 DAF96 7 9 PCF80210 6BA6 4 6 pro 4 6 PCF805 15 6BEG b5 DFo6 7 8 PCF806 13 6BH6 8 8 DK91 7 PCF808 15 6 6HJ6 8 6 DKo2 9 PCL82 7 9 6BQ7A 7 6 pK96 8 PCL83 13 6BR7 17 DL 7 PCL84 8 9 6BR8 13 Died 8 PCL85 9 6 6Bw6 16 DL96 7 6 PCL86 9 6 8BW7 13 6 DM70 6 6 PFL20011 6BZ6 6 8 Dya6 sie PL36 11 6C4 8 DY87 7 PL81 9 6 6Cb6 23 EssCC 12 6 PL82 9 6CL6 10 E180F 16 PL83 8 6CW4 12 6 EABCS0 6 6 PL84 7j 6Fl 12 6 KAF42 10 PL500 15 6F6G 5 EBL 8 3 PL504 16 6F13 7 EBC41 10 6 PY32 11
122. 4ET TELEPHONE 01 723 B211 Shop open 9 6 Monday Saturday Thurs 1pm arrangement provides d c feedback for stability and gives a high input impedance As the circuit has a high gain extending far into the radio frequencies some top cut must be introduced to ensure stability for audio use This can be done by connecting an external capacitor up to 1000pF between tags 10 and 11 The amplified signal across R6 is fed by emitter follower Tr6 to the complementary p n p n p n amplifier Tr7 Tr8 This provides a low impedance emitter follower output on pin 13 The basic wiring needed to operate the ic as a stereo preamp is shown in Fig 2 Each channel has a feedback network wired from the output to the invert input to give an overall frequency response Feedback Inputs Left Feedback network Fig 2 Basic wiring of MC1303P for stereo preamp use appropriate to the signal source The device needs a centre tapped power supply of between 9 0 9V and 15 0 15V d c and the current drawn is only 22mA approx The centre tap is needed to provide a bias connection for the input stages and is a suitable earth point for the input and output cable screens PREAMP WITH LEVEL RESPONSE The circuit in Fig 3 is suitable for low level signal sources which do not require equalisation It gives a signal gain of 40 dB ie 100 with a response of 10Hz 50kHz 3dB Since the lower end of R2 is returned to earth at a f b
123. 55 PCC805 0 85 PCC806 0 80 PCF80 0 80 PCF82 0 35 PCF84 0 50 PCF86 0 60 PCF87 0 85 PCF801 0 50 PCF802 0 50 PCF805 0 75 PCF806 0 70 PCF808 0 75 PCH2000 70 PCL81 0 50 PCL82 0 85 PCL83 0 85 PCL84 0 45 PCL85 0 40 PCL86 0 45 PCL88 0 90 PCL800 0 98 PCL801 0 70 PD500 1 50 PF86 0 60 PF818 0 85 PFL2000 70 PL33 0 35 PL36 0 55 PL81 0 50 PL82 0 45 PL83 0 45 PL84 0 40 PL302 0 80 PL504 0 80 PL508 0 90 PL801 PM84 PY31 PY33 PY80 PY8L PY82 PY83 PY88 PY500 PYS800 PY801 PZ30 QQV 6 2 15 QQV03 10 1 25 QQV03 204 5 25 U191 U201 U281 U282 U301 U403 U404 U801 DELI Soon First Quality Fully Guaranteed eercsess on 5 to t Qo Go Go eoe ooo o0 DDOD za ie co ia o0 26 soesscoss BRAND to Go Goto ga to 2 m to ie co 0 35 UAF41 0 50 UAF42 0 55 UBC41 0 50 UBC81 0 40 UBF80 0 40 UBFS9 0 35 UBLI UBL21 UC92 UCCB8b UCF80 UCH21 UCH42 UCH43 UCHS81 UCL82 UCL82 UCL83 UF4l UF42 UF43 UFS80 UF85 UF89 UL41 UL84 UM84 UYIN UYil UY41 UY82 UY85 W729 Z803U TWO NEW MULTIMETERS FROM RUSSIA oOooocpoeoooooo iO O 0 a 6 SAH Suypereeyeenuaye I I I II ELECTRONIC VALVES 26Z6GT 0 65 30A5 0 45 30AE3 0 40 30C1 0 80 30C15 0 80 30C17 0 85 30018 0 75 30F5 0 85 30FL1 0 70 30FL12 0 93 30FL14 0 75 30L1 0 40 30L15 0 85 30L17 0 80 30P12 0 80 30P19 0 80 30PLI 0 70 30PL13 0 98 30PL14 0 90 3543 0 55 35A5 0 75 35B5 0 85 35C5 0 40 35D5 0 70 35L6GT0 50 35W4 0 80 3023 0 80
124. 6 Please send all orders direct to our warehouse and despatch department BPOS 7495N 4 Bit Up Down Shift Register 22 6 20 17 8 BI PAK SEMICONDUCTORS BP96 7496N 5 Bitshlftreglter 94 21 18 P O BOX 6 WARE HERTS Postage and packing add 1 Overseas add extra for Airmail Minimum order Data is available for the above Series of Integrated circuits in booklet form price 2 6 10j Cash with order please 687 MW LW TRANSISTOR RADIO Complete set of parts for this MW LW Transistor Radio Originally sold by world famous company as a set for more than 17 Coverage 192 555m 1070 1870m 44 loudspeaker Transistors 3 x AF117 OC81 D 9 OCS1 Also works off car aerial Full instruction book 2 6 free with parts State preference red blue or tan and give alterna tive Requires PP7 battery price 4 6 extra All parts 6 17 6 4 6 post or 10 10 0 fully built 4 6 post A few left of Super Six Kit see previous issues at 4 5 0 4 6 post 9 volt 6 transistor superhet using 3HF AAI7 in RF and 1F stages powered by a two stage AF amplifier using OC81D x OC8I Ontput approx 500MW STEREO AMPLIFIER type HV 2 x 3 Watts Fully built On off sep vol and tone each channel 12 br x 4 x 6in high EZ80 2 x ECL86 for 3 ohm speakers double wound main trans fixing flange and base plate suitable for crystal cart tuner etc 6 10 0 8 p amp p 200 250V A G Superio
125. 7 9 1112 6 UNIT 5 Speaker Kit 2310 0 1819 6 PHILIPS RH580 26 0 o 1919 6 GARRARD SL 65B 09 6 5 1419 6 BIGNLEB SAN 25 0 62 3 1 eas 16 GARRARD SL 758 35 12 4 2819 6 CHASSIS SPEAKERS PIONEER SA700 98 0 0 119 6 GARRARD SL95B 45 9 1 38 19 6 GOODMANS Axiette 8 19 6 PIONEER SA900 134 2 0 919 6 ARRARD 401 3114 2 2610 GOODMANS Twinaxiettes 8 8 8 PIONEER Reverberatlon 45 911 3519 6 GARRARD SL 72B 30 2 0 2419 6 M GOODMANSTwinaxiomi0 9 8 5 QUAD orenean Gua 0 o 38 19 e GARRARD 2500 with GKS GOODMANS Axiom 10 816 8 H QUAD 303 Main Amplifier 55 0 0 4819 6 Cartridge 15 15 O 11 19 6 GOODMANS Axiom 201 13 9 0 ROSES an pmblifer Eso 1a 0 gas te 6 GARRARD base and cover to fit SP25 S159 GOODMANS Axiom 301 19 5 0 H Ravensbourne cased 64 0 0 4919 6 SL65B and 3500 Special price 319 6 GOODMANS Audlom 51 12 3 0 0 Rave et s WD CLE VU GOLDRING GL69 Mk Il 26 12 6 2110 0 GOODMANS Audiom 61 17 12 0 i e anaoa ae GT 49 0 0 3 19 6 GOLDRING GL69P Mk li 35 2 10 2719 6 GOODMANS Audiom 81 2913 0 H TELETON 150 replaces 203E 29 0 0 19 19 6 GOLDRING GL 75 36 8 2 2919 GOODMANS Audiom 91 3312 0 TELETON GA101 30w RMS 33 15 0 2519 6 COLORING GL75P 46 18 8 3919 GOODMANS Axiom 80 26 14 6 SINCLAIR 2000 30 9 0 2310 9 GOLDRING Covers for 69P GOODMANS Audiom 91 100 34
126. 9 6 KEF Celeste 29 0 0 0 SANYO State T 126 0 0 WRARFEDA E 1001 T 13 5 i2 Sinne KEE Concord Ns a o i MR 590 tereo Tape Deck 5 All above Tuner Amplifiers are complete wit x concerto Hise v stereo decoder except where starred KEF Cresta 2 34 TELETON FXB 5100 Stereo ae LEAK Sandwich 4510 0 6 TOSHIBA GT601V 45 3 0 TURNTABLES LEAK Mini Sandwich 2915 0 6 PICKUP ARMS ARENA SP25 with base cover 22 1 0 1719 6 LEAK 300 2110 0 6 B S R McDONALD MP60 15 0 0 1019 6 LEAK 200 93 10 0 6 GOLDRING Lenco L75 12 6 6 1010 0 BRS McDONALD 610 1819 6 1319 6 LEAK 600 4 amp 5 00 6 GOLDRING Lenco L69 959 7 00 DUAL 1219 transcription 60 8 0 50 19 6 LOWTHER Acousfa SME 3009 with S2shell 31 6 3 25 19 6 DUAL 1209 transcription 42 12 4 35 19 6 with PM6 E 4510 0 6 SME 3012 with S2 shell 33 7 3 28 19 6 COMET Hi Fi DISCOUNT WA Reservoir Road Clough Road Hull HU6 7QD Tel 407906 amp 407877 Customers are welcome to call personally also at 68a Armley Rd Artist St Leeds LS12 2EF Tel 32055 une Ample Car Parking facilities Comet guarantee that all prices quoted are genuine All items offered available at these prices at the time this issue closed for press Comprehensive Add 9j for post and packing on all orders cartridges 4 Make cheques Money Orders payable to COMET Hi Fi Catalogue available 5 If Securicor Delivery Requi
127. A Rated 20 watts Voice coils available 3 or 8 or 15 ohms Major Module 30 17 000 cps with tweeter crossover baffle fl l 10 0 19 x 12 in and instructions Latest Catalogue 1 with enclosure plan Bensham Manor Road Passage Thornton Heath Surrey Telephone 01 684 1665 multi drawer storage units NEW HANDY TIDY I N T E R L O C K I N G Newest neatest system ever devised for storing small parts and components resistors capacitors diodes transistors etc Rigid plastic units interlock together in vertical and horizontal combinations Transparent plastic drawers have label slots removable space dividers Build up any size aem cabinet for wall bench or table top BUY AT TRADE PRICES SINGLE UNITS Sins x 2jins x 2dins Usually 2 6 each Our Price 24 dozen DOUBLE UNITS Sins x 44ins x 2jins Usually 4 6 each Our Price 40j dozen PLUS QUANTITY DISCOUNTSt Orders 5 and over Deduct I in the Orders 10 and over Deduct 1 6 in the Orders 20 and over Deduct 2 in the Packing Postage Carriage Add 6 to all orders under 3 Orders 3 and over Packing postagelcarriage free Quotations for Larger Quantities Dpt PW10 31 ALBERT RD HENDON LONDON NW4 A place for everything Everything in its place TECHNICAL TRAINING in radio tele vision and electronics Whether you are a newcomer to radio and elec tronics or are engaged in the industry and wish t
128. AIL 1 0 0 1 i 4 M Australia New Zealand S Africa Canada and U S A e PHOTOELECTRIC BURGLAR ALARM INVISIBLE BEAM TYPE Also Essential Data Circuits if and Plans for Building A M o ui IBN 10 Advanced Designs INVISIBLE BEAM OPTICAL KIT Everything needed except plywood for building 1 Invisible Beam Projector and 1 Photocell Receiver as illustrated Suitable for all Photoelectric Burglar Alarms Counters Door Openers etc CONTENT S 2 lenses 2 mirrors 2 45 degree wooden blocks Infa red filter projector lamp holder building plans etc Price 19 6 Postage and Pack 1 6 U K Commonwealth Surface Mail 2 Air Mail 8 LONG RANGE INVISIBLE BEAM OPTICAL KIT CONTENTS As above Twice the range of standard kit Larger Lenses Filter etc Price 29 6 Postage and Pack 1 6 U K Commonwealth Surface Mail 2 6 Air Mail 10 JUNIOR PHOTOELECTRIC KIT Versatile Invisible beam Relay less Steady light Photo Switch Burglar Alarm Door Opener Counter etc for the Experimenter CONTENTS Infra Red Sensitive Phototransistor 3 Transistors Chassis Plastic Case Resistors Screws etc Full Size Plans Instructions Data Sheet 10 Advanced Photo electric Designs Price 19 6 Postage and Pack 1 6 U K Commonwealth 2 Air Mail 4 JUNIOR OPTICAL KIT CONTENTS 2 Lenses Infra red Filter Lampholder Bracket Plans etc Everything except plywood to build 1 m
129. B would be ill advised to embark on a similar venture next year without a major re think What is needed is an all embracing show revolving around the hobbyist possibly run by a consortium of interests covering not only purely amateur radio but taking in all types of associated interests be it hi fi tape recording electronics and the like And give it a title that means something and sounds more attractive than some thing from 1984 Then we might find companies more willing to take stands and the lost visitors starting to flock back again W N STEVENS Editor JANUARY ISSUE WILL BE PUBLISHED ON DECEMBER 4 PRACTICAL WIRELESS VOL 46 NO 8 Issue 766 DECEMBER 1970 NEWS AND COMMENT Leader 623 News News News 624 On the Short Waves by Malcolm Connah and David Gibson G3JDG 631 Letters to the Editor 633 MW Column by Charles Molloy 661 CQ CQ CQ CQ 669 Practically Wireless by Henry 670 CONSTRUCTIONAL Amateur Bands Communications Receiver Part 1 by W Cameron 626 C Stereo Equalisers amp Mixers by Caleb Bradley B Sc 634 Audio Visual Continuity Tester by M A Sparks 642 1 C of the Month Motorola MC1596G Modulator Demodulator by L A J Ireland 646 A Sensitive Telephone Amplifier by C R Bradley 648 P W 25 25 Stereo Amplifier Part 2 by F C Judd 652 Take 20 Megaphone by Julian Anderson 678 OTHER FEATURES Going Multiband by Eric Dowdeswe
130. BROTHERS ES have acquired the manufacturing rights of D WAVEMASTER B VARIABLE CAPACITORS Rare Wavemaster variable capacitors have brass vanes and a single ceramic end plate All have 248 spindles extended both ends for ganging by means of our Universal Couplings All are designed for S W working and for one hole fixing 6mm spindles to order if required Various capacitances Largest vane packs 300 pF 017 air gap 50 pF 0 64 air gap TYPE 92 SW Tuning Law YPE amp LC LAW Type 87 S L C Law Plain bearings 2 fixing bush Front area 142 w x 12 h Type 95 S L C Law Ball bearings 4 dia fixing bush Type 92 Modified S L C Law S W Tuning Plain bearings dia Front area 11 w x fixing bush Front 11 h area 11 w x 1 h JACKSON BROTHERS London LTD Kingsway Waddon Croydon CR9 4DG Phone 01 688 2754 5 U S Office M Swedgal 258 Broadway New York N Y 10007 PHOTOELECTRIC KIT CONTENTS 2 P C Chassis Boards Chemicals Etching Manual Infra Red Photo transistor Latching Relay 2 Transistors 3 Diodes Resistors Gain Control Terminal Block Elegant Case Screws etc In fact everything you need to build a Steady Light Photo Switch Counter Burglar Alarm etc Project No 1 which can be modified for modulated light operation TX PHOTOELECTRIC KIT rn 39 6 t a e ria 8 Postage and Pack 2 6 UK Commonwealth SURFACE MAIL 3 6 AIR M
131. C8 10 8 PY81 6 3 VP4B 15 6 6F25 12 6 807 9 ECH83 8 8 PC88 10 38 PY82 5 8 Wils T7 655Q 4 9 6063 12 6 ECH84 7 6 PC96 8 6 PY83 5 9 Z77 4 6 6K7G 2 6 AC VP215 6 ECL80 7 PC97 8 PY88 0 0 Transistors 6K8G 8 6 AZ31 9 6 ECL82 6 9 PC900 7 6 PYSO00 7 6 AC107 3 6 6V6G 3 6 B349 13 ECL86 8 PCC84 6 6 PYsSUl 7 8 AC127 2 8 6V6GT 6 6 B729 12 6 EF37A 6 8 PCC8S 8 R19 6 6 AD140 7 6 6x4 4jb CCH35 13 6 EF39 4 9 PCC88 9j R20 12 AFMa 3j X5GT 65 9 CL33 18 6 EF41 11 9 POC89 9 0 RU2100A AFI6 3j 10Fi8 7j CY31 6 9 EF80 4 6 PCC189 9 9 12 6 AF117 4j 10P13 12 DAC33 7 3 EF85 8 3 PCC805 13 U25 13 AFIZ5 3 8 12AH8 45j DAF91 4 3 EF86 8 3 PCF80 6 6 U26 12 AF127 8 6 12AT7 3 9 DAF96 7 3 EF89 5 3 PCF82 6 6 1147 18 6 OC26 5j 12AU6 4 9 DF33 7 9 EF92 2 0 PCF80 9 6 1149 12 OCa4 2 6 12AU7 4 9 DF91 2 9 EF183 5 9 PCF80013 8 U78 4 g OC4 D 9 6 12AX7 4 9 DF96 7 3 EF184 6 6 PCF801 6 9 U191 12 8 OC71 2 6 12K8GT 7 3 DH77 4 0 EH90 8 8 PCF802 9 U193 8 6 OC 2 6 19BG6G17 6 DK32 7 6 EL33 9 9 PCF80513 8 U201 14 6 OC76 92 8 20F2 19 6 DK91 5 B EL34 6 PCF806 11 2 U301 10 6 OC81 2 6 20P3 11 9 DK92 8 6 141 11 PCF80814 U329 14 8 OC81D 2 6 20P4 18 6 DK96 7 3 EL84 4 0 PCLS2 7 8 U80 19 8 OCBz 9 6 25L6QT 5 DL35 5 EL90 5 3 PCL83 12 UABCRO 8 8 OCB2D 2 8 25U4GT11 6 DL92 5 9 EL500 12 6 PCL84 7 6 UAF4 10 3
132. COUNTS FOR QUANTITIES POWER RHEOSTATS 5 A High quality ceramic construction Windings embedded in vitreous enamel available Heavy duty brush wiper Continuous rating Wide range available ex atock Bingie hole fixing jin dia shafts Bulk quautities 25 WATT 10 25 50 100 250 500 1000 1500 2500 or 5000 ohms 14 6 P amp P 1 6 50 WATT 10 25 60 100 250 500 1000 2500 or 5000 ohms 21 P amp P 1 6 100 WATT 1 5 10 25 50 100 260 500 1000 or 2500 ohms 27 6 P amp P 1 6 FTC 401 TRANSISTOR TESTER Full capabilities for mea suring A B and ICO NPN or PNP Equally adaptable for checking diodes Supplied come plete with instructions battery and leads 6 19 6 P amp P 3 MARCONI TF142E DISTORTION FACTOR METERS Excellent condition Fully tested 890 Carr 15 TRANSISTORISED L C R A C MEASURING BRIDGE A new portable bridge offering ex cellent range and accuracy at low cost Ranges R tQ I1 meg 6 Ranges 1 L u H lii HENRYS 6 Ran ges 2 C 10p 1ll0mFd 6 Ranges 2 TURNS RATIO 1 1 1000 1 11100 6 Ranges 1 Bridge voltage at 1 000 eps Operated from 9 volts 100A Meter indication Attractive 2 tone metal ease Size 7 x 5 x 2in 20 P amp P 5 COSSOR 1049 DOUBLE BEAM OSCILLOSCOPES D C coupled Band width 1Ke s Perfect order 225 Carr 30 TE 20D RF SIGNAL GENERATOR Accurate wide range sig nal generator covering 120 Xc s b00 Me
133. D AIR PRICE 35 PRICE DE LUXE STEREO HEADPHONES With soft rubber earpieces Imped ance 8 16 obms Frequency re sponse 23 13 000 cps With lead and stereo plug 59 6 z SOLDERING GUN Comfortable grip with tripger coatrol U ahaped 8j bit to miui mise wear Light beam ia automatically directed on to end of bit when ON OFF trigger is in use 230 260 volts 85 watt element 49 6 P amp P 3 6 British Made Solderless breadboard panels for fast re liable component connections Single DeCs One 8 DeC with Control Panel Jig and Accessories for solderless connections to controls etc with booklet Projects on DeC giving construction details for a variety of circuits 29 6 P amp P 2 6 4 DeC KIT Four 8 DeCs with two Control Panels Jigs and Accessories and the book let Projecta on S DeC all contained In a strong attractive plastic case Ideal for the professional user 25 17 86 P amp P 3 6 T DeC KIT 42 10 0 P amp P 3 6 a P PPP Hi FI TURNTABLES 2025 T C with stereo cartridge 28 19 6 3000 with Sonotone 9TAHCD stereo cartridge 210 19 6 SP25 Mk II 10 19 6 SL65B Base and cover for AP75 BL72B SL75B BL9SB 401 Deck Base Cover 17 6 SPECIAL OFFERS SP25 Mk II with base 14 10 0 P amp P 15 SP25 Mk II with Sonotone 9TAHCD cartridge and base 1515 0 P amp P 15 Sonotone 9TAHCD cart ridge 2 15 0 P amp P 1 6 LiN
134. D AiR AUDIO TELETON SAQ203 TRANSISTOR SAVE ie STEREO AMPLIFIER d H M OFF AKAI 1 H ie m M pr Superb quality hi fi 10 watts per 3 zt P i Fi S channel music power Inputs for 3l i e T ih Gram Magnetic and Crystal HIDE Tuner and Auxiliary Tape Record STEREO H tee i E y utput Controle Volume Balance EBD cid f 1 i p Bass Treble Attractive oiled TAPE RECORDERS d H HELT walnut cabinet and brushed alu 1 3 Ht at minium front panel List Price 28 7 0 Only tak 1 D AIR PRICE undis S uad ready for use Li N D IR PEN He ce ns Lind Air LA20 Amplifier 223 2 0 P R C E E Garrard 5 200 Changer with Pob AO Sonotone Cartridge 11 7 6 Pair of Lind Air General 39 g Purpose Speakers 219 0 0 2 ns Recommended Retail Price Carr amp Ins 36 SPECIAL LIND AIR PURCHASE FANTASTIC SANSUI 200 AM FM MULTIPLEX STEREO TUNER AMPLIFIER ae Solid atate 17 watts music power Fully SCOOP PURCHASE gt turnable over Medium wave and VHF FAMOUS SANYO COLORANO FM Stereo Inputa for gram and tape ete Host of outstanding features details on TRENT TOR AER RADIO request Rec Retail Price 89 19 10 LIND AIR PRICE 99 YOURS 91 gns Fer LIND AIR PRICE 78 12 0 P amp P 10 Carr amp Ins 35 FORCE Batteries 3 4 extra us rr amp Ing 35 our atteries extra A complete stereo tape recorder 2 speeds E Elegantly styled quality 10 transistor radio 3 amp 7 ipa and offering full stere
135. DECKS AND TAPE PICTURE VEE LE PRIM avensbroo ds 0 ALi MAKES STOCKED AKAI X 360 339 0 0 ROGERS RavensbrooK gsi 3 AES CARTRIDGES a oiscount prices AKAI X 3600 deck 290 0 0 SINCLAIR 2000 2614 6 19 4 6 A y ruo ERR TELETON GT101 4710 0 33 19 6 DELIVERY BY SECURICOR AKAI 1800SD e 109 0 0 TELETON 201X FM 36 0 0 29 19 6 AKAI 4000 124 18 0 TRUVOXFM2001C gt 60 1110 3919 6 WITHIN 72 HOURS AKAI 4000 D deck 89 19 1 All above tuners are complete with MPX stereo ALL IN STOCK items delivered by SECURI ALBA R22 Battery Mains 50 5 0 decoder except where starred COR within 72 hrs Add 20 only for Securicor BUSH TP 60 Cassette 29 8 0 TUNER AMPLIFIERS delivery All goods fully insured against loss BUSH TP 70 Cassette ARENA 2400 90 6 0 119 6 or damage whilst in transit Battery Mains hz 2019 0 ARENA 2600 Stereo AM FM zn 6 0 94 0 0 SPEAKERS FERGUSON 041 at k 28 4 A ARENA 2700 Stereo m 00 85 0 0 FERGUSON 3248 RICH ARENA 2700 Stereo gt M 9 0 59 19 ARENAHT27 18 18 0 a f FERGUSONGSMS Ne Y E 0 0 ARENA TOO 303 9 0 258 0 0 ARENA HT 28 17 17 0 6 FERGU N 3249 4 track 64 6 0 ARMSTRONG S25 9117 9 76 19 6 ARENAHT21 1010 0 0 T SON 3244 Stereo ARMSTRONG 526 104 14 3 86 19 6 ARENA HT 7 o 19 19 0 0 GRUNDIG MEET 2 1 zd ARMSTRONG M8 decoder 010 0 719 6 ARENA HT 10 22 1 0 ARONET C200 assette 37 19
136. E M I Speakers Total cost if purchased separ VERITAS V 149 MIXER NETIC STEREO separate inputs Size 6 x 3 x Zin suitable fur crystal micro CARTRIDGE COM pbone low impedance iniero PLETE IN TEAK phone with transformer radio tape etc Max input 1 by Max output 2 5v Gain phonoplugs Attractive teak MANUFACTURED IN U S A FROM EXTRA STRONG the most permanent base Highly resistant to break ON W 1 E or stereo amplifier Garrard 2025 T C auto ted in teak finish plinth with perspex cover PREMIER STEREO SYSTEM TWO As system ONE above but with Garrard BP25 Rice 45 Gns Carr 35 TWO STATION TRANSISTOR INTERCOMS Complete with battery and 50ft connecting wire Compact size two way call system Ideal for home office factory etc 65 5 7 E M lI 13 X8in HI FI SPEAKERS Fitted two 2 in tweeters and crossover network Impedance or 15 ohm Handling capa city 10W Brand new T9 6 P amp P 7 6 erful amplifier designed for stereo hib ono slide witch Stereo headphone P amp P 10 22 Gns WELLER EXPERT SOLDER GUN Saves time and simplifies soldering in the home and service dept Two position trigger gives instant dual heat 100 140 watt IRP amp P EE B20 E oO ne G B ios ie E Markaman Soldering lron Lightweight Po oe 6 19 6 x pencil bit Ideal for regular bench use E ne 5 10
137. E NN RES NS NN ENDO UN PoST PE SEND ME FREE DETAILS OF YOUA RANGE THIS ATS i ie CTUM iy S ett o SOUTHGATE Dep P1170 LONDON N 14 TELEPHDNE 886 3733 9666 mE NE EE NR ERE NM NE ER ND SD EB RR NEW BI PAK UNTESTED V C AMPLIFIER B PAK SEMICONDUCTORS Mc de Satisfaction GUARANTEED in Every Pak or money back Identic El encapsulation Pak No and pin configuration to the following SL409 3 NEW LOW PRICED TESTED S C R s SIL RECTS TESTED El 120 Glass Nuberuin General Purpose Germanium Diodes 10j Y 3103 E IA 3A 74A 16A 30A ICtO and 1C403 Each PIV 750m A 3A v2 60 N xed Germani n Transistors AF BE 10 circuit incorporates a pre TO 5 TO 66 TO 48 TO 48 50 2 9 43 ot yo amp and cl A B case case case case 100 3 3 4 6 l5 1 4a Power amp stage capable PIY each each each each PIV each 200 4i 4 9 20j 1lo or delivering up to 3 watts 50 Sj 9 6 10 6 20 300 416 616 22 10 RMS Fully tested and 100 6 6 10 6 12 6 50 23 400 5 6 7 6 25j 30 j guaranteed Supplied 200 7 6 11 6 15 100 28 500 3 6 8 6 10j complete with circuit F 400 9 6 13 6 18 6 200 32 600 6 9 9i 3 600 11 6 15 6 25 400 35 800 7 6 lij 10 BPl0j0 OUR LOWEST 800 I4 18 30 800 80 1000 5 9 3 12 6 7 10 PRICE 30 each PRINTED CIRCUITS EXCCOMPUTER 1200_ 6 6 11 6 15 Cii xo PNP Silicon Planar Transistors TO
138. ERVICE NEW TESTED GUARANTEED VALVES lA7GT 7 8 30C1 6 6 DL94 6 9 EM34 14 6 PCLSo 9 UBC4L 10 6 1H5GT 7 8 30C15 18 DL96 7 8 EM80 8 3 l UL86 8 3 UBF80 5 9 1N5GT 7 9 30C17 16 DY86 5 8 EM81 8 3 PCL88 14 6 UBFB9 6 9 1R5 5 9 30C18 13 6 DY87 b 9 EMB4 6 9 PCLS00 15 8 UCC84 7j 155 4 3 30F6 15 9 EABC80 6 6 EM87 7 6 PENA4 8 6 UCC8G 7 3 1T4 2 9 30FLl 12 9 EAF42 10 EY61 7 3 PEN36C14 UCF80 7 3 384 5 9 30FLi2 14 6 EB91 2 3 EY86 6 6 PFL20011 9 UCH42 19 8 v4 6 9 30FL1414 EBC33 8 EZ40 8 PL36 9 8 UCH81 6 6 b5Y3GT 6 30L1 6 8 EBC41 10 6 EZ41 84 PL8 9 8 UCLB2 7j 5240 7 6 30LI5 18 EBF80 6 9 EZ80 4 6 PL8IA 10 8 UCL83 ll 6 30L2 11 9 30L17 14 8 EBF89 6 3 EZ81 4 8 PL82 6 UFa1 10 6 GALS 2 3 30P4 13 ECC81 8 9 GZ39 8 9 PL83 6 8 UFAG 6 9 6AM6 2 9 30P12 18 9 ECC82 4 9 GZ34 9 9 PL84 6 6 UF89 6 9 4Q5 5 3 30P19 18 ECC83 7 KT41 15 6 PL500 13 UL4l 12 GAT 4 6 30PL1 12 9 ECC85 5 98 KT61 9 9 PL504 18 6 UL44 20 6BAG 4 6 30PL13 14 6 ECC80412 KT66 16 9 PL 08 23 6 UL84 7 6BE6 4 9 30PLI414 ECF80 6 LN329 14 6 PM84 7 6 UM80 Bj 6BJ6 8 8 35L6GT 8 9 ECF82 6 N78 17 6 PX2b 23 6 UM84 4 6 6CD6G 28 35W4 4 6 ECH35 6 P6 10 PY32 10j UY4i1 7 6 6F14 9 35Z4GT 5 ECH42 12 9 PABCSO 7 PY33 10 UY8 5 9 6F23 13 9 150BE 13 6 ECH81 5 9 P
139. EST RONETTE T O STEREO COMP L A top quality record player amplifier employing heavy CARTRIDGE for EP LP Stereo 78 82 0 P amp P 2 duty double wound mains transformer ECC83 ELS4 LATEST RONETTE T O MONO COMPATIBLE CART and rectifier Separate Bass Treble and Volume controls RIDGE for playing EP LP 78 mono or stereo records Complete with output transformer matched for 3 ohm on mono equipment Only 80 P amp P 2 speaker Size 7in wide x 3in deep x Gin high Ready built and tested PRICE 75 P amp P 6 HIGH GAIN 4 TRANSISTOR ALSO AVAILABLE mounted on board with output PRINTED a transformer and speaker ready to fit into cabinet below AL R KIT PRICE 97 6 P amp P 7 6 Type T DELUXE QUALITY PORTABLE R P CABINET MK II Peak output Uncut motor board size 144 x 12in clearance 2in below in excess of 54in above Will take above amplifier and any B 8 R or 14 watts All GARRARD changer or Single Player except AT60 and standara SP25 Size 18 x 15 x 8in PRICE 79 6 P amp P 9 6 British com 10 14 WATT HI FI Bait ae AMPLIFIER KIT or easy construction A really first class Hi Fi Stereo Amplifier Kit Uses 14 transistors including Silicon Transistors in the first five stages on each channel resulting in even lower noise level with improved sensitivity Integrated pre amp with Bass Treble and Volume controls Suitable for use with Ceramic or Crystal cartridges Output stage for any spe
140. EW RANGE U H F TV AERIALS All U H F aerials now fined with tilting bracket and 4 element grid reflectors Loft Mounting Arrays 7 element 45 11 element 52 6 14 element 60 18 element 70 Wall Mounting with Cranked Arm 7 element 65 11 element 75 14 clement 82 6 18 element 90 Chimney Mounting Arrays complete 7 element 80 1 element 87 6 14 element 95 18 element 105 Complete assembly instructions with cvery aerial Low Loss co axial cable 1 8 yd King Teleboosters l abgear U H F Boosters from 75 Belling Lee Concord al Band V H F U H F mains operated pre amp 7 10 0 State clearly channel number required on all orders p p Aerials 8 Accessories 3 C W O or C O D BBC ITV FM AERIALS B B C Band 1 Loft 25 Wall S D 32 6 H array 60 I T V Band 3 5 element loft array 45 7 element 55 Wall mount ing 5 element 65 Com bined BBC ITV loft I 5 55 7 67 6 Wall mounting 1 5 77 6 Chimney mounting 1 5 90 Preamps from 75 Combined BBC1 ITV BBC2 Aerials 1 5 9 80 14 5 1490 1 7 14 100 Available loft only F M Radio Loft S D 19 6 H 38 6 3 element array 57 6 Standard co axial cable yd Coax plugs 1 8 Outlet boxes 6 Diplexer crossover boxes 17 6 p p Aerials 8 accessories 3 C W O or C O D min C O D charge 3 6 1 for fuliy illustrated Lists Callers welcomed open all day Saturday K V A ELECTRONIC
141. F127 0C36 AF178 0C42 AF186 OC44 AF239 0C45 AFZIL oc70 ABY26 OCT7i ASY27 0C72 ARYUR OC73 ABY29 OCTS ASY54 O0CT76 ASY74 OC78 ASY77 oc7sD ASY82 OCBL ASY86 OC81D BCI07 O0C83 BC108 OC139 BC109 OC140 BCI13 OCI4l1 BC118 O0C170 BC134 OCI71 BC147 O0C200 043 OA3 OB2 OB3 0c3 OD3 183GT IL4 IR4 IRS 184 185 1T4 IU4 IU5 Iv2 TX2B 2D21 3A4 3B 8 3BP1 8Q4 384 6ARS GARA GAYS 6A87G 6AT6 GAUG SAVE 0 GAWSA 0 55 6BAG 6BE6 6BF5 6BPF6 6BH6 0 6BJG 0 46 6BKT74 0 55 6BL7GTA 0 65 6Y6G 7Y4 9BW6 10C2 10Di 10D2 10F1 10F9 10F18 10L1 10LD11 0 60 10P13 0 55 10P14 1 10 12AB6 12AC6 12AD6 12AL5 12AQ5 12AT6 12AT7 12AU6 12AU7 12AV6 12AVT 12AX7 12AYT7 0 12B44 AQ 12BA6 0 35 12BA7 0 35 12BE6 0 85 12BH7 0 40 12BY7 0 56 12K5 0 55 12K 7070 85 12Q7G 0 30 1 98R7 0 35 i487 0 80 20D1 0 45 20L1 1 10 20P1 0 50 20P4 110 20P5 1 20 25C5 0 50 25L6GT 0 45 2524G 0 80 0 85 0 60 0 50 0 50 0 50 0 40 EF41 EF42 EF80 EF83 EF85 EF86 EFS9 EF91 EF92 EF95 EF97 EF183 EF184 EF800 EK90 EL34 EL36 EL41 EL42 EL81 EL83 EL84 EL85 EL86 EL90 EL95 EL360 EL808 EL821 EL822 ELL80 EM34 EM71 EM80 EMS1 EM84 EM87 EN91 EY51 EY80 EY81 EY83 EY86 EY87 EY88 E240 EZ41 EZ80 EZ81 GY501 GZ30 GZ31 GZ32 GZ33 HABC80 0 45 HK90 0 85 KT68 1 70 KT88 1 76 N78 1 15 PABC80 0 40 PC86 0 60 PC88 0 60 PC97 0 50 PC900 0 48 PCC84 0 40 PCC85 0 40 PCC88 0 55 POC89 0 50 PCC189 0
142. F127 OA74 1907 47 100 2 3 281122 6 8 Ar139 oA BYI27 4i 2N1303 AF178 gt o i ANIA BI AFISI O48 malara poooy BYZI3 P wale 2 2NI305 5 AFING ABO 25 4 T f t id TARE D 25 4 3 3 PUES BEAD salou LEE 198 36 raintortomorrow swor 2N1308 6 AFZI1 g el 2N1309 6 AFZ12 AD AF239 8 BCI07 8 9 C a a 2N1013 4 6 ASY26 02 p 2N2147 15 A8Y27 OA 210 Siemens VHF 2 6 ea R d d T l 2N2100 ASTER OA2LL 25 7 LT T or Mullard In a 10 an e evision EE 5 neues er 100 6 25 2 3 2N9646 ABYG AZ9 500 5 100 2 2N2904 ASZ3I 0A2229 1000 4j 500 1 9 t Th P b d C il npo t Y10 AZ d a e em ri e 0 e e o 33M 5 PEENE A EA irs e E 2N3011 vE ullar i BCIO 16 SILICON Diodes 25 17 3 f El t 283001 pelos p 1 6 100 14 9 0 1 ec ronics 2N3058 BCl09 100 x 1 3 500 13 6 2N3702 BC113 500 I I x i 2N3703 RELIG 0c28 ael The next full time 2 year College Diploma 2N1705 OCA eS m b SEM Course which gives a thorough fundamental 2N3709 190 1 45 aliia training for radio and television engineers ET 500 4 3 starts on 5th January 1971 2N3730 oc 3i t 2N3731 Ocas ia S Mullard E EHE 25 4 3 A ra The course includes theoretical and practical anang Mo HET 500 1 9 instruction on Colour Television receivers and 284058 8 Fer T 8 is designed to cover the syllabus of the new City 2N4061 am le fius 1 n 1 2N4286 QCIF lard s Mutlard and Guilds Radio Television and Electronics 2N 4288 g FONS
143. Germ B99 200 Mixed Capacitors Post and packing 2 6 I 0 al Experimenters Pak of Integrated circuits Data supplied Diodes AAY42 OA91 0A79 OASI iN914 0C73 OC81 ocsiD 0C139 0 C140 FREE RETURN OF THE UNBEATABLE P I PAK NOW E VALUE THAN Tull ot short lead semiconductors and electronic components approx 170 We guarantee at least 30 really high quality factory marked Transistors PNP and NPN and a host of diodes and rectifiers Mounted on printed circuit panels Identification chart supplied to give some information on the transistors PLEASE ASK FOR PAK P 1 ONLY PI 2 P amp P on this Pak 10 Packs of your own choice up to the value of 10 with orders over 4 640 B88 50 B60 10 7 Watt Zener Diodes Mixed voltages 10 12029 10 Sil Trans NPN PNP equivalent to 10 0C200 1 2N706A BSY9S5A etc BY126 7 type Silicon Rectifiers 1 amp plastic Up to 1 000 volts Approx Quantity counted by weight B98 10 XB112 and XB102 equiv to AC126 10 AC156 OC81 2 OC71 2 NK 71 etc H4 Mixed Resistors Post and packing 2 m 250 Approx Quantity counted by weight 10 H7 40 Wirewound Resistors Mixed Values Postage 1 6 10 x 250mW Zener Diodse DO 7 min Glass Type AV 40 Good 40 10 1970 Mullard Daca Books Data and Equiva lents on Semiconductors Valves and Tubes Price 4 each P amp P 6d H9 3 ocrni Light Sensitive Photo T
144. HANGERS SLIB ooa eo 25 0 0 2025TC with stereo cartridge 817 6 3000 complete with 9TAHC stereo cartridge 7 sos 919 6 T 15 10 0 SL95B 35 9 9 One of the famous Garrard Synchro SL75B n Lab Series Takes 8 L P s Four speed auto changer incorporating a SINGLE PLAYERS tubular pickup arm and adjustable AP 7 10 0 stylusforce Wiredfor Mono and Stereo 5 18 10 0 AP75 with ADIGK NOW AT LASKY S SPECIAL PRICE mag cart 21 10 0 401 Transcription Complete with SONOTONE 9TA Unit 20 0 0 STEREO CARTRIDGE 10 19 6 BASES AND COVERS FOR GARRARD UNITS nr Type WB1 and WB5 for models AT60 Mk Il 2025 TC 3000 SL65B SL55 1025 SP25 Mk Il Price WB1 3 16 6 WB5 5 12 6 Type WB4 for models SL72B SL75B SLO5B Price 5 12 6 Perspex covers SPC1 for WB1 3 14 1 SPC4 for WB4 and WB5 allows unit to be played with the cover in place Price 4 8 0 SCOOPMT 65 SPECIAL OFFER EXCLUSIVE HI FI STEREO TUNER AMP OFFER THE MT 65 CHASSIS Solid state AM FM multiplex tuner with FET front end 17 4 17 watts stereo amplifier by world famous manufacturer Frequency response 20 45KHz Inputs 2 3mV mag p u and 140mV tape play Tape record output Controls Left right volume bass treble loudness monitor Tuning meter and stereo beacon Stereo phone jack Machined stainless steel front panel Overall size 20x 34x 16in List Price 75 SPECIAL PRICE 66 0 0 3 DE LUXE COMPACT PACKAGE OFFER LASKY S
145. I AL OFFER DE LUXE STEREO AMPLIFIER ac mains p 200 240 v Using HI FI LOUDSPEAKER SYSTEMS heavy duty Beautifully made teak finish enclosure with most ted ains attractive Tygan Uynair front Size 164 high x 104 transform wide x 6 deep Fitted with E M I Ceramic Magnet er with full 13 x 8 bass unit two H F tweeter units and wave recti crossover Power handling 10 watts Available 3 or fication 15 ohms impedance giving ade Our popular Stereo 8 8 Mk II now OUR PRICE 8 8 0 carr 10 pem further improved incorporating high Also available in 8 ohms with EMI 13 x 8 bass with negli uid ready drilled printed circuit board speaker with parasitic tweeter 6 10 0 Carr 10 gible hum Valve line up 2 x ECL86 Triode Pentodes 1 x EZ80 as full wave rectifier Two dual potentionmeters are provided for bass and trebie control giving bass and treble boost and cut A dual volume control is used Balance of the left and right hand channels can be adjusted by means of a separate Balance control fitted at the rear of the chassis Input sensitivity is apprexi nately 300m v for full peak output of 4 watts per charnel 8 watts mono into 3 ohm speakers Full negative feedback in a carefully calculated circuit allows high volume levels to be used with negligible distortion Supplied complete with knobs chassis size ll w x 4 d Overall height including valves 5 Ready built and tested i PRICE 8 18
146. ITIVE 12 LOUDSPEAKER real 28 19 0 Retail Price Incorporating the Fane specially developed High Power Voice Coil HIGHER SENSITIVITY HIGHER ACOUSTIC OUTPUT HIGHER POWER HANDLING WIDER FREQUENCY RANGE Available in alternative models TYPE A General Purpose Flux Density 20 000 lines ower Handling continuous 100 Watts Frequency Response 30 16 000 Hz Voice Coil Impedance 8 or 155 Weight 18 Ib Voice Coil Diameter 2 in Cone Single with Cone Single with Plastifiex surround Plastifiex treated surround ALSO AVAILABLE CRESCENDO 15 Full Frequency Range 35 18 0 TYPE B Bass Guitar etc Flux Density 20 000 iines Power Handling 75 Watts continuous Frequency Response 40 10 000 Hz Voice Coil Impedance 8 or 1551 Weight 18 Ib Voice Coil Diameter 2 in Manufacturers enquiries to FANE ACOUSTICS LTD Hick Lane Batley Yorks Sole Distributors to wholesale and retail trades LINEAR PRODUCTS LTD Electron Works Armley Leeds 676 BAKER 12in MAJOR 9 The remarkable quality and performance of the Major makes possible truly brilliant and rich sound from a single loudspeaker t recreates the entire musical spectrum from 30 to 14 500 c p s The unit consists of the latest double cone woofer and tweeter cone together with a special Baker CERAMIC mag net assembly having a flux density of 14 000 gauss and a total flux of 145 000 Maxwells Bass resonance 40 c p s For Hi Fi or P
147. K ohms m Operation in terna batteries Attractive 2 tone case 7 x 6 x 2 Price 17 10 0 Carr 3 6 MULTIMETERS or EVERY purpose TECH PT 34 1 000 HONOR TE 10A 20k Q Volt 5 o O P V 0 10 50 250 6 25 50 250 500 2 500 v D C 500 1 000V A C and 10 50 100 600 1 000 v A C D C 0 1 100 500mA 0 50uA 2 5mA 250mA D C D C 0 100K 39 6 0 6K 6 meg ohm 20 to P amp P 2 6 22 dB 10 0 100 mfd 0 100 0 1 mid 69 6 P amp P 3j MODEL TE 300 30 000 O P V Mirror scale overload protection 0 6 3 15 60 300 1 200V D C 0 6 30 120 600 MODEL TE 200 20 000 O P V Mirror scale overload protec tion 0 5 25 125 1 000 V D C 0 10 50 250 1 000 V A C 0 50 1 opov A C O 30aA 6mA uA 950 mA 0 60K 6 megQ amp omA 300mA G00mA 0 8K 20 to 62 db 75 amp oX 800K 8 meg ohm 20 to P amp P 3 63 db 5 19 8 P amp P 3 MODEL TE 90 50 000 MODEL TE 70 30 000 O P V Mirror scale overload O P V 0 3 15 60 300 600 1 200v D C 0 6 30 190 600 1 200v A C 0 30mA 3 30 300mA 0 16K 160K 1 6M 16 Megh 5 10 0 P amp P 3 protection 0 3 12 60 300 600 1 200 v D C 0 6 30 120 300 1 200 v D C 03 6 60 600mA D C 16K 160K 1 6 16 MEGQ 20 to 63 db 7 10 0 P amp P 3 TME MODEL TW 20CB FEA TMK MODEL TW 50K 46 TURES RESETTABLE OVER LOAD BUTTON Bensitivit 20K Q Voit D C 5K
148. LLATOR No 9 Size 12in x 8iin x Yin Ideal for VHF work 20 80 Mc s Functions are AM CW Deviation up to 40 Ke s RF meter Measuring levels RF output 1 microvolt to 100 microvolts set Mod set carrier controls Good condition with accessories 230V AC 12V DC 20 0 0 plus 15 p p TF 144 G Signal Generators 85 Kc s to 25 Mc s Good condition and complete with accessories 22 0 0 plus 30 p p AERIALS New Condition Whip type 11tt 12 6 each Used condition 12ft 10 each All collapsible type Post and packing 3 6 Bases for the above 5 post and packing 2 6 PYE VANGUARD TRANS RECEIVER Boot mounted Low band app 20 watts 20 valve QQV03 20A QQV03 10 etc less crystals 12 volt input Not tested Used condition with speaker and mike 6 10 0 carr 30 As above less mike and speaker 25 each 30 carr New lengths 50ft Coaxal cable 70 ohms approx coax plugs each end price 20 each post and packing 2 6 Magnetic Transducers new price 7 8 post and packing 2j New Aerial Wire on boards 7 22 uncovered Length 75ft 8 post and packing 2 6 New small fuse boxes 250 volts 15 amps 17 6 each post and packing 3 Headphones ex Gov DLE No 5 high impedance New 17 6 3 6 p p Used condition 12 6 3 6 p p Meters moving coil ex equipment good condition Also 20 amp DC 40 amp DO and RF Therm Couple Meters 0 1 amp and 0 2 5 amp 2in diameter 10 post and packing 5 5 C W 0 CARRIAGE CHARGES MAINLAND ONL
149. LYTIC CONDENSERS 2 isats ot pany types trom 0 each SUB MIN TRANSFORMER Output 3 Q for OC72 etc 2 9 driver 8 up to 8 either 1 MULTIMETER 20 000 Q V D C 4 12 6 2 6 10000 V 47 6 2 6 Full details both in list SOLDERING IRON Slim Mod British High speed 8iin all parts replaceable fully guaranteed for profeasional radio and general D 1 Y use 21 1 6 DIAMOND STYLII2 2scenente for BSR TC8LP TC8 8 and TC8LP STEREO COLLARO O RONETTE BF40LP GARRARDGC2LP and GC8LP ACOS GP65 67 ail at 7 6 each 1 ACOS GP73 and GP91 BSR ST4 ST3 BT5 STS ST9 BONOTONE 8TA 9TA and 9TAHC PHILIPS AG3306 3060 3063 3066 3301 3302 3304 ali at 15 1 All are of the very highest quality DOUBLE DIAMOND Types If you don t use the 78 side this is the best buy now available only in 8T4 ST3 ST5 ST9 ST8 9TA 9TAHC 3306 GP91 for GP92 93 and 94 Cartridges and GP918C for GP918C cartridges 80 each 1 SAPPHIRE all the above 7 6 types only also ACOS GP37 at 8 8 each 1 ACOS GP9L at 7 6 1 No other types at present and no 78 rpm available in any type PICK UP CARTRIDGES All fitted Styli and Standard fittings Mono GP67 2 15 8tereo compatible Mono which also playa Stereo records monauraily with min wear GP91 8C 21 latest Stereo GP98 25 6 Q Ceramic Stereo top quality for expensive outfits GP94 88 6 Sonotone stereo 9TAHC diamond fitted cartridge 85 all at 1 More diamond types
150. LYTICS CAN TYPES 9 380V 2 6 100 25V 2 16 16 500V 11 4 350V 2 8 250 88V 2 6 60 60 8500 T 8 450V 2 6 500 25V 4 60 1100 350V 1L6 18 450V 8 8 8 450V 8 8 32 1 82 250V 8 6 32 450V 4 8 Syn 4 82 82 450V 6 8 25 25V 2 18 18 450V 5 82 82 1 82 350V 8 9 50 50V 2 82 82 850V 5 100 50 1 50 350V 9 6 SUB MIN ELECTROLYTICS 1 2 4 5 8 16 25 80 50 100 200mF 15V 2 500 1000mF 12V 3 6 2000mF 25V 7 CERAMIC 1pF to 0 01 mF 9d Silver Mica 2 to 5000pF 9d PAPER 350V 0 1 9d 0 5 2 6 ImF 3 2mF 150V 3 500V 0 001 to 0 05 Od 0 1 1 0 25 1 6 0 47 5 1 000V 0 001 0 0082 6 0047 0 01 0 02 1 6 0 047 0 1 2 6 SILVER MICA Close tolerance 1 2 2 b00p 1 8 560 2 200 pF 2 2 700 5 600pF 4 6 800pF 0 01 mtd 6 each TWIN GANG 0 0 208pF 176pF 11 Slow motion drive 365 865 with 25 Baad H 11 500p slow motion standard 9 small 8 gang 500p 93 SHORT WAVE Single 25pF 11 CHROME TELESCOPIC AERIAL swivel base 28in 5 TUNING Solid dielectric 100pF 800pF 500pF 7 each TRIMMERS Compression 80 50 70pF 1 100pF 150pF 1 8 250pF 1 6 G00pF 750pF 2 1000 pF 2 8 RECTIFIERS CONTACT COOLED wave 60mA 7 6 85mA 9 6 SILICON BYZ18 6 BY100 10 Full wave Bridge Rectifiers 75mA 10 150mA 19 8 EX GOVERNMENT RECTIFIERS 250v 200mA 6 NEON PANEL INDICATORS 250V AC DC Red or Amber 4 RESISTORS Preferred va
151. M BEAT FREQUENCY OSCILLATORS 0 40 ko s 220 Carr 80 G W SMITH amp CO RADIO LTD Also s e next two pages SEMI CONDUCTORS VALVES BRAND NEW amp FULLY GUARANTEED TRANSISTORS IN914 IN4001 IN4002 IN4003 IN4004 IN4005 IN4006 IN4007 IN4148 IN5054 23301 28302 2303 26306 28308 26309 28371 26374 23381 2N696 2N697 2N698 2N706 2N706A 2N708 2N914 2N916 2N918 2N929 2N930 2N1131 2N1132 2N1302 2N1308 2N1304 2N1305 2N1308 2N1307 2N1308 2N1309 2N1613 2N1711 2N1889 2N1893 2N2147 14 8 2N2160 11 6 2N2193 9 6 2N2217 5 6 2N2218 6 6 2N2219 6 6 2N2308 3 6 2N2369 3 6 2N2369A 4 2N2484 6 6 2N2613 7 2N2646 11 6 9N9904 7 2N2923 3 8 2N2924 3 6 2N2925 3 6 2N2926G 2 9 QN2996Y 8 6 9N29260 9 6 2N3053 5j 2N3054 11 2N3055 15 2N3391A 6 2N3416 7 6 2N3570 1716 2N3702 2N3703 2N3704 2N3705 2N3706 2N3707 2N3708 2N3709 2N3710 2N3711 2N3819 2N3903 2N3904 2N3905 2N3906 2N4058 2N4059 2N4061 2N 4062 2N 4286 2N4287 2N 4288 2N4289 2N4290 2N4291 2N 4292 2Nb5354 2N5355 28102 28103 28104 40250 40361 40362 AC107 ACI26 ACI27 ACI28 ACI54 4 6 ACIT6 j ACI87 12 6 ACI88 7 6 ACYM 5 6 ACY18 ACY19 ACY20 ACY21 AC 22 ACY28 ACY40 AD140 AD149 AD161 AD162 AFl14 AF115 AF116 AF117 5 AF118 AF119 AF124 AF126 AF127 AF139 AF178 AF180 AF181 AF186 AF239 ASY26 ASY27 ASY28 48217 AUY10 80 BAY31 1 6 BCl07 8 BCIO8 8 BC109 BCll3
152. N5175 10 8 ASY26 5 RBFWb9 5 MJ490 32 6 ocp7i 8 8 STA 42 6 RULDA 220 Dat and APD a g 2N2646 11 6 2N5176 9 ASY27 7 8 BFW60 b MJ421 22 6 ORPI2 12 6 2N2696 68 8 2N5232 5 6 ASY28 5 6 BFWol 9 6 MJ430 20 6 ORP61 10 THYRISTORS CAPACITORS 2N2711 5 2N5232A 6 ASY 9 5 6 BFX12 4 6 MJ440 19 6 P346A 4 6 PIV 50 100 200 300 400 A large and comprehensive 2N2712 B 2N5245 9 ASY36 5 BFX13 4 6 MJ480 19 6 TIPSIA 16 6 IA 5r 5 6 7 6 8 9 6 range available Electrolytic 2N9713 5 6 2N5246 8 6 ASY50 5 BFX29 6 MJ481 25 TIP32A 19 8 3A 6 7 6 8 9 10 6 Polyester Ceramic Poly 2N2714 6 2N5249 18 8 ASY54 5 BFX30 6 MJ490 20 T1834 12 6 5A A 13j 15 styrene Silver Mica Tantalum 2N2865 19 6 2N5265 65 ASY86 6 6 BFX43 7 6 MJ491 27 6 TIS43 8 7A lif 13 19 6 Trimmers Tuners 2N2904 86 2N5266 5 ASZ20 7 8 BFX44 9 6 MJ1800 43 6 TIS44 2 6 Also 12A 100 PIV 15 600 Examples 2N2904A 6 6 2N5267 52 6 ASZ21 8 6 BFX68 13 8 MJR340 12 6 TIS45 2 6 PIV 85 6 25A 400 PIV 37 6 2 000mF 25V 8 6 2N2905 7 8 2N5305 7 6 AUYIO 80 BFX68A 13 6 MJE520 17 6 T1846 2 6 2 500mF 50V 18 6 2N2905A 8j 2N5306 8 BCl07 2 8 BFX84 5j MJES21 17 6 TI847 2 86 VEROBOARD 3 000mF 25V 10 6 2N2908 5 2N5307 7 6 BC108 2 8 BFX85 6 6 MPFI02 8 6 TIS48 2 6 015 01 5 000mF 50V 19 6 2N9906A 5 6 2N5308 7 8 BC109 2 8 BFX86 5 MPF103 7 6 TIS49 2 6 Matrix Matriz 2N9907 8 2N5309 12 6 BCll3 5 6 BFX87 5 6 MPF104 7 6 TIS50 8 8 o x 3 in 3 8 4 WIRE WOUND RESI
153. ND FLAT SQUARE OR HEXAGONAL MAINS UNIT FOR ALL TRAN PARTS Satisfaction or Refund of Fee SISTOR RADIOS ETC USING s Write foi c f this valuable booklet it may PP3 TYPE BATTERY 20 P amp P TWIN VICE 5 18 0 4 6 P amp P well rore do BRE wining point iA yoUr Cites ALSO AVAILABLE FOR 6V 2 ALSO AVAILABLE Founded 1885 Over 150 000 successes Ali unit letely isolated f ains b SINGLE VICE 3 7 6 3 P amp P double wound transformer ensuring 10 97 safety COVENTRY MOVEMENT CO LTD CHA MBERS COLLEGE Incorp National Inet of Engineering Dept R15 Aldermaston Court Reading RG7 4PF BURNSALL ROAD COVENTRY R 6 S PRODUCTS RADIO LTD CV5 6BU STD 0203 74363 Dept P W 31 Oliver Road London E 17 608 eed tuner Good looks apart the ST 20 offers outstanding performance equal to am plifiers selling at two or three times the price which makes it one of the best buys on the High Fidelity market All silicon solid state circuitry using 20 transistors and 2 diodes provides a full 20 watts r m s output 10 watts r m s per channel Conservatively rated components are used throughout to ensure long term reliability and stability Press button selector switches are a feature of the ST 20 for magnetic phono crystal phono radio tuner tape mono stereo and on off facilities The slimline cabinet in teak veneers and the front panel fascia of ud M iss
154. NDON W1 Tel LANgham 403 Open all day Saturday Z amp AERO SERVICES LTD Please send all correspondence and Mail Orders to the Head Office When sending cash with order please include 2 6 in for postage and handling MINIMUM CHARGE 2 6 No C O D orders accepted PLEASE NOTE THAT THE VALVES OFFERED BEI OW ARE NOT NECESSARILY OF U K ORIGIN PLEASE NOTE THAT ALL PRICES ARE IN DECIMAL PARTS OF I E IN NEW PENCE 6EJ7T 6EW6 6F1 6F5 6F6G 6F1L 6F13 6Fl4 6F15 6F18 6F23 6F94 6F26 6F26 6F28 654 6J5GT 6J7 6K6GT 6K7 6K8G 6K23 6K25 6L6GT 6L7 6L18 6LD90 6N7GT 6P1 6P28 6Q7 6SA7 68Q7 0 35 68K7 0 85 68L70T0 35 6SN7GTO 35 68Q7 0 40 68R7 0 40 6T8 0 35 6U4GT 0 60 6U8A 0 40 6V6GT 0 88 6X4 0 30 6X5GT 0 35 6x8 0 55 TRANSISTORS Quantity prices quoted on request 0 17 98004 1 00 BCY34 28034 1 00 BCY72 28102 0 40 BCZ11 28104 0 50 BD121 28701 0 50 BD123 29702 0 50 BF115 28746 0 90 BF167 ACII3 0 15 BFI73 AC125 0 30 BFI81 AC126 0 25 BF184 AUI27 0 20 BF185 ACI 8 0 20 BF194 ACID3 0 25 BF195 AC154 015 Bp196 AC157 0 20 BF197 ACI69 0 10 BFX88 AC176 0 25 BFY17 ACI87 030 BFYI9 AC188 0 30 BFY50 ACY17 0 30 BFY51 ACY18 0 20 BFY52 ACY19 0 25 B8Y26 ACY20 0 20 BSY27 ACY2L 0 20 B8Y28 ACY22 0 15 BSY65 AD140 0 80 BSY95A ADI49 0 50 OC16 ADISI 0 35 OC22 ADIG2 0 35 0G23 AFLI4 0 25 ocad AF115 0C95 AF116 0C926 AF117 0C98 AF118 OC29 AF125 O0C30 AF126 OC35 A
155. OCI70 4 6 READERS RADIO 85 TORQUAY GARDENS REDBRIDGE ILFORD ESSEX Tel 01 550 7441 Postage on 1 valve 9d extra On 2 valves or more postage 6d per valve extra Any Parcel Insured against Datnage in Transit 6d extra TRANSISTORISED STEREO HI FI RECORD PLAYER Build your own Hi Fi Record Player with the Suraneds fully transistorisad ampli ier which comes compl with 2 10 x 6 spe latest BSR 4 Spei Sterso Mono Record Changer Advanced solid state amplifier only 44 deep 14 transistors plus 4 diodes separate Bass and Treble 10 watts total power Frequency response 15 000 c s P EASY TO INSTALL FANTASTIC BARGAIN OFFER TRANSCONTINENTAL FULLY TRANSISTORISED STEREOPHONIC RADIOGRAM CHASSIS Complete with 2 10 x 6 speakers and the latest BSR Mono Stereo Record Changer a complete tadiogram at half normal price ONLY 10 Watts Total output 38 Gns PAP a 17 Transistors amp 10 diodes 17 6 EASILY FITTED ND TECHNICAL KNOWLEDGE NECESSARY Credit Terms avallable First monthly payment 4 9 18 tollowed by 9 monthly payments of 4 9 10 Total Credit S Price KNOWLEOGE E NO TERRE 3 44 10 4 Send 5 7 4 o 28 Ne s Credit terms available first monthly payment 3 6 2 followed by 9 monthly payments of 3 62 Total Credit Sale Price 33 1 8 Send 4 3 8 today Callers Welcome P EE us um ED EN N
156. ODUCTS LTD pws St Lawrence House Broad Street Bristol BS1 2HF Please send me full details of all Radionic Kits please send me one Radionic Kit X30 for which enclose 7 19s 6d delete where inapplicable E Name uo Address RADIONIC SR ETE ieee MICRO SOLDERING INSTRUMENTS A range of micro soldering instruments combining high performance with really small dimensions and providing exceptional versatility Weighing about oz less flex these miniature tools ensure the utmost accuracy and safety in use resulting in consistently high standards of soldering with minimum operator fatigue Ultra slim unbreakable nylon handles give a cool comfortable grip for sustained delicacy of operation Slip on bits are fitted over the element shaft so absorbing all the heat produced and giving high performance E with rapid heating and recovery A wide range of interchangeable tip sizes is available to suit different types of work There are ADAMIN models from 8 to 24 watts in voltages from 6v to 240v Please ask for leaflet A 10 LIGHT SOLDERING DEVELOPMENTS LTD 28 Sydenham Road Croydon CR9 2LL Telephone 01 688 8589 and 4559 List Price TURNTABLES BASES amp COVERS MacDonald MP60 wired to F CAVE TOP DISCOUNTS Cave s Cash Price din standard withp amp c 2316 4 20 0 MacDonald 610 wired to din standard withp amp c 2715
157. OJECTS ONLY BE ENORMOUS DEMAND FOR THIS NEW DESIGN IN UNDER ONE HOUR You can t go wrong no soldering you get pictorial easy as a b c step by SEND NOW ONLY 47 6 for all parts incluaing case stylus signalling Lights ware mats Sen DUI West tandan n PARTS AVAIL NICELY BOXED MAKES THRILLING CHRISTMAS ABLE SEPA LY E ECTIONS WITH EACH 0 a k tee MONEY BACK GUARANTEE F THE PROJECTS PRESENT Money back guarantee opc GUAB ANE ICIS o gt nM se EN M ae e oe ae eee ee FIND BURIED TREASURE UNIQUE RADIO FOR BEDROOM OR OFFICE TREASURE LOCATOR Ne DASHen no electricity never FULLY TRAN SISTORIZED Tune in your favourite programmes or the news or sports in the Office or in your bedroom Uses sensitive germanium diode origmally evolved step simple instructions ONLY 57 6d 6 6d P amp P for all parts including chassis switches 47 6 nuts screws wire etc etc parts available separately NOW IT S HERE AT LAST aiter experimenting for four and a from Wartime radar Never buy a battery Never use electricity Never half months with a multitude of different circuits and carrying replace Covers all medium waves Clear beautiful tone Size ONLY out actual field tests with prototypes our design team have come 41 x 22 x 13 in beautiful case ONLY 7 CONNECTIONS up with this real winner This fully portable transistorized metal AND IT S WORKING No soldering necessary CAN BE 9 6 locator detects and trac
158. OSCOPE TYPE CT 52 A very handy minia ture portable inatru ment for general purpose a tions 21in diam ELECTRIC CLOCK MOTOR A Met foi NEW 200 250V 60Hz 2W Synchron investigation from ous induction motor 2 revs per hour 10Hz 20MHz Pulse OJP shatt in dia x jin long Clock monitoring duration 50 microseconde to wise rotation Three holed mounting at 0 1 microsecond Time base free running 120 on 2in PCD Price 20 P amp P 5 10Hz 40kHz Also single aweep faciiity from 50 microseconds to 3 microseconds DELAY LINE Y Amplifier Delay Line Calibration Voltage Power supply 110 250V 2 microsecond 4 000 ohm Type MON 2484D Length 24in x fin x iin 40 60Hz 60W Snpplied with metal carrying case L 13in H 8in W 53in Encapeulated module Price 39 P amp P 5j Weight 144Ib Price 22 P amp P 30 MINIATURE SQUARE COUNTER 6 DIGIT By Veeder Root Rotary ratchet type adds 1 count for each 36 movement of shaft 9 6 plue 2 6 P amp P MINIATURE MOVING COIL RELAY 5115 4 DIGIT NON RESETTABLE COUNTER Totalising 10 impulses per second Length 3jin x lin x 1fin 24V d c 300 ohm Price 6 8 P amp P 5 By Sangamo Wes ton euitable for D C circuit A high sensitivity relay more eeneltive than the electromagnetic type Bingle Coil Resistance 310 micro amps 3150 List price
159. PRACTICAL ie n ias ai p f P j DECEMBER 1970 36 174 ome ADCOLA Soldering Instruments add te your efficiency ADCOLA 64 for Factory Bench Line Assembly Aprecision instrument supplied with standard 3 16 4 75 mm diameter detachable copper chisel face bit Standard temp 360 c at 23 watts Special temps from 250 c 410 c Additional Stock Bits illustrated available COPPER D EE B38 4 32mm CHISEL FACE LL LAW S B14 3S 24mm CHISEL FACE CT CREE 4 e SCREWDRIVER B 24 4 75 mm PRCE 4 75 mm EYELET BIT B58 4 634 mm CHISEL FACE LONG LIFE B42 LL 475mm CHISEL FACE B38LL i 32mmn CHISEL FACE E B14 LL 3 24mm CHISEL FACE B 44 LL d 475 mm SCREWDRIVER Don t take chances We don t Ali our ADCOLA Soldering Instruments are of impeccable quality You can depend on ADCOLA day after day That s why they re so popular You get consistent good service relia bility from our famous therm ally controlled ADCOLA Element and the tough steel construction of this ideal production tool Write for D C O L price list TER and catalogue ADCOLA PRODUCTS LTD Dept M ADCOLA HOUSE GAUDEN RD LONDON S W 4 Telephone 01 622 0291 3 Telegrams Soljoint London Telex eTelex Adcola London 21851 JACKSON
160. Power Supply Unit 4 19 6 SINCLAIR PROJECT 60 Package deal price 18 GNS P amp P 12 6 Prolect 60 is supplied complete with instruction manual and templates tor plinth mounting SINCLAIR IC 10 INTEGRATED CIRCUIT 10 watt Amplifier Size only 1 x 0 4 x 0 2in A true hi fi amplifler complete with manual giving details of a wide range of applications and instructions Guaranteed 5 years ONLY 59 6 P amp P 1 6 SPECIAL TRANSFORMER FOR OPERATING SINCLAIR IC 10 from A C mains 230 250v Output 13v at 0 5amp 16 6 P amp P 2 6 HI TEN LOUDSPEAKER British made full range 10 unit handles up to f 10W Ceramic magnet fj Frequency response ff 40Hz 10kHz imp 150 flux density 10 000 lines 49 6 P amp P 4 6 HJ TONE RECORDING TAPE BRITISH MADE TOP QUALITY 31001 L P PVC 225ft 5 6 31002 Poly 600ft 10 6 31003 PVC 900tt 10 J1004 Poly 1200tt 15 31005 PVC 1200ft 12 6 31006 Poly 1800tt 22 6 J1007 PVC 1200tt 12 6 31008 PVC 1800ft 17 6 J1009 Poly 2400ft 25 31010 T P Poly 3600ft 50 C60 Cassette Library cased 8 6 C90 Cassette Library cased 13 C120 Cassette Lihrary cased 18 4 v er2opur LET Boos Aan aoo Ss Shy hy ad LE RP Rr Re Ge Re R Be Be Re Rr Be er Re Poth oA dg mm rM ti STATE natal RED EFFECT RADIO SIE Aaron Listen to all your favourlte radio programmes anywhere and anytime Lightweight and comfortable to wear Covera full m
161. Q Volt A C D C Volte 0 0 5 10 50 250 1 000V A Volts 0 2 5 10 50 250 1 000V D C Currents 0 0 05 0 5 5 50 500mA 10 amp Resistance 0 5K 50K 0 600K 6 MEGQ Decibela 20 to 4 52db 11 10 0 P amp P 3 6 ranges mirror scale 50K Vol D C 6K Volt AC D C Volta 125 25 1 25 2 5 5 10 25 50 125 250 500 1000V A C Volta 1 5 3 5 10 25 50 125 250 500 1000V D C Current 25 B0uA 2 5 5 25 50 250 6U0mA 5 10 amp Resiatance 10K 100K 1 MEG 10 MEGQ Decibels 20 to 41 5 DB 8 17 6 P amp P 3 6 TE 900 20 0000 VOLT GIANT MULTIMETER Mirror scale and overload protection in ful view f meter 2 colour scale 0 2 5 10 250 1 000 5 000 v A C MODEL AS 100D 100K Qj Volt 5in mirror scale Built in meter protection 0 3 12 60 120 300 800 1 200 v D C 0 6 30 120 300 600 v A C TE 16A Trauasistorised Signal Generator 5 ranges 400kHz 30mHz An inexpensive instrument the handyman Operates on 9v battery Wide easy to read scale 5k x 5i x 3 in Complete with instruc tions d leads 7 19 6 Al BELCO DA 20 SOLID STATE DECADE AUDIO OSCILLATOR New high quality port able instrument Sine 1 Hz io 100 KHz Bquare 20 Hz to 20 KHz Output max 10 dB 10 K ohms Opera tion 9220 240v A C Size 215mm x 160mm x 120mm Price 227 10 0 Carr 5j A C VOLTMETER 10 meg
162. R TRANSFORMERS Input 200 250v for 6 or 12v 1 amp 24 4 amp 38 FULL WAVE BRIDGE CHARGER RECTIFIERS 6 or 12 v outputs 14 amp 8 8 amp 11 4 amp 17 COAXIAL PLUG 1 3 PANEL SOCKETS 1 8 LINE 2 6 OUTLET BOXES SURFACE OR FLUSH 5 BALANCED TWIN FEEDERS 1 yd 80 ohms or 800 ohms JACK SOCKET Bid open cironit 2 6 closed circuit 4 6 Chrome Lead Socket 7 6 Phono Plugs 1 Phono Socket 1 JACK PLUGS Std Chrome 8 8 5mm Chrome 2 6 DIN SOCKETS Chassis 8 pin 1 6 5 pin 2 DIN SOCKETS Lead 8 pin 3 8 5 pin 5 DIN PLUGS 3 pin 3 6 5 pin 5 VALVE HOLDERS 1 CERAMIC 1 6 CANS 1 E M i 133 x LOUDSPEAKERS With flared tweeter cone and ceramic magnet 10 watts Bass res 45 60 cps 45 I Flux 10 000 gauss State 8 or 8 or 15 ohm Post 2 6 each Also with twin tweeters With crossover 10 watt State 8 or 8 or 15 ohm Post 2 6 each Recommended Teak Cabinet 5 Size 16 x 10 x 9in Post 2 8 MINI MODULE LOUDSPEAKER KIT 1o warr 65 CARRIAGE 5 Triple speaker system combining on ready cut baffe in chipboard 15 in x 81 in Separate Bass Middle and Treble loudspeakers and crossover condenser The heavy duty B in Bass Wooler unit has a low resonance cone The mid Range unit is specially designed to add drive to the middle register and the tweeter recreates the top end o the musical spectrum Total response 20 15 000 cps Full instructions for 8 or 8 ohm TEAK VENEERED BOOKSHELF ENCLOSURE
163. RV E RS O N S U R P L U S co 2 LT D 2 Please write clearly tested with good quality output transformer PLEASE NOTE P amp P FEW ONLY 55 ee P Early closing Wed I p m 170 HIGH ST MERTON LONDON S W 19 Tel 01 540 3985 CHARGES QUOTED APPLY BARGAIN PRICE ONLY P amp P ON A few minutes from South Wimble UN AA SEND STAMPED ADDRESSED ENVELOPE WITH ALL ENQUIRIES yee ae A ESET E AMPLIFIER HA34 MK II Designed for Hi Fi reproduc tion of records A C Mains operation Ready built on plated heavy gauge metal chassis size 74 w x 4 d x 43 h Incorporates ECC83 EL84 EZ80 valves Heavy duty double wound mains e HIGH GRADE COPPER LAMINATE BOARDS 8 x 6 x hin FIVE for 10 P amp P 2 664 Frequency Multiplier Provided that the output tuning capacitor C of the frequency multiplier stage has a value of at least 100pF it is possible to reduce the value of the associated inductor L Fig 2 until the circuit is resonating at 20 metres with the capacitor at almost its maximum capacitance It will then be found possible to tune the circuit to the 15 metre band and to the 10 metre band when the capacitor is almost at its minimum value FM BA FD 20 15 10 metres A 40 20metres Fig 2 Adding a 20m tuned circuit to the buffer amplifier stage In s
164. S Dept P W 40 41 MONARCH PARADE LONDON ROAD MITCHAM SURREY 01 648 4884 684 RADIO CONSTRUCTOR IN NOVEMBER ISSUE THE DOORCOM This simple but effective transistorised unit allows loudspeaker communication between one Master and two Slave positions If desired both Slave positions may be switched into the system at the same time Printed circuit board assembly SPECIAL WORKSHOP x EQUIPMENT OFFER PLUS MANY OTHER PROJECTS AND FEATURES DATA SHEET No 44 ONSALE NOW 3 6 Copies may also be obtained direct from the Publishers 4 including postage Published by Data Publications Ltd 57 Maida Vale London W 9 RADIO CONSTRUCTOR THORNBURY TRADE DISPOSALS BRADFORD 5 TELEVISIONS 5 Delivered anywhere in Great Britain 17 12 channel Complete amp tested Excellent condition Carriage and ins 1 17 Untested T V s 12 channel 30 Carriage 1 All makes TUBES TUBES Guaranteed 6 months 17 amp 19 All makes 998 was 50 19 Bonde 70j 23 Bonded 4425 24 98 108 eto aso 90 Plus 10 carriage SPEAKERS P M 3 Ohm PERFECT CONDITION EX T V 5 Round Q 6 x 4 9j 7 x 4 4j VALVES EX EQUIPMENT Guaranteed 6 months APRI2 1j PCC84 1 6 PL36 4 6 688 1 EB91 3d PCF80 1 6 PL8L 3 6 68W7 9j EBF89 2 6 PCC89 2 6 PY81 1j 6U4 3 6 ECC82 2 8 PCL85 4 8 PY800 3 20D1 2 86 ECL80 1 PCLR4 8 60 PY82 1j 90P
165. SONIC SOUND These small units contain the OPERATED LIGHT DISPLAY following components 700 ohm DPDT relay with base luF 260v The unit is connected directly across the speaker output of an amplifier it will paper 0 014F 400v paper 50uF then convert audio signals into a spectacular three colour psychedelic light display SEND 8 A E FOR FURTHER DETAILS poe slecbrolytie 2 diodes oco nistor unmarked a skeleton pre set SEND IN S A E WITH YOUR LIST OF COM Bt cone eree Mil housed ina PONENTS FROM THE CONSTRUCTIONAL sizes x5 x3 high 500 watts PROJECTS OUT OF PRACTICAL WIRELESS each channel light output A total ELECTRONICS FOR A RETURN OF POST of 15 x 100 watt lamps can be used of 4 core screen All housed in a Input jack socket Controls vary small neat metal box Can be made into many timing devices 12 Plus 1 6 P amp P QUOTE the input to each channel FLICK ono HP nylon Rogge WE STILL ARE THE LARGEST com 18 10 0 each SWITCHES 3 67 5 PONENT STOCKIST IN LONDON m at ome First Class Radio m n Coi irses we T After brief viei interesting study undertaken at home in your spare time YOU can secure a recognised qualification or extend your knowledge of Radio and TV Let us show you how FREE GUIDE The New Free Guide contains 120 pages of information of the greatest importance to both the amateur and the man employed in the radio industry Chambers Co
166. SS BUTTON D P 8 T 1 9 G P 0 RELAYS EX UNITS 400 Ohms Doz 10 P P 5 Sample 1 8 P P 1 6 SPECIAL OFFER Bush 17 T V Sets Series 75 12 Channels Compiete and Tested with good Tube 6 10 0 Cabinct Fair Carriage and Insurance Passenger Train G B only 35 Untested 17 T V Complete 12 Channel 50 Carriage 1 Speakers Removed from T V Seta All P M 3 Ohms 5 round 8 each 6 x 4 8 e ach 7 x 4 5 each Blot Speakers 8 x 2 5 each Post on any Speaker 4 8 P M Speakers in Cabinet with Volume Control 3 Ohm Cabinet Condition Poor Speaker First Class 10 Post and Packing L0 Reclauned T V Tubes with 6 month Guarantee 17 AW 43 80 AW 43 88 40 MW 43 69 30 each All Tubes 15 Carriage VALVE LIST Ex Equipment 3 months guarantee Single Valves Post 7d over 3 Valves p amp p paid ARP12 1 6 PCL amp 5 4j 6B8 1 8 ERB91 od kvies 4 6BW7 8 6 BESS gi Eris4 4j 6K7 1 9 EBF80 8j PCLB82 4j 6U4 5 ECC8L PCL83 Bj 6P28 5 Ecce 8 PL36 5 10P13 2 8 ECCS3 4 PL81 4j 185BT 8 6 ECL8O 1 6 Py33 5 20D1 3 EF60 1 PYB8Sl 1 6 20P1 5j EF80 ye PY82 3 6 2023 9 6 EFOl od PZ30 5j 30PLI 85 EY86 5j v191 5j 30P12 5 PCC84 2j U 81 5j 80F5 2 6 PCF80 2 U282 5i 41a 5 PCL84 4j lus 5j 6 30L2 5 Head Office and Warehouse 4A WESTBOURNE GROVE LONDON W2 Tel PARK 5841 2 3 Retall Shop 85 TOTTENHAM COURT ROAD LO
167. STORS 2N2923 S3 2N5310 8 6 BOLLS 8 j BFX88 5 MPFIOS 7 6 TIS51 2 6 2 x 5in 4 3 4 9 2 6 watt 5 up to 270 ohms 2N2994 3j 2N5354 5 8 BClloA 7 6 BFX89 12 6 MPB83638 6 6 TIS52 2 8 33 x 3fin 4 3 4 9 only 1 6 2N9925 8 2N5355 5 8 BC1I8 6 6 BFX92A 12 6 NKTOO013 98 8 TIS53 4 6 3 x Sin 5 8 5 8 5 watts up to 8 2kQ only 2 2N2926 2N5356 86 8 BC121 4j BFX93A 14 NKT124 8 6 TIS60 46 34 x 17in 18 216 10 watt 5 up to 25kQ only Green 2 9 2N5365 9 6 BC122 4 BFY10 6 6 NKT125 5 6 TIS61 5 3 x 17in plain 11 6 2 6 Yellow 2 8 2N5366 6 6 BCl25 Il BFYli 8 6 NKTI26 5 6 TIS62 5 6 5 x 17in plain 15 8 Orange 2 6 2N5367 11 8 BCI26 1l BFYI2 4 6 NKT128 5 6 ZTX107 3 6 Vero Pins bags POTENTIOMETERS 2N3011 6 2N5457 7 6 BCl34 6 6 BFY13 4 6 NKT135 5 6 ZTX108 3 6 of 50 5j 5i Garton 2N3014 6 6 2N718A 6 BC135 8 6 BFYl 4 8 NKT137 6 6 ZTX109 3 6 Vero Cutter 9 is vote less switch 8 9N3063 5 928005 15 BC138 7 8 BFY18 6 8 NKT210 6 ZTX300 8 6 cing d Li S SEE itch 4 6 2N3054 10 28020 40 BC140 7 8 BFY19 6 6 NKT211 6 ZTX301 3 6 HEAT SINKS Wie an TG NIB 6 2 2N3058 15 28102 10 BC147 6 BFY21 8 6 NKT212 6 ZTX302 4 6 4 8 x 4 x lin Finned for Two ae Gees come us n i 2N3133 6 28103 5j BC148 2 6 BFY24 9 NKT213 6 ZTX303 4 6 TO 3 Trans 9 6 4 8 x 2 x Lin fin Gange Bterco Bots og 2N3134 6 28104 5 BC149 3 8 BFY29 10 NBT ue E HH Finned for qae es TE and Lin 7 6 2N3135 5 28501 6 6 BC152 8 6 BFY30
168. TILE amp COMPACT ALL BAND AERIAL TYPE SM JOYMATCH Peaks throughout medium amp short wave spectrum used with joystick or conventional aerial 5 10 6 5 6 p p G W SMITH amp CO at LONDON 3434 Lisle St WC2 311 Edgware Rd W2 IMHOF S Eddystone Distributors LONDON New Oxford St WC1 LASKY S RADIO at LONDON 207 Edgware Rd 33 Tott Ct Rd 152 153 Fleet St DAVIS amp KAYS Turnpike Pde N15 RSC HI FI CENTRES at BIRMINGHAM Gt Western Pde BRADFORD 10 N Parade DARLINGTON 18 Priestgate DERBY 16 Osmaston Rd EDINBURGH 133 Leith St GLASGOW 326 Argyle St HULL 91 Paragon St LEEDS 5 7 County Pde LEICESTER 32 High St LIVERPOOL 73 Dale St MANCHESTER 60A Oldham St MIDDLESBROUGH Newport Rd NEWCASTLE TYNE 41 Blackett St SHEFFIELD 13 Exchange St LONDON 238 Edgware Rd G3VFA REGO VARIABLE FREQUENCY ANTENNA PARTRIDGE MAKE DX EASY OBTAINABLE FROM ALSO AT ABERDEEN L Hardie George St ASHFORD MIDDX Echelford Coms BATH Ryland Huntley 15 Old Bond St BIRMINGHAM Amateur Electronics Chas H Young Ltd BLACKBURN Holdings Mincing Lane BOURNEMOUTH Forresters Nat RDO BRADFORD Radio Ham Shack Godwin St BRIGHTON Arthur Sallis Gardener St BURNLEY Trafalgar Supplies CARDIFF Wesak Radio Cathays CHELMSFORD Radio Service New St CHESTERFIELD J amp A Tweedy Ltd EDINBURGH F Brown amp Co Geo IV Bdge FRASERBURGH Murray Mackie GLASGOW RME S
169. UF ZSAMZ 7Q7AA 9J2RO 9J2AG N Richardson Bucks reckons that conditions have been good on 144MHz The gear comprises an 8 element Yagi Garex converter PR30 CR7OA tuning 28 30MHz Signals of the a m variety were received from FIAPQ FIBCI FSVH F6ALH ON4RY ONSHH ONSNY PAOCML PAOFHV PAOTLX PAOJHT Solitary sidebands squeaks from GM30XD P HB9ADIJ P PAOFWS November offers a good choice for the contest enthusiast and s w b The diary reads November 7 8th 40 metre phone contest 7 8th two metre c w contest 14 15th top band contest 20 2Ist Malta Independence Day phone c w contest 27 28th CQ world wide DX contest December 6th 2 metre fixed station contest Please note The address for all communications which includes logs for The Amateur Bands is now 14 Maniand Avenue Harpenden Herts Logs in alphabetical order please to arrive by the 15th of the month j 5 T T gt n S NR NR The Editor does not necessarily endorse the views expressed by correspondents Light communication Concerning the article in the June P W concerning the Light Operated Telephone I have some comments to make Some years ago I had cause to experiment with light modu lated beams and whilst doing this I noted the restriction of h f due to the delay in the bulb filament heating and cooling at h f The amplifiers used at this time to drive the bulb were ECC83 6V6 valved units with an output of about 2 3W int
170. V and using appropriate signals from a radio tuner Current consumption pre amplifiers only 2 5 3mA or pick up etc to ensure that the amplifier is ere both pre amplifiers ajama operating correctly on both channels prete Bass lift Treble lift S 15 mei 4 i ILH At RAL 10 i LLL Bi f ao i 4 JHH doc itt oe 14144 i 5 I 2r Amplifier Fig 13 Graph showing effect of the various controls on the amplifier s basic res ponse curve Fig 14 below left Response from tape head input CCIR Fig 15 below right Response l i from magnetic pick up input Hz 100 1000 10900 100kHz RIAA HHH HHT TTT Frequency Hz 100 1000 10K 20K Frequency Hz 100 1000 10K 20K 658 COMET ae Hi Fi DISCOUNT WAREHOUSES All items offered are brand new latest models in manufac turers sealed cartons Fully guaranteed with after sales service Over 1000 items in stock Complete Free price list on request Customers Welcome Open Daily to the public from 9 a m Closed Tuesday 1 p m Mon amp Sat 5
171. W 70W 30 WATT BAILEY AMP PARTS Benaitivity 1 2V for full output into ANQ Trausistors and PCB for one channel 7 5 6 only nett Transistors and PCR for two channels 214 11 only nett Cepacitora and reisstors metal oxide 40 per channel nett Complete unregulated power aupply kit 4 15 0 nett ZENER DIODES 5 full range E24 values 400mW 2 7V to 30V 4 6 each 1W 6 8V to R2V B each 1 5W 47V to 75V 12 each Clip to increase 1 5W rating to 3 watts type 2664 9d CARBON TRACK POTENTIOMETERS long spindles Double wiper ensures minimum nolse level Bingle gang linear 220 N to 2 2M Q Single gang log 4 7KQ to 2MQ Dual gang linear 47K Q to 22MQ Dual gang log SIK Q to 2 2MQ Log antiiog 10K 47K 1MN only Any type with A D P mains switch extra Please note only decades of 10 22 and 47 are available within ranges quoted pe r E a UAR LA CARBON SKELETON PRE SETS Small high quality type PR linear only 100 Q 220 Q 470 Q 1K 2K2 4K7 10K 22K 47K 100K 220K 470K 1M 2M2 5M 10M 2 Verticai or horizontal mounting 1 each COMPONENT DISCOUNTS 10 on orders for components for 5 er more 15 on orders for components for 15 or more No disconnt on nett items POSTAGE AND PACKING Free on ordera over 2 Please add 1 6 If under Overseas orders welcome carriage cbarged at cost THE NEW ELECTROVALUE CATALOGUE 48 pages thousands of itema packed with information generously illustrat
172. WAVE RP long x 3 in wide x 3in deep E ERE ORP12 Cadmium Sulphide advanced circuitry Complete set of parts etc 78 6 rice 85 P 6 H MAINS TRANSFORMER For transistor power supplies E ese Ble j VERY POWERFUL COMPACT Pri 200 240v Sec 9 0 9 at 500mA 14 P amp P 2 6 HARVERSON S SUPER MONO AMPLIFIER Pri 200 240v Sec 12 0 12 at 1 amp 17 6 P amp P 2 6 A super quality gram amplifier using a double wound fully Pri 200 240v Sec 10 0 10 at 2 amp 27 6 P amp P 3 6 isolated mains transformer rectifier and ECL82 triode Tapped Primary 200 220 240v Sec 21 5v at 500mA MOTOR pentode vaive as audio amplifier and power output 32 6 P amp P 2 6 stage Impedance 3 ohms Output approx 3 6 watts BATTERY CHARGER TRANSFORMERS 200 240v in For 12v D C operation Off load consumption approx Volume and tone controls Chassis size only 7in wide put Nominal output for 6 or 12v batteries 3 amps Size 100mA Totally enclosed Quiet in operation with high x 3in deep x Gin high overall AC mains 200 240v starting torque Overall size approx lj L x 13 dia Free shaft 4 dia x 4 L Ideal tor Model Makers etc ONLY 7 6 each P amp P 1 3 or more post free A few 6v versions also available approx 3 x 23 x 21 Brand New Price 21 P amp P 5 Supplied absolutely Brand New completely wired and db S l aaaea E E RMNNM NEM NI L A ELLA d Open soan Monday to H A
173. WC1 opp Chancery Lane Wed Thurs 7 Mon Sat 8 6 691 dal HH BB T P BMH M D Metangit Practical Wireless Classified Advertisements The pre paid rate for classified advertisements is 1 8d per word minimum order 20 box number 1 6d extra Semi displayed setting 6 Os Od per single column inch All cheques postal orders etc to be made payable to PRACTICAL WIRELESS and crossed Lloyds Bank Ltd Treasury notes should always be sent registered post Advertisements together with remittance should be sent to the Classified Advertisement Manager PRACTICAL WIRELESS IPC Magazines Street London E C 4 for insertion in the next available issue Ltd Fleetway House Farringdon MISCELLANEOUS 2WATT TRANSISTOR AMPLIFIERS not a kit Standard 3 ohm output Frequency response 2db from 12 to 12000 cps on board measuring 21 x 34 in Ideal record players etc 22s 6d each pp Is 6d A Manley 13 Randisbourne Gardens Bromley Road London S E 6 TOP TRANSISTORS ACY22 1 9 OC72 1 9 2N2926 1 79 BFY5I 1 9 OC200 1 9 2N3702 1 9 BFY52 1 9 OC201 1 9 2N3703 1 9 BSY27 1 9 OC2O02 1 9 2N3705 1 9 OC45 1 9 ZTX300 1 9 2N3706 1 9 OC7 1 9 2N706 1 9 2N3708 1 9 All the above types are available at 16 for l Brand New Individually Tested unmarked but guaranteed to be within their correct specification or money refunded ANTEX SOLDER IRON A lightweight
174. Woman s Hour comes through with any clarity the locals fore cast rain So the Henries basked in back to Nature silence relying on social encounters for the saving of sanity And guess what the first family that we met included a teenage son who turned out to be a rabid P W fan Intelligent type obviously with a father who works out mathematical prob lems to put himself to sleep and a mother who is as erudite as she is charming But in the course of conversa tion this column was mentioned and Henry had his gaff blown by the little woman who else With painful memories of the chaffing and criticism suffered in his workshop where colleagues have long since peeled off his aliases like gleeful Inquisitors skinning a heretic Henry was loth to stand up manfully and confess I did it But we were soon launched on the sort of conversation that goes do you remember You will be happy to know Mr Editor that in the wilds of N Wales at least Henry s absence was noted and will have no excuse to do it again if only I can find a carrier pigeon to help me make this deadline TO BUILD YOURSELF Backed by after sales service NEW roamer eight mk 1 WITH VARIABLE TONE CONTROL 7 Tunable Wavebands Medium Wave 1 Medium Wave 2 Long Wave BWI 8W2 8W3 and Trawler Band Built in Ferrite Rod Acrial for Medium and Long Waves Five section 22in chrome platea Telescopic aerial for Short Waves c
175. Y A H THACKER Radio Dept HIGH STREET CHESLYN HAY Nr Walsall Staffs If the necessary test equipment is available the amplifier can be checked for overall frequency response input sensitivity and power output The frequency response curves given in Fig 13 14 and 15 were taken from the original amplifier and performance should agree closely with these If an oscilloscope is available the power output can be checked at just below clipping point with an 8 ohm high wattage resistor across each output Clipping when it occurs at just over 25 watts r m s should be quite symmetrical i e the same at top and bottom of the wave form The voltage across an 8 ohm load at just below clipping will be between 14 and 15V r m s The amplifier will of course only develop its maximum power output of 25 watts per channel with 8 ohm loudspeakers Nevertheless the output power of 15 to 18 watts that would be developed across 15 ohm speakers is still quite considerable for a domestic stereo hi fi amplifier At average listening power levels the difference in performance between 8 and 15 ohm speakers would be barely noticeable It is only really necessary to use 8 ohm loudspeakers if one wants the resultant full power with life size sound and thereby run the certain risk of becoming unpopular with neighbours When the amplifier has been finally tested the legends for the controls can be put on with Letraset or similar transfer lettering and a s
176. a highly stable Colpitts circuit voltage stabilised by a zener diode D3 Stability against changes in ambient temperature is achieved by using polystyrene capacitors which offset the positive temperature coefficients of transistor and coil If anything the oscillator may be over compensated and if desired it is not too difficult to be precise by using a combination of polystyrene and silver mica capacitors for C24 The ganged tuning capacitor VCla VCib must be 627 a good one with adequate screening between stators Most capacitors tried had too much stray coupling between sections so that oscillator voltage appeared on the r f section With the capacitor used no oscillator voltage was measurable on the r f section In the prototype this is a Jackson Bros Type F H law but it has later been found that this type can also be supplied in SLF and this is specified as it will provide a linear scale calibration Two methods of improving i f selectivity are adopted ift2 and i f t 3 are connected back to back to provide four tuned circuits instead of the usual two and because of the small amount of coupling the reduced loading results in higher circuit Q s Also Tr3 and Tr4 are each given a small amount of positive feed back via capacitors C11 and C17 respectively These provide only a moderate amount of regeneration well below the point of oscillation but give a marked increase in selectivity The output from the las
177. a i to En n en Oa 1 3 QUA RSAERSSSARASSE LIIS TT21 TT22 U18 20 U25 U26 U31 U37 U52 U76 U78 CrrrorreNnrr in toio 8882855592685 cesseososssse KORMCARMMSSMSMASAS ineo oa EF37A 0 60 EF39 0 40 EF40 0 50 Gl obOuooooo ocoOooooo0oocooc opPoPootf inis go co bo tato to rie rto Da i a sesecserecs COO tea d ue Dt o ie i C0 EN EO DIDS MS was 2N404 2N444A 2N696 2N697 2N698 2N705 2N706 2N708 2N753 2N929 2N930 2N987 2N1131 2N1132 2N1184 2N1301 2N1302 2N1304 2N1305 2N1306 2N1307 2N1308 2N1309 2N1613 2N1711 2N1758 2N2147 S2160 Type U4312 U4313 Type U4812 Low sensi tivity instrument 667 O p V 1 accuracy on DC and 1 5 on AC 9 current ranges on DC 3004A to 6A and 8 current ranges on AC 1 5m4A to 6A 9 voltage ranges 0 3 to 900V AC DC Resistance 0 2 to 30k Q Mirror scale P RICE complete with leads and case 9 15 0 3 in tube fitted with telescopic viewing hood giving bright display in full daylight Bandwidth 10 c s 10 me s Triggered sweep pre set at 1 2 5 10 30 100 300 1000 3000 prec per stroke Free running time base 20 c s to 2000kc s with built in crystal calibrator providing timing marks at 05 2 1 5 20 100 u sec 5 Amptihide calibrator directly calibrated in volts Input attenuator 1 10 100 Power supplies 127 230v AC PRICE 89 00 Packing and carriage 1 50 Type U4318 20 000 o p v DC and 2 000 o p v on AC
178. about 1kO CIRCUIT As can be seen from the circuit diagram in Fig l the tester consists basically of a low frequency free running or astable multivibrator Because the circuit is not exactly symmetrical when the current Fig f Circuit of tester All resistors are 31W 642 supply is completed through the probes the current through one transistor say Trl increases faster than the current through the other The collector voltage of Tr1 will rise to almost zero This voltage change will be fed to the base of Tr2 so reducing its collector current and making its collector voltage more negative This change is fed back to the base of Trl so causing a further increase in the collector current of Trl This re generative action will continue until Trl is hard on and Tr2 cut off Capacitor C1 now charges up through R2 until the base of Tr2 becomes sufficiently negative that Tr2 begins to conduct regenerative feedback causing Tr2 to turn hard on and Trl to cut off C2 now charges up through R3 and the cycle repeats With the values of Cl C2 and R2 R3 given in Fig the circuit oscillates a few times per second causing the bulb in the collector circuit of Tr2 to flash on and off alternating with a pulse of sound from the speaker in the collector circuit of Tr1 CONSTRUCTION Almost any p n p transistors with a collector current rating of about 100mA or more can be used The frequency of oscillation can be varied by altering
179. ac 10 ele 42 14 ele 47 18 ele 85 22 ele 6 tical training in Radio and TV Servicing One year day courses BBO Aerials Dipole 85 X 43 H 48 commencing in Sept January and April are available for ITA Aerials 5 ele 30 8 ele Sj 11 ele 08 beginners and shortened courses for men who have had combisatinn AS iali Dipole plus 5 54j previous training Write for free prospectus to H plus B Si X plus 5 90 Speclal Loft Dipole plus 5 42 London Electronics College Dept LX 4 20 Penywern Diplexers gp Triplexers Matched Diplexers VHF Road Earls Court London S W 5 Tel 01 373 8721 Poles qain Clamps Couplers ete Co Ax and 2 3 Postage paid inland on Aerials only Please state RADIO OFFICER training courses Write channels when ordering BAE for full lists Principal Newport and Monmouthshire TRAIN FOR SUCCESS College of Technology Newport Mon 11 Dale Crescent Tupton Chesterfield WITH ICS Study at home for a progressive post in Radio TV and Electronics Expert tuition for City amp Guilds geo Sa ES Se Be ES Telecoms Techn s Cert and Radio Radiomohile Amateurs R T E B etc Many BRITAIN S CAR RADIO SPECIALISTS non exam courses incl Colour TV SITUATIONS VACANT STEWARTS ROAD LONDON SW8 R T E B Certs City amp Guilds Colour TV Radio Computers Radio Amateurs Cert Practical Electronics with kit Thousands of successes Send for full de tails
180. ad London W2 5AJ PLEASE NOTE MINIMUM ORDER SHOULD BE 10 Quantity Prices 100 Phone 01 Naw Autumn List New devices 723040 Ex 4 All listed devices are New prices Ask for List 36 Send from stock at time of going to press for free copy today Please add 1 6 past packing to your Discounts 10 on 12 any one type order 15 on 25 any one type HENRY S RADIO E NAM Eriugena eeore ree Sete Orr Sere ree rerererr crit es errr ey Full time Course in Radio Television and Elec Idus Mad Order Dept Cumponents O gan Dept 303 EDGWARE ROAD LONDON W 2 Teieopene 01 723 10089 e nar Sae i A DISCOSOUND DISCOSOUND 40 PRE AMP The Discosound 40 offers the same specification as the D J Disco Amp without the power output stage Size l6inx7in x7in Self powered and ideal for use with the Discosound 100 Power Amplifier below and one of the outstanding features is that it is capable of running ten of these Power Amplifiers Total 1 000W PRICE 40 10 0 inc P amp P DISCOSOUND 100 POWER AMPLIFIER A 100W RMS 8 Ohms High Fidelity power Amplifier which utilises all silicon transistors of modular construction and features full automatic overload protection against short or open circuits Frequency response 20 20 000Hza2dB The High output is ideally suited for discotheques groups clubs etc or anywhere where reliability and quality are required This unit is the com
181. akers from 3 to 15 ohms Compact design all parts supplied including drilled metal work high quality ready drilled printed circuit board attractive front panel knobs wire solder nuts bolts no extras to buy Simple step by step instructions enable any constructor to build an amplifier to be proud of Brief specification Power output 8 5 watts r m s per channel into 5 ohms Frequency response 3dB 15 30 000 Hz Sensistivity 50 mV into 1 meg ohm Full power bandwidth 3 dB 20 14 000 Hz Readings taken at 8 5 watts into 5 ohms Bass boost approx to 12d B Treble cut approx to 16dB Negative feedback 18dB over main amp Power requirements 25V at 6 amp PRICES AMPLIFIER KIT 10 10 0 P amp P 3 POWER PACK KIT 88 0 0 P amp P 5 CABINET 83 0 0 P amp P 5 Post Free if all units purchased at same time Also available STEREO 10 10 As above but 10 watts per channel PRICES AMPLIFIER KIT 12 P amp P 3 POWER PACK KIT 3 10 0 P amp P 5 LOUDSPEAKER BARGAINS 3 4 ohm 10 P amp P 1 o Sin 3 ohm 16 P amp P 3 7 x Jin 3 ohm 921 P amp P 4 10 x in 3 or 15 ohm 35 P amp P 6 E M I 8 x Sin 3 ohm with high flux magnet 26 P amp P 4 E M I 134 x 8in 3 obin with high flux ceramic magnet 42 15 ohm 45 P amp P 6 B M I 13 x 8in 3 or 15 ohm with two inbuilt tweeters and crossover network 4 gns P amp P 6 BRAND NEW 12in 15w H D Speaker
182. an be angled and rotated for maximum per formance Push pull output using 600 mW transistors Socket for car aerial Tape record Socket Selectivity switch Switched earplece socket complete with earpiece for private iisten Ing Eight transistors plus 3 diodes Famous make 7in x 4in Speaker Air spaced ganged tuning condeneer On Off switch volume control Wave change switch and tuning control Attractive case in rich chestnut shade with gold blocking Size 9 x 7 x 4in approx Easy to follow instruc tions and diagrama make the Roamer Eight a pleasure to build Total Building Costa 1 9 Parts Price List and Easy Build Pians 5 FREE with parte a a P amp P 7 6 roamer seven mk IV SEVEN FULLY TUNABLE WAVE BANDS8 MW MW LW 8W1 SW2 SW3 and Trawler Band Extra Medium waveband provides easier tuning of Radio Luxembourg etc Built in ferrite rod aeriai for Medium and Long Waves Retractable 4 section 24in chrome plated telescopic aerial for peak Short Wave listening Socket for Car Aerial Powerful push puii output Beven tranelstors and two diodes including Micro Alloy R F Transistors Famous make 7 x Jin P M speaker Air apaced trans eight SIX WAVEBAND PORTABLE WITH 3in SPEAKER Attractive case in black with red grille and cream knobs and d al with polished brass ganged tuning condenser Volume on oft control wave change switches and tuning control Attractive case with carrying ha
183. aptor to fit standard floor stands 29 6 1 6 DYNAMIC Cream hand table 15 6 1 6 MS10 50K OQ 3 x 4 with Base Adaptor 89 6 2 6 MS11 similar but fixed on flexible Swan neck to switch fitted base 42 6 2 6 CARDIOD DYNAMIC OMNI DIRECTIONAL Highly successful BALL type 209 50K 600 ohms imp Built in vol control on off switch special lead handle 26 6 0 Non directional Bal type 50K Q with on off slide switch 20 cable amp connector amp stand holder thread type DM160 3 17 8 on both types 5 MICROPHONE INSERTS Diameter 1 75in or 0 9in either size 5 8 1 SPEAKERS 1 in round fitted Tweeter GW 3 or 15 Q state which 37 6 5 6 or for stereo 80 per pair charges paid 24in 3 Q 7 6 1 Limited quantity powerful 24in PM transistor replacement speaker high ohms excellent 6 1 HEADPHONES Stereo Dyn 8 16 Q 63 3 EARPIECES with lead and min jack plug magnetic 1 8 Crystal 4 9 up to 3 for 1 on either State if 2 5 mm of 3 5mm plug required Crystal 3 5mm only AERIALS CAR TYPES Telescopic vandal proof locks retracted 2 keys and all fittings 27 6 2 6 Superior type slightly longer 30 2 6 Extending Aerials tor Portables amp F M Sets 4 section 63 23 1 sliding threaded base necds hole 4 6 section 541 251 screw hole in base 4 7 section 54 32 screw hole in base 7 8 DISAPPEARING with swivel and sliding threaded socket fixin
184. arch Metrication Constructional A M S E Civ C amp G Structural Road Engineering Civil Engineering Building Air Conditionin Heating amp Ventilating Carpentry amp Joinery Clerk of Works Building Drawing Surveying Painting and Decorating Architecture Builders Quantities Write if you prefer not to cut this page General CELI Petroleum Tech Practical Maths Refrigerator Servicing Rubber Technology Sales Engineer Timber Trade Farm Science Agricultural Eng General Plastics General Certificate of Education Choose from 42 O and A Level subjects including English Chemistry General Science Geology Physics Mathematics Technical Drawing French German Russian Spanish Biology B I E T and its associated schools have recorded well over 10 000 G C E successes at O and A level WE COVER A WIDE RANGE OF TECHNICAL AND PROFESSIONAL EXAMINATIONS other exam successes Over 3 000 of our Students ave obtained City amp Guild Certificates Thousands of Completing your Course meant going from a job I detested to a job I love Case History B 461 FIND OUT FOR YOURSELF These letters and there are many more on file at Aldermaston Court speak of the rewards that come to the man who has given himself the specialised know how employers seek There s no surer way of getting ahead or of opening up new oppor t
185. arr 7 6 B C 221 FREQUENCY METERS latest release 125 KHz 20 MHz Excellent condition Fully tested and checked and complete with calibrator charts 27 10 0 each Carr 10 AM FM SIGNAL GENERATORS Oscillator Test No 2 A high quality precision instru ment made for the ministry by Airmec Frequency coverage 20 80 Me s AM A CW FM Incor porates precision dial level meter precision attenuator lyr V 100mV Operation from 12 volt D C or 0 110 200 250 volt A C Bize 12 x 8 x 9in Supplied in brand new con dition complete with all connectors fully tested 45 Carr 20 AVO CT 38 ELECTRONIC MULTIMETERS High quality 97 range instrument which measures A C and D C Voltage Current Resistance and Power Output Ranges D C volts 260mV 10 000v 10 meg Q il Omeg Q input D C current 10 A 25 amps Ohms 0 1 000 megQ A C volt 100mV 250V with R F measuring head up to 250 Mc s A C current 10 4 25 amps Power output 50 micro watte 5 watts Operation 0 110 200 250V A C Supplied in perfect condition complete with circuit lead and R F probe 25 Carr 15 ADMIRALTY B 40 RECEIVERS High quality 10 valve receiver manufactured by Murphy Coverage in 5 bands 650 Kc a 30 Mc s I F 500 Ke s In corporates 2 R F and 3 LF stages bandpass filter noise limiter crystal controlled B F O calibrator I F output etc Built in speaker output for phones Oper ation 150 230 vol A C Bize 19 x 13 x 16i
186. at the analysis given above assumes accurate switching operation in the full wave gate section of the i e TrI Tr4 so that the Fourier series of sine waves is produced This is obviously dependent on the amplitude of the carrier signal applied to the modulator should this be significantly lower than 300mV the transistors do not switch cleanly with a consequent departure from precise squaring of the waveform and therefore from the Fourier series This implies a residual carrier frequency component to a degree determined by the extent of linear operation in the gate transistors so the circuit output approaches the conventional amplitude modulation Applications For use as a detector of either a m or s s b signals a carrier wave must be supplied in the same way as in the modulator case however this time the carrier is selected to be at the same frequency as the carrier of the signal to be detected In a practical example the signal is delivered by the final if stage of a receiver while the local carrier is generated by the receiver b f o beat frequency oscil lator The sideband will be displaced from the carrier by the amount of the modulation frequency so it follows that if all the high freauency com ponents of the i c output are rejected the system output will be the audio modulation alone Carrier SOKN Carrier null Modulating signal input Operation of the MC1596G as a balanced modulator If
187. ave loading coils ensure excellent tracking sensi SET OF PA tivity and selectivity on both wave bands R F sensitivity at 1 MHz is better than 8 micro volts Power output into 3 ohm speaker is 3 watts Originally sold completely built for 15 4 6 e e Pre aligned I F module and tuner together with plus 7 6 P amp P comprehensive instructions guarantees Success first time 12 volts negative or positive earth or available separately Circuit diagram 2 6 Free with parts Speaker baffle and fixing kit Size Tin x 2in x 44in deep 25 extra plus 4 p amp p Postage oO See top of previous page for address free when ordered with parts ON LM 615 Build working radio receivers and electronic circuits in an evening Beginner or advanced student you learn fast with Radionic kits Circuits work first time with the Radionic no soldering method With the X30 kit build 33 experiments a printed circuit transistor radio burglar alarm morse code buzzer etc The more advanced kits are suitable for G C E City and Guilds National Certificate and higher Every set includes construction notes and all circuit diagrams It so easy for you to build and learn because you construct circuits that resemble the theoretical diagram Re use components easily too they re screw in mounted Send off this coupon today ENE Po A a a I UD UM CE are Be TO RADIONIC PR
188. ave Philips cassette recorder and a Grundig track machine with speeds of 17 32 and 7 I p s Louis Smit 42 Langton Road lontctair Durban South Africa girl with interest in Amateur radio or electronics About 16 years ofd R Colllns 17 Heathfield Chippenham Wilts hear my own age 17 from the Hong Kong Kowloon area who are living in this country already have a pen friend in Causway Bay Hong Kong and know a little about the area My tape speeds are 17 33 and 74 i p s and my hobbies are short wave listening tape recording and photography and electronics A M N Hoare 4 Fair field Drive Whitburn Sunderland Co Durham 80meone of my own age 16 who is interested in electronics and radio have a Ferguson 2 track machine with speeds of 14 and 32 p s R Richards 33 Rogers Road Canning Town London E 16 boy of 13 would like to tapespond at 31 i p s Interested in pop records disc jockeys would like to be disc jockey himselt one day Can send interesting tape to someone own age Reage Preston Jnr 7 Gordon House Tarves Way Greenwich ondon S E 10 ISSUES WANTED dune September and October 1961 and May July and August 1962 issues of Practical Wireless A Giles 20 Fleldway Dagenham Essex borrow only copies of P W for April May and December 1966 J A Foil 104 Burnley Road Rawtenstali Rossendale Lancashire BB4 8HH issues of Practical Electronics containing plans
189. ay Hanwell London W 7 01 567 5400 2971 WE BUY New Vaives and Transistors State price A D A MANUFACTURING CO 116 Alfreton Road Nottingham WANTED NEW VALVES ONLY Must be new and boxed Payment by return WILLIAM CARVIS LTD 103 North Street Leeds 7 WANTED NEW VALVES televisions radioerams transistors etc STAN WILL ETTS 37 High Street West Bromwich Staffs Tel WES 0186 WE BUY New Valves Transistors and clean new components large or small quantities all details quotation by return WALTON S WIRELESS STORES 55 Worcester Street Wolverhampton WANTED Pye Radiotelephones types F27AM Cambridge Bantam Westminster Motaphone Phone Caterham 46692 HIGHEST CASH PRICES for good quality Tape Recorders 9 30 5 00 Immediate quota tions 01 472 2185 o P HI FI EQUIPMENT SHURE GOLDRING Cartridges Post Free G800 M44 5 7 7 17 6 M3D 5 5 0 MME 8 19 6 MSSE 9 19 6 M7SE 2 16 10 0 GARRARD SP25 2 10 17 6 AP 75 16 17 6 p amp p 7 6 Ultimate Electronics 38 Achiles Road London N W 6 Mail Order Only pA d METAL WORK METAL WORK All types cabinets chassis racks etc to your specifications PHIL POTTS METAL WORKS LTD Chapman Street Loughborough EDUCATIONAL AERIALS TELEVISION BAKER AND BAINES m i UHF Aerials BBC and ITV 625 Col This private College provides efficient theoretical and pr
190. base bias Note that if an electrolytic is used for Cl the value of RI may have to be altered to allow for leakage R2 acts as the collector supply and load and the output is coupled via C3 to the volume control VR1 C3 is 0 54F and the same rules apply to it as to Cl that is an electrolytic could be used in its place C4 acts as a d c blocking capacitor and feeds the 678 No 20 MEGAPHONE Tr1 Tr2 Tr3 BC169C BC169C OCc26 Fig 1 The circuit of the Take 20 Megaphone signal to the second transistor Tr2 which like Trl is a BC169C The emitter of Tr2 is connected to the negative line via a 4700 resistor connected through the loudspeaker this tends to d c stabilise the conditions in the output stage A positive feedback loop exists and it is essential that C5 is included to decouple the audio VR2 is a small preset potentio meter which acts as the collector load this sets the quiescent current through the output stage Tr3 An OC26 has been specified for Tr3 but in fact almost any germanium power transistor would do some of those available as unmarked surplus types would do well here The loudspeaker impedance is not all that impor tant and a 30 type has been specified here only because these are more common than others it is however essential that it has a cone diameter of over 6in Speakers with smaller diameters will have their cones biased one way by the quiescent current through the output transistor and wh
191. bled before the boards are wired Fig 7 b Details of metal screens Fig 7 c Location of completed circuit board assemblles Another view of the completed PW25 25 Stereo Amplifier in which the wiring to the Henelec Type PA25 output modules can be seen 653 pJeoq Jayjydwe asd 1nduj Jouueu H y eu UO SEY pZ 40 Ma2xa 4 470 y Jo ebeur JOJU ou SI ouo 1UbH 0 Ya IEY VON spieoq JN Jejfijduje aud y Jo jno ej jueuoduo 8 5 4 Sjewoos 543490S jndui woss yndul wos 3 wo9 aul 3 ue eur 3 wog 3 wos wog 7S uo es uo 1S uo3tS BLY FIA ILAA 81H PIA WLU A JonuUos aouejeq of jou3yuo 2 aouReg 1X8 eas Addi jOdns AGE v S H 22 Spjeoq 419430 uo ses 4 dwe aid jnduI z 7 8 MM 1 amp uu u H H Pesojo peuuJou uedo Ayewsou uedo ApjeuJou pasoj o Ajjewsou jlouueu2 H 1 CHA Ionuo aiqan ol ES yams YS YMS YS u2iMS ES yopms ZUA1041U02 aqa o J93 9 s u OL JM NSIYM OL 48944 AqUWNI OL eq 2 j ejquinJ of zs sisseyd sisseyo 0 128uuo5 0 1280005 Ieuueu Hy PULLI HT 4A 1033002 eu an Kcueu HT gAMA 1041002 e uejeq 1041002 o11uo3 a2uejeq auinjoA auinjoA THAD uM 8 yes GEN 4Z9 daiidwe aAup pue joujuo gt auo puueuD H H e q o5 jeuueu H71 2 q e MA 1000 sseq OL T3NNVHO QNYH 1H9IH T3NNVHO ONVH 1437 EXA Tenuos sseq oi u10Jj wos 654 RH LH
192. boards Next come the wires connecting the selector switch SI and S2 to the input pre amplifier boards Again no screening is necessary providing the leads are as short as possible and are kept clear of the other circuit boards The connections are shown in Fig 10 but note that the pictorial diagrams of the switch wafers may not agree with those actually purchased ie the contacts may be differently orientated The remainder of the wiring is to SIA and B from the input sockets and this includes the input attenuators RI R2 R3 R4 etc The leads between the tape recording output sockets and the output from the pre amplifiers C23 need not be screened but must be as short as possible and kept clear of leads going to the input sockets Those who have test equipment such as an audio 2 Component boards SRBP O15 matrix 2 Component boards S RB P 1 0SWG Aluminium screen O 15 matrix 1 20SWG Aluminium screen 3 This size 3 Uo 1 4 4 Centre 31 9 This size Centre L 2 i 1 1 1 z 1 6 eee b I Las __ Tone contro and drive amplifier Input pre amps Components poate Right hand Lett hand Screen channel Component board input Left hand s channel Right hand channel SSE eT AA A s a f c Input sockets Fig 7 a Mechanical details of the component boards and screen assembly It is strongly recommended that the parts be test assem
193. c design 1mA full scale calibrated 21 high each each P amp P 3j 100 23 M Eg 12 6 1 a 7 6 0 100 21 x 21 x 14 deep 30 Plus 2 6 P amp P SEND F S IMPORTED PANEL METERS p n d KA 38C 11 x 11 504A KA 65C 34 x 34 300v MODEL MAKERS MOTOR COMPONENT CENTRE A EA RASC raw 00v 8 x 6 one sided printed circuit board 8j each 5mA S meter IMA 300v All at BY100 type rectifier 800 piv 750mA_ a Hg cack All at 4 pin transistor holdera 1 eac j 21 80 ahm loudspeaker 4 ze 6 each 29 6 Plus 1 P amp P 39 6 Plus 1 6 P amp P 2i 8 ohm loudspeaker U e 0 6 each All modern design and made to high standards 24 25 ohm Jeadepeaber i bis San s exch U2 battery holders blue p etie s a eac 10 ohm w w pots 2 sits 2 6 each 7 E M I SET 150 OC8 double heat clips 6d each E M l SET 450 This speaker has a flared Tape recorder rev counters R 5 each centre tweeter cone and Rated up to 11 5 volt 400mA torque Transistors Diodes S C R s etc Send for list now MR 65 j 8 or 15 Q 10 watts handles up to 10 watts 12g cm Size 1lj long x i diam Please include P amp P Plus 7 6 P amp P Bize 138 x8 50 each Bhatt v long x jg 4j a 1 6 Send 3 for our Component Catalogue and Flog Lists 3 8 amp 15 ohms 47 8 P amp P ELL TIME UNIT CRESCENT CHROMO
194. chniques G3UQR and G3CWV Further gen from John Bennett G3FWA Hon Sec Beds amp Dis trict A R C 47 Ibbett Close Kempston Bedford Stereo Receiver A new British made stereo receiver is challenging the increas ing sales of importer hi fi sets in the United Kingdom The Rank Wharfedale 100 1 high fidelity tuner and amplifier chalked up more than 100 000 worth of orders within three days of its introduction to the hi fi market At 125 guineas the Wharfedale 100 1 sells for 50 less than the equivalent imported models It locks automatically on to stereo stations and it sets new standards in distortion free reproduction for domestic equipment of this power An interesting innovation is the use of fibre optics bundles of glass filaments which carry light round corners to illumi nate the tuning pointer This is the first application of fibre optics to the sitting room The 100 1 receiver gives a true 35 watt R M S per channel with only 0 1 distortion factor As well as V H F it receives long and medium wave bands Attention Nibblers West Hyde Developments Ltd are now selling a simple hand operated nibbling tool It cuts almost any shaped hole in chassis panels cases etc with a punch and die action so as not to dis tort the material Panels up to 16 gauge aluminium or 18 gauge steel may be cut Price is 64s 6d plus 3s p p Spare punches cost 35s plus p
195. claim that British models comparing with this specification could cost you 140 y CCIAN WORLD BEATER a eee LEARN HOW INTER WORK HTH EAP STIS AN yourself teaching aid designed to TOTRANSISTOR remove the mystery from digital computers logic and Boolean algebra PORTABLE RADIO SPEAKERS 10 24 8Q 3j 250 4 10Q 3 x 5 80 7 x 4 30 8 x 3 30 BRAND NEW P amp P 2 Transistors Mullard matched output Kita tii OC81D 2 OCBI s P amp P Transistor Radio Cases 4 for l Size 94 x 64 x 34 P amp P 9 6 Ferrite Rods 3 6 6 and 8 complete with LW MW Coils P amp P FREE STRIP LIGHT TUBES 3 9 each 11 284mm 230 240 volts 30 watts Ideal for cocktail cabinets illuminating Cloth covered Size 163 x 142 x pictures diffused lighting etc 7i Takes any modern auto 6for l P amp P free changer P amp P 7 6 RECORD PLAYER CABINET 49 6 DUKE amp CO LONDON LTD 21 3 Romford Road London E12 Tel 01 478 6001 2 3 Cheap Quick and Clean and BATTERY MODEL clear winner on all counts tays the 10 N Times Educational Supplement 0 1319 Accompanied by easy to follow REC R E eR instruction book Ario Ma BOX POSTETC 8 6 Ideal as a gift co amateurs intelligent teenagers teachers etc COMPARE Unassembled kit complete Type CK1 U 10 10 0 P amp P 6 5 i i i Assembled f
196. d 2 pos stereo dual ganged volume control 614 selector TONE CONTROL Trebie lift and cut Separate on off switch A preset balance control Duetto integrated transistor stereo Amp 9 10 0 7 6 p amp p Garrard Changer from 7 19 6 7 6 p amp p Cover and teak finish plinth 4 15 0 7 6 p amp p Duo Type speakers see opp page ea 4 4 0 7 6 pap The above items purchased together 29 10 0 1 10 p amp p cC Uwe The ELEGANT SEVEN Mk Ill Of 350m W Output 8 d 7 transistor fully tunable M W L W superhet portable Set of parts Complete with all components including ready etched and drilled printed circuit board back 50 WATT AMPLIFIER amp SPEAKER SYSTEM E BE Biswas pownn PACK KIT 9 6 extra Price 5 5 0 plus 7 6 P amp P Circult 2 6 FREE WITH PARTS The Price 5 5 0 DORSET plus 7 6 P amp P Cireuit 2 6 4 600mW Output FREE WITH PARTS 7 transistor fully tunable M W L W superhet portable with baby alarm facility Set of parts The latest modulised and pre alignment techniques makes this simple to build Sizes 19 x 8 x 3ln MAINS POWER PACK KIT 9 6 extra The Classic Simulated teak case 9 10 Plus P amp P 7 6 SPECIFICATION Sensitivities for 10 watt output at KHz into 3 ohma Tape Head 3 mV at 31 ips Mag P U 2 mV Cer P U 80mV Tuner 100mV Aux l00mV Tape Rec Output Equallsation for each input is correc
197. dB to 15 dB at 50 c s CONTROLS 5 Position Input Selector Bass Treble Vol Bal Ste M Bwi T Monit j HUM LEVEL 80 4B Yol Bil Slereoratono Bwiteh Tape Monitor Swit UNIT FACTORY BUILT 29 Gns HARMONIC DISTORTION 0 195 at 10 watts 1 000 c p s INPUT SOCKETS 1 P U 2 Tape Amp 3 Radio With 12 months guarantee Employing Twin Printed Circuits 4 Mic or Tape Head Operation of Input Selector or Deposit 24 and 9 monthly payments 66 6 Total 200 250v A C mains operation assures appropriate equallsation 33 18 6 or in Teak or Afrormosia veneer hous 326 CRO88 TALK 52 dB at 1 000 c p s CHASSIS Strong Steel construction Approx 12 x 3 ing Carr 15 Terms Deposlt 24 and 9 moath ns j p s x 8in ly payments of 74 Total 37 8 0 Send S A E for leaflet BRADFORD 10 North Parade Half day Wed Tel 25349 BLACKPOOL Agent O amp C Electronics 227 Church 32 High Street Half day Thurs Tel 56420 LEICESTER uren 5 7 County Mecca Arcade Briggate Hat day br LEEDS BIRMINGHAM 9 Gt Western Arcade Half day HI FI CENTRES LTD 73 Dale St Half day Wed Tel CENtral LIVERPOOL DERBY 26 Osmaston Rd The Spot Half day Wed Tel MAIL ORDERS TO Audio House 238 Edgware Road W2 Half day Thurs Tel LONDON 41361 Henconner Lane Leeds 13 PAD 1629 DARLINGTON ts Priestgate Hatt day Wed Tel 68043 N pentane ala ona under 2 SON Oldham Stress Meene 2378 MANCHESTER EDI NBURGH 133 Leith St Half day
198. e Stereo 10 10 Compact System Expertly designed and providing outstanding quality reproduction Not just another compact system but a true sound centre incorporating an all silicon transistor amplifier Garrard 3000 autochanger and two Metrosound HFS 10 speaker systems Output 20 watts rms 10 watts rms per channel Bass Treble Volume and Balance controls Input for tuner Tape record outlet Price 77 6 4 Please send full details of ST 20 Amplifier 110 10 Compact C Speakers NAME ADDRESS ai eter cte obey ics i 1 xtal mag gum mcm gm K Lol IVletrosound Audio lape mono oN PA brushed anodised aluminium finish with gleaming silver trims combine to give a look of expensive and stylish elegance Size 1537 x 33 x 10 Price 36 0 0 DESIGN CENTRE LONDON Its performance is not just on the fringe of the specification as happens with many low priced amplifiers it is well within it and well within the require ments for hi fi F C Judd Hi Fi Sound August 1970 ACCEPTED BY THE COUNCIL OF INDUSTRIAL DESIGN FOR INCLUSION IN DESIGN INDEX Metrosound Speaker Systems MODEL HFS 10 10 watts handling capacity 8 ohm impedance Teak finish Size 14 x 9 x 7 As used in the Stereo 10 10 Compact System and available in matched pairs at 26 3 8 MODEL HFS 20 20 watts handling capacity 8 ohm impedance Teak finish Size 23 x 1127 x 103 P
199. e Size 134 lt lljin Above L motor board 3jin below 24in AC 200 250v with STEREO MONO xTAL T Post 5 BSR UA70 Stereo Mono Transcription 14 Auto Changer Calibrated Stylus Pressure BSR Minichanger UABO Stereo Mono Plays 12 10 or 7 records 8 Size 12 x 8jin AC 200 250v Post 5 LIMEN o M oed Los ANC a GARRARD PLAYERS with Sonotone 9TA Cartridges Stereo Diamond Mono fa e SP25 Mk II 15 ATG0 Mk II 215 Model 418 Post 5 REOORD PLAYER PORTABLE CABIN T5 J Space tor amplifler and autoohanger Post 5 RCS DE LUXE 8 WATT AMPLIFIER Ready made with stage triode pentode valve 8 watia output Tone and volume controls Isolated mains transformer knobs loudspeaker valves ECL82 EZ80 Response 50 12 000 4 cps Sensitivity 200mV Post 5 RSC 2 WATT AMPLIFIER with loudspeaker 3 and valves UCL82 and UY85 Post 5 R C 8 TEAKWOOD BASE Ready out out T 6 for mounting State player make and model R C 8 PLASTIC COVERS FOR ABOVE 77 6 BASE Durable tinted plastic attractive a rance EMI PICK UP ARM Complete with mono cartridge 80 EMI JUNIOR 4 SPEED RECORD PLAYER 3 Post Mains operated motor turntable and pick up 5 HI FI PICK UP CARTRIDGES GP94 55 GP93 45 GP91 80 GP67 18 6 ACOS L P only 10 6 All standard fixing complete with stylus CRYSTAL MIKE INSERTS li dia 6 6 ACOS 13 dial 12 6 BM3 1 dia 9 6 PORTABLE AMPLIFIER Portable mini p a system Many uses ideal for
200. e appropriate DORCHESTER Size 16 x 11 x 9in appr Range 45 15 000 c p s Rating 8 10 watts Fitted High flux 13 x 8in 9 Gns Dual Cone speaker Imp 3 or 15 ohms Carr 7 6 STANWAY ll Size 20 x 103 x 94in approx Rating 10 watts Inc 13 x 8in speaker with highly flexible cone surround long throw voice coil and 11 000 line magnet High flux tweeter Handsome Scandinavian design cabinet Range 35 20 000 c p s Imp 15 ohms Gives smooth realistic sound output 7 Gns See top of page for illustration Eee R S C TAIZ MKIII 6 5 65 WATT STEREO AMPLIFIER FULLY TRANSISTORISED SOLID STATE CONSTRUCTION HIGH FIDELITY OUTPUT OF 6 5 WATTS PER CHANNEL Designed for optimum performance with any crystal or ceramic Gram P U cartridge Radio tuner Tape recorder Mic etc X 3 separate switched input sockets on each channel yy Separate Bass and Treble controls 3 Slide Switch for mono use yy Speaker Out put 3 15 ohms y For 200 950v A C mains yy Fre quency Response 20 20 000 c p a 2dB yy Harmonic Distortion 0 3 at 1 000 c p s Hum and Noise 70dB ye Sensitivities 1 50mV 2 400mV 3 100mV Output rating 1 H F M Handsome finish Facia plate and Knobs Complete kit of parts with full wiring diagrama amp instructions Factory built with 12 months guarantee 17 gns or Deposit 28 0 0 and 135Gns 9 mthly pymts 39 Total 20 11 0 Or in Teak or Afrormosia Car 7 9 Total 24 6 0 Super 30 Amplifier 15 15 watt i
201. e moving coll speaker Total building costs 44 6 ss IMPROVED MODEL roamer six SIX WAVEBAND PORTABLE WITH 3in SPEAKER Attractive black case with red grille and cream knobs and dial polished brasa inserts Bize 9 x 54 x 2jin approx Tunable on Medium and Long Waves two Short Waves Trawler Band plus an extra M W band for easier tunIng of Luxembourg etc Sensitive ferrite rod aerial and latest telescopic aerial for Short Waves Improved circult 8 stages 6 tran Bistors and 2 diodes including Micro Alloy R F Transistors etc Carrying strap 2 6 extra Easy build pians and parts price list 2 FREE with parts Total building costs Easy build plans and parts price liat 1 6 FREE with parts 47 6 ue RADIO EXCHANGE CO j 61 HIGH STREET BEDFORD l l enclose ROAMER EIGHT TRANSONA FIVE POCKET FIVE Tel 0234 52367 please send items marked ROAMER SEVEN TRANS EIGHT ROAMER SIX J O Total building costs I I I 7 9 J 6 P amp P 4 6 I Parts price list and plans for l I i i ame N Callers side entrance Stylo Shoe Shop Ades ec es REDE B Open 10 1 2 30 4 30 Mon Fri 9 12 Sat i ret PW 24 l P ee 671 LIFETIME ACHIEVEMENT IN 75 DAYS OPERATING DXCC 100 Countries Worked SWLs THIS ALSO MEANS 100 Countries Heard By G3DCS E H CHAUDRI C ENG F I E R E CHARTERED ENGR USING THE WORLD S MOST VERSA
202. e physical characteristics of the uniquely designed housing In reviewing this exclusive Sinclair design technical journals have been loud in their praise for it and it comfortably stands comparison with very much more expensive loudspeakers The shape of the Q 16 enables it to be positioned and matched to rts environment to much better effect than is the case with conventionally styled enclosures and with its improved styling the 0 16 presents an entirely new and attractive appearance A solid teak surround is used with a special all over cellular black foam front chosen as much for its appearance as for its ability to pass all audio frequencies unimpaired The 0 16 is compact and slim and is the ideal shelf mounted speaker and brings genuine high fidelity within reach of every music lover Specifications Construction A sealed seamless sound or pressure chamber is used with internal baffle all of materials carefully chosen to ensure freedom from spurious tone coloration Loading Upto 14 watts R M S Input impedance 8 ohms Frequency response From 60 to 16 000Hz as confirmed by independently plotted B amp K curve Driver unit Specially designed high compliance unit having massive ceramic magnet of 11 000 gauss aluminium speech coil and special cone suspension Excellent transient res ponse is achieved x Size and styling 9 square on face x 4 deep with neat pedestal base Black all over cellular foam pee Uo fro
203. e specifications of a number of pieces of audio equipment one could be forgiven for concluding that manufacturers set out deliberately to confuse Usually the reason for the great discrepancies is simply that each applies the standard to suit his own test procedures In an effort to clarify matters or at least to present the most important tests and measurements to the audiophile Practical Wireless has whittled away the mass of standards and revealed the bare bones of facts and figures relating to international audio stan dards and has included where such inclusion may help the methods and limits of testing and the types of test gear that must be used There are at least eighteen standards organisations publishing audio specifications Space forbids their being listed here Fuller details including the ad dresses of standards making organisations can be furnished to readers who apply to the Query Service in the usual way PRACTICAL WIRELESS QUERY SERVICE Before using the query service it is important to read the following notes The PW Query Service is designed primarily to answer queries on articles published in the magazine and to deal with problems which cannot easily be solved by reference to standard textbooks in order to prevent unnecessary disappointment prospective users of the service should note that a We cannot undertake to design equipment or tosupply wiring diagrams or circuits to individual requirement
204. e to master all this n p n and p np business and zeners and all the other mysterious things happening today in the world of radio So please tell those size 8 heads to have pity on us old ones we can t help it we were just born 60 years too soon W Wickins Norfolk 633 Equalisers amp Mixers NTEGRATED circuit flatpacks are now available containing two or more linear amplifiers with MOTOROLA MC1303P sufficient isolation for multi channel audio use Summary of Characteristics Possible applications are in equalisers for stereo Type Monolithic two channe amplifier silicon signal sources where two preamps with identical epitaxial structure in standard 14 lead flatpack frequency responses are required and in audio mixers Max supply voltage 28 C 15 0 18V d c where two or more preamp stages are needed two Temperature range 9 75 C for each signal source for stereo Each of the suis separation 10kHz gt 60dB Spr des j aracteristics each channel circuits described here consists of one i c and a few Open loop gain gt 8000 78dB discrete components and can be constructed inside a Output voltage swing 4 5 5 5V r m s max very small space for example the equaliser circuits Input noise volts 0 5zV typical can be fitted easily into a matchbox More space is Input bias current mean of occupied by the controls in the case of the mixers ve amp ve inputs 1 104 A Power requirements are small and are sim
205. ections are common to both channels From the character istics listed in Table 1 it can be seen that the channel separation is high The circuit consists of 16 trans istors and 18 resistors not an exceptionally large total to squeeze on a tiny silicon chip inside a plastic slab only tin long by today s standards Component references are given for the left channel only as both amplifiers are identical Operation is as follows Positive and inverted inputs are received by the long tailed pair amplifier Tri Tr2 This is directly coupled to a second similar amplifier Tr4 Tr5 The tail current of Tr4 Tr5 is sampled by Tr3 which is a constant current source in the tail of Trl Tr2 This 634 Fig 1 The internal circuitry and packaging of the MC1308P i c two channel amplifier od UNE This c ntains the iran fitted with a interchangeable spare bits 35 and 37 resin cored solder felt cleaning pad stand for soldering iron and a booklet How to solder From Electrical and Radio Shops or s nd cash to Antex Model CN 240 2 15 watts 240 volts 34 Fitted with nickel plated bit 34 and in handy transparent pack From Electr cal and Radio Shops or send cash to Antex ord 3 1 PWi2 635 R ROC ELECTRONICS 50 PROJECT ELECTRONIC KIT Model R 130 King of the Roc Electronic Kits is the Giant R 130 which makes up into no less than 50 separate projects including Radio Receivers Frans
206. ectly adequate if low efficiency high quality loud speakers are used the PZ 6 stabilised power supply unit will be used The PZ 8 will be needed with Z 50s which can be used for any Project 60 system Project 60 modules incorporate some of the most advanced cireuitry in the world to achieve unsurpassed standards of high fidelity and modern manufacturing techniques enable these modules to be sold at exceptionally attractive prices Assembling the modules requires no skill or previous experience since the manual supplied with the modules explains clearly how everything can be done with nothing more than the simplest of domestic tools Project 60 manuals How to assemble and use Project 60 modules to best advantage in the above and other applications will be found in the fully descriptive Project 60 manual included with Project 60 systems This 48 page manual is available separately price 2 6d including postage System The Units to use In conjuction with Costof Units Project 60 tuner A Car Radio 2 30 Existing car radio Sinclair 89 6 Micromatic B Simple battery powered 2 30 Crystal pick up 12V or more 89 6 record player battery supply and volume control C Mains powered record player Z 30 and PZ 5 Crystal or ceramic P U 9 9 0 34 9 0 Volume control etc D 20 20 watts R M S stereo Two Z 30s Stereo 60 Crystal ceramic or magnetic 23 18 0 48 18 0 amplifier for most needs and PZ 5 P U most dynamic speaker
207. ed and checked 110 250v A C 65 Carr 2 MODEL 8 260 MODEL 260 B General Purpose Panel Mounting Bench Mounting i Amp 5 10 0 1 Amp 5100 5 Amp 451 Please add postage 2 5 Amp 6 15 0 5 Amp 9 15 0 ALL MODELS INPUT 230 VOLTS 8 Amp 21410 0 50 60 CYCLES 10 Amp 18 10 0 OUTPUT VARIABLE 12 Amp 221 0 0 0 280 VOLTS 20 Amp 87 0 0 Special discounts for quantity UNR 30 RECEIVER 4 Bands covering 550ke s 30mc s B F O Built in Speaker 220 240v A C Brand new with instructions 18 18 0 Carr 7 6 WS62 TRANCEIVERS Large quantity available tor EXPORT Excellent condition Enquiries invited UR 1A SOLID STATE COMMUNICATION RECEIVER 4 Bands covering 550kc s 30mc s FET S8 Meter Variable BFO for 88B Built In Speaker Telescopic Aerial Bandspread Sensitivity Control 220 240v A C or 12v D C 191 x 41 x 7 Brand new with instructions 24 Carr 7 6 FULL RANGE OF CODAR AMATEUR EQUIPMENT IN STOCK LAFAYETTE LA 324 STEREO AMPLIFIER Solid State 12 5w rma per channel 20 20 000 Hz 1db Inputs Mag Cer Tuner Aux Output 4 16 Headphone Socket Tape Out put Black and Brushed Aluminium Front Panel 103 x 34 x 81 24 Carr 7 6 FULL RANGE OF PARTRIDGE JOYSTICK AERIALS IN STOCK TRIO 9R59DE COMMUNICATION RECEIVER 4 bands 500kc s 30mc s 8 Meter Variable B F O Bandspread 7 x 15 x 10 115
208. ed as it sounds most perplexing to your caller There is less danger of feedback if the pickup is attached to the telephone earpiece the stray field is not very strong here but there is the advantage that less of one s own speech is amplified The best position for the pickup will be found slightly off the axis of the earpiece other uses The pickup is extremely sensitive to any alternating magnetic field it will pick up hum anywhere near a mains transformer and will actually reproduce the signal from a radio if placed near the voice coil of the radio loudspeaker or near the output trans former Also both field buzz and line whistle can be detected near a television set The unit can also be used for experiments in communication over short distances by magnetic field As a starter if about 12 yards of single core wire is laid under a carpet in a large coil of about 6 turns and the ends of the wire connected to the loudspeaker output of an amplifier or radio the telephone amplifier will pick up the signal several feet away from the coil This is one form of wireless communication for which no licence is required Without the telephone pickup the unit is an extremely sensitive amplifier plus speaker combina tion with a multitude of uses It can be connected to any low level audio source such as a radio tuner microphone record cartridge tape playback head or electric guitar as long as hi fi quality is not expected
209. ed dis leriminator Ample output to feed most amplifiers Operates on 9 V battery Coverage 88 108Mo s Ready built ready for use Fan tastic value for money 6 P amp P 2 6 Stereo multiplex adaptors Latest Catalogue Our latest edition giving full details comprehensive range of HI FI EQUIP MENT COMPONENTS TEST EQUIP MENT and COMMUNICATIONS EQUIP MENT FREE DISCOUNT COUPONS VALUE 10 248 pages fully illustrated ana detailing thousands of items at bergain prices con woofer SEND NOW Mi Fidelity e ru ONLY Ex 7 6 P amp P 1 6 See opposite page gt RUSSIAN C1 16 DOUBLE BEAM OSCILLOSCOPES 5 MHz Pass Band Separate Yl Y2 ampli fers Calibrated triggered sweep from 2 sec to 100 milli Bec cm Supplied complete with all accessories and instructions 87 Carr paid MARCONI T 44 1956 AF Absorption Wattmeter 1 pjwatt to 6 watts 20 Carr 10j TEM I DECADE RESISTANCE ATTENUATOR Variable range 0 111dB Connections Unbalanced T and Bridge T Impedance 600Q range 0 1dB x 10 1dB x 10 10 20 30 40dB Frequency d c to 200kHz 3dB Accur acy 0 05dB FIndication dB x 0 01 Maximum input lees than 4W 50V Built in 600 Q load resistance with Internal external switch Brand new 427 10 0 P amp P 5 BELCO AF 5A SOLID STATE SINE SQUARE WAVE C R OSCILLATOR fine 18 200 000 Hz Square 18 50 000 Hz Output max 10 dB 10
210. ed in a solid plastic package which holds the metal heat sink and connecting pins This exciting device ts not only more rugged and reliable than any previous amplifier it also has considerable performance advantages The most important are complete freedom from thermal runaway due to the close thermal coupling between the output transistors and the bias diodes and very low level of distortion The IC 10 is primarily intended as a full performance high fidelity power and pre amplifier for which application it only requires the addition of such com ponents as tone and volume controls and a battery or mains power supply However itis so designed that it may be used simply in many other applications including car radios electronic organs servo amplifiers it is d c coupled throughout etc Once proven the circuits can be produced with complete uniformity which enables us to give a full guarantee on every IC 10 knowing that every unit will work as perfectly as the original and do so for a lifetime 59 6 SINCLAIR C 1 with IC 10 manual Post free Road Cambridge iri leuir Q 16 High fidelity loudspeaker Developed out of the revolutionary and much praised design of the original Sinclair Q 14 comes this more advanced version to meet the requirements of even greater numbers of high fidelity enthusiasts The Q 16 employs the same well proven acoustic principles in which a special driver assembly is meticulously matched to th
211. ed with product pictures aud technical diagrams 2 post free Add 4 if required to be sent o seas by air mail Dept PW 12 28 ST JUDES ROAD ENGLEFIELD GREEN EGHAM SURREY Hours 9 5 30 Sat 1 p m Tel Egham 5533 STD 0784 3 Telex 264475 613 TV eS FECT TRANSISTO wi Mp FER 7 UE ruo PET Mkl 145 plus 7 6 p amp p Specification Output per channel 10 watts r m s Frequency bandwidth 20 Hz to 20 kHz 1db at 1 watt Total distortion at 1 kHz at 9 watts 0 5 Input sensitivities CER P U 100mV into 3 meg ohms Tuner 100mV into 100K ohms Tape 100mV into 100K ohms Overload Factor Better than 26db The 29 10 0 Stereo system The Duetto is a good quality stereo amplifier attractively styled and finished It gives superb reproduction previously associated with amplifiers costing far more SPECIFICATION R M S power output 3 watts per channel into 10 ohms speakers INPUT SENSITIVITY Suitable for medium or high output crystal cart ridges and tuners Cross talk better than 30dB at 1Kc s RADIO amp TV COMPONENTS Acton Lid 21c High Street Acton London W 3 6NG Also at 323 Edgware Road London W 2 ALL ORDERS BY POST TO OUR ACTON BRANCH Terms C W O All enquiries S A E This superb stereo system is a real price break through It comprises the VISCOUNT F E T Mk amplifier on which full details are given below the famous Garrard SP 25 including teak veneer base
212. edge I have needed AE Onst B SIgDature iets sstete aaan T Rd MN CM nci deeem T 1f under 21 signature required of arent or guardian 75 UNDERSTAND THE BASIC FACTS a This is the first time I have been able to understand the basic facts as all other books are too complicated L W Sheffield A TECH PRESS PUBLICATION POST NOW FOR THIS OFFER I 612 BLOCK L FULL POSTAL ADDRESS tti ELECTROVALUE EVERYTHING BRAND NEW amp TO SPEC e LARGE STOCKS e NO SURPLUS PEAK SOUND PRODUCTS ENGLEFIELD CABINET KITS Build it 12 12 or 25 2 BARGAINS IN NEW SEMICONDUCTORS ail power types supplied with free insulating sets MANY ITEMS AT NEW REDUCED PRICES 1N914 1 8 2N3706 1N3154 ale 2N3707 1N4148 2N3708 1N5054 shane 18940 2N3711 2N696 2N3731 2N697 2N3794 2N706 2N3819 2N1131 2N3820 2N1132 2N3904 2N1302 2N3906 2N1303 2N4058 92NI304 2N4059 2N1305 2N4080 2N1613 2N4061 2N1711 2N4062 2N2147 2N2218 2N2270 2N 483 2N9 484 2N2646 2N2904 2N2974 2N2925 2N 2926 2N3053 2N3054 2N3055 2N3325 2N3663 2N3702 2N3703 2N3704 2N3705 RESISTORS Code Power 1 20W 40512 40602 AULO7 AC126 ACI 7 ACI28 ACI76 ACY ACY40 ACYA4L AD142 AD149 AF114 AF115 AFII6 AF117 AF124 AF127 AF139 AF180 AF239 ABY26 ASY27 ASY23 B5041 hAtQ02 BA166 BA130 BA156 BC107 BC108 BC109 BC125 BC126 2N 4289 2N4291 2N 4292 2N4410 2N5062 2N5163 2N5192 2N5195 2N5457 2N5458 2N5459 4
213. edium waveband supersensitive tuning control and variable volume control Ideal for outdoors and indoors ONLY 4210 19 60 P amp P 4 6 p 600 WATT LIGHT DIMMER SWITCH Same size ag standard wall switch and will dim incandescent lighting from full on to off Heavy plastic box with control knob LIND AIR PRICE 410 0 P amp P 3 6 UNIL EX Audio Modules Now you can build your own stereo units as you want them and entirely in your own home A good quality stereo amplifier can be built with no electrical knowledge All solid state Baxendall tone control circuit no soldering terminal block connections throughout Everything you need to know about UNILEX SYSTEMS is In the Mullard book Do it yourself stereo Superb de signs detailed plans simple instructions in non technical language covering 4 systems in 4 price ranges Send for your copy now 5 Post Free UNILEX Audio Modules Amplifier Module EP9000 2 18 0 each Pre Amplifier Module EP9001 Power Supply Module EP9002 4 12 Control Panel Asrembly and scutcheon Plate 3 5 0 BUILD A STEREO AMPLIFIER FOR ONLY 16 15 0 P amp P 7 6 Do it vourself teres 9000 1 3 20 UNILEX PACKAGE DEALS Unilex Modules 116 15 0 Unilex Modules 416 15 Garrard 2025 211141 Garrard 8P25 Mk II 15 11 4 Celestion Bpeakera 5 17 0 B 8 R Cl Cartridge 3 17 8 A Celestion Speakers 5 17 0 34 6 1 28 gns F2 LIND AIR LIN
214. efore essential to feed the first two stages with well decoupled h t or motor boating oscillation will be caused by the signal appearing across the internal impedance of the battery By using a fairly high value for RIO which drops over 20 of the supply voltage a reasonably small capacitor can be used for C9 while maintaining an adequately large C9 times R10 value construction The circuit lends itself to miniaturization as all the components are readily and cheaply available in miniature form The prototype unit was built into a identification Lead icku p h P Tr1 Tr2 2N2926y or g 2N2926y org components list Resistors R1 180k Q R6 29kQ R2 22kQ R7 15kQ R3 15kQ R8 22kQ R4 29kQ R9 100kO R5 180kQ Ri0 33kQ All resistors 10 1 watt types VR1 5k miniature radio edgewise volume con trol with switch VR2 100k 2 subminiature skeleton preset pot Capacitors C1 8uF 3V electrolytic C2 100pF ceramic C3 8 4F 3V electrolytic C4 8uF 3V electrolytic C5 100pF ceramic C6 8uF 3V electrolytic C7 not used C8 not used C9 1004F 64V seetext C10 8uF 3V electrolytic C11 200uF 6V electrolytic Semiconductors Tr1 2N2926Y or G Tr2 2N2926Y or G LC PA234 General Electric Miscellaneous Telephone pickup coil 3 5mm miniature jack Socket 2in diameter loudspeaker 15 3 9V battery PP3 Veroboard approx 21 x 2in 0 15in matrix Soap box battery ctips etc Available from Chiltmead L
215. ely road signs I do not know if he drives a car but if he does although traffic sig nals can be recognised by posi tion what of the single lamps used at traffic control of road works and the very many danger signs and direction signs Also what about the compulsory red rear lights on cars Although we now have to accept the new colours for mains wiring I still cannot see the reason for the modification or for the choice of these colours Often I feel they get together and decide on some new way or new regulation particularly on cars to boost sales and profits E W Baigent Buckingham shire Printed circuits I read Mr R A Yates article in the May edition of Practical Wireless concerning the making of printed circuit boards with some interest However Mr Yates advice to bend the ends of the leads to the wire becom ing bonded to the copper lami nate with a film of solder which does not remove easily on de soldering and removal of the component becomes more diffi cult and can result in a damaged laminate The method taught me is to leave the leads long and to push the leads through the holes drilled in the board as in Fig 1 The iron is then rested with the side of the bit on the laminate and the end on the lead A quick application of the solder results in a neat mound of solder as in Fig 2 It only remains then to cut off the lead at the top of the mound giving the re
216. ency ceramic magnets Treated Cone ON surround D indicates Tweeter Cone providing ex r tended frequency range up to 15 000 c p s A for Record Playing units cut for Garrard 1025 2025 3000 A T60 Impedance 3 or 8 15 ohrna Please state choice HF102D 10 10W 67 11 HF126 12 15W 25 5 0 veneer finish Modern design Acoustically lined pleasing resulta with any 8in Hi Fi speaker 8E10 For outstanding results SEl2 For excint prfmnce with 12in RECORD PLAYING UNITS RS C PLINTHS pareut plastic cover Ready to RP2C Garrard SP 5 Mk H SP25 etc Pliance ceramic Stereo Mono cart Exceptional performance at low coat HF801D 8 8W 54 8 HF120D 12 15W 89 9 HF120 12 15W 79 8 HF126D 12 15W 515 0 HI FI SPEAKER ENCLOSURES peas or Atrormosn p All sizes approx Carr 5 per enclosure JEB Size 16 x Il x Yin Pressurised Giver 4 14 6 BES For optimum performance with any 8in Hi Fl speaker Size 22 x 16 x 9in Ported 5 15 0 with loin Hi Fi spkr Hi Fi speaker and Tweeter Bize 24x15x10in P td 9 19 9 Size 25 x 16 x 101in 6 19 9 Superior Solid Natural Money saving unita Mounted ioi on Plinth Supplied with trans Wood construction plug mto Amplifier or Tape recorder with heavy turntable fitted Goldring C890 high com ridge with diamond lus Carr 9 6 24 12 6 ABLE WITH TRANSPARENT gns PLASTIC COVER Carr Free LEADING MAKES HI FI EQUIPMENT at CLEARANCE PRICES Available at branches oniy
217. er 67 6 LASTIC METERS Type MR 38P 1 2 Sait unre fronts 35 27 6 Type MR 62P 23in square fronts 62 40 52 40 52 40j 47 6 40 45 40 40 40 40j B Meter 1mA 49 40 VU Meter 62 40 1 amp A C 49 40 5 amp A C 40 40 10 amp A C 40 40 20 amp A C 40 40 30 amp A C 40 Type MR 65P jin x 34in fronte 42j 42j 42 4g 42 42 42 49j 42 42 S MeterlmA 47 6 VU meter 67 6 5OmA A C 4 42 100mA A C 200mA A C 500mA A C lamp A C 5 amp A C 10 amp A C 42 20 amp A C 30 amp A MARCONI TF885 VIDEO OSCILLATORS 0 6 me s Sine Square Wave 246 Carr 20 MOVING IRON ALL OTHERS MOVING COIL Please add postage j S Meter IMA 37 6 VU meter 45 lamp A C 30 Samp A C 80 10 amp A C 80j 20 amp A C 80 30 amp A C 30 SEW BAKELITE PANEL METERS Type MR 05 sin sanare fronts 500m 85 85 35 35 86 85 85 35 35 10 amp A C 20 amp A C 30 amp A C 50 amp A C VU meter EDGWISE METERS Type PE 70 E 17 82in x 1 15 82in x j in deep BOLA 60 500A 59 NOUS Ho ImA 47 6 M douA See 300V AG 47 6 200A 55 VU meter 65 SEND FOR ILLUSTRATED BROCHURE ON SEW PANEL METERS DIS
218. er aux CE 20 Carr 7 6 AMERICAN TAPE First grade quality American tapes Brand new Discount on quantities Sin 225ft L P acetate Shin 600ft T P mylar Din 600ft std plastic bin 900ft L P acetate Bin 1 200ft D P mylar 15j Shin 1 2001t L P acetate 12 6 5 in 1 200ft L P mylar 16 5iin 1 800ft D P mylar 22 6 Blin 2 400ft T P mylar 89 6 Tin 1 200ft std acetate 12 6 Tin 1 800ft L P acetate 158 Jin 1 800ft L P mylar e BO Tin 2 400ft D P mylar 25 7in 600ft T P mylar AB Postage 2j Over 3 post paid e OUR 3 Carr SINCLAIR EQUIPMENT Project 60 Package offers 2 x Z30 amplifier stereo 60 pre amp PZ5 power supply 819 0 0 Carr 7 6 Orwith PZ6 power supply 21 Carr 7 6 2 x Z60 amplifier stereo 60 preamp PZ8 power supply 21 10 0 Carr 7 6 Transformer for PZ8 59 6 extra Add to any of the above 4 17 6 for active filter unit and 16 for a pair of Q16 speakers All other Sinclair products in stock 2 000 amplifier 23 Carr 7 6 Neoteric amplifier 46 Carr 7 8 HOSIDEN DHO4S 2 WAY STEREO HEADSETS Each headphone tains a jin and jin tweeter Bulit in individual level controls 8Q imp 25 18 000c s with cable and stereo plug 5 19 6 P amp P 2 6 TRANSISTORISED FM TUNER TRANSISTOR HIGH QUALITY TUNEE SIZE ONLY 6x4x2jin 3 I F stages Double tun
219. er by the heat sink tab This way of mounting was thought more elegant even though there is no indication that the i c needs the extra heatsink thereby obtained By choosing the smallest type of skeleton preset for VR2 it is possible to mount this component directly onto the i c pins Capacitor C11 is the only remaining component and this is wired directly from the i c to the speaker A piece of plastic insulating tape prevents any of the Veroboard conductors shorting against the speaker frame The only wires which have to be kept short are those from the input socket to the Veroboard These should be tightly twisted If with some other layout more than an inch or so length is required a small screened cable should be used with the screen connected to the earth side The space occupied by the socket can be reduced if necessary by breaking off the shorting contact which is not needed After checking the wiring with special attention to the lead connections of transistors electrolytics and the i c and to possible shorts between Vero board conductors caused by stray solder blobs switch on Check that the voltage at pin 12 of the i c can be varied by VR2 and set it to half the supply voltage The unit should produce some hiss at 650 battery A AS te AA APA Ss eee T TOO ve Fig 2 The component layout The heat sink tab of the i c is soldered to the magnet of the loudspeaker full volume If not c
220. er than 60dB Translators 4 silicon Planar SPEAKERS Size 20 x 20 x 10 incorporating Baker s 12 heavy type and 3 Germanium type Maina input 220 250V A C Size of chassis l0iIn x duty 25 watt high flux quality loudspeaker with cast frame Cabinets attractively finished in two tone colour scheme Black and grey COMPLETE SYSTEM 4 5 Plus Sound 50 amp and 2 speakers P amp P 4iin x 2iin For use with Std or L P records musical instruments all makes of pick ups and mikes Separat te basa and treble lift control Two inputs with control from and mike Built and tested gram RELIANT Mk Il in siwulated teak case 7 5 plus 7 6 P amp P THE DUO SPEAKER SYSTEM Similar in design to those on the previous page the 2 way speaker system is beautifully finished in polished teak veneer with matching vynair grille It is ideal for wall or shelf mounting either apright or horizontally Type 1 BPECIFICATION Amplifier 28 10 0 plus 20 P amp P Impedance 3 8 or 10 ohms please state requirement It incorporates Goodmans high flux 6in x din speaker and 21in speaker Teak finish 12in x 62in x 51in 4 guineas Speakers 12 10 0 each plus 30 P amp P Bux Oln x din ape LIQUIDATED STOCK DANSEITE TOURISTE MK3 p B CAR RADIO rJ pe pum mum HIE ALL TRANSISTOR N i Wer b p e_r 1 1 1 LIA Beautifully designed to blend with the interiors of all cars Permeability tuning and long w
221. ereas this is acceptable on larger speakers it will cause intolerable distortion in smaller types The power supply is nominal 12V and the internal impedance of this will usually mean that no decoupling is needed however if stability problems arise a 250uF 16V capacitor connected across the two supply rails will probably cure this CONSTRUCTION As the loudspeaker has to be fairly large it will be difficult to build a handheld unit and in any case it is far simpler to build the amplifier into the loud speaker cabinet Tr3 must be heat sinked VR2 requires setting only once before switching on set it to minimum resistance so Tr3 base and emitter are shorted and after applying the supply current increase this slowly until signals are relatively undistorted increasing beyond this point will only raise the quiescent current In the region of high quiescent current the quality is good but Tr3 will become very hot and may blow so care should be taken with the setting MAKE 5 DIFFERENT REAL WORKING ELECTRONIC ORGAN TRANSISTOR RADIOS Last 250 TOTAL BUILDING 39 6 PRICE Amazing Radio Construction set Become a radio expertfor 39 6 A complete Home Radio Course No experience needed Parts including simple instructions for each design Illustrated Don t confuse with ordinary electric organs that simply blow air over mouth organ type reeds etc Hight months were spent in creating and testing this superb revolutionary electronic
222. erride switch enables you to switch from one track to the next at the push of a button at the same time a numbered indicator lights up to show which track is playing Beautifully finished in an oiled walnut cabinet the R 133 is mechanically engineered to provide long and reliable service SPECIFICATION Tape speed 9 5 em sec 32 i p s Wow amp flutter better than 0 3 Frequency range 40 12 000Hz Cross talk better than 45dB at 1 000Hz Output 5W total 2 5W per channel Amplifier outputs 200mV EXECUSA PRICE 36 0 0 STEREO HEADPHONES Model R 328 Built up to a standard not down to a price the R 328 stereo headphones represent a breakthrough in value for money A valuable addition to any stereo installation they will provide many hours of listening pleasure SPECIFICATION Matching impedance 8 16 ohms Frequency range 30 15 000Hz PRICE 2 8 0 636 This excellent transistorised battery operated kit will not only provide hours of entertainment when made up but aleo in ita construction It receives the normal broadcast band 550 KhZ l 6MhZ and on shortwave 1 5 MhZ 30 MhZ in three bande The 32 page manual not only shows step by step instructions on how to assemble the kit but also includes a guide on broadcasting stations through out the world 4 BAND SHORT WAVE RECEIVER KIT Mod R 140 PRICE 9 8 0 PROFESSIONAL SOLID STATE FOUR BAND COMMUNICATION RECEIVER This is
223. essfu Jeompietion of course Age 21 1 023 per annum 22 1 087 od 23 1 150 io 24 1 214 25 highest age point 1 288 then by 6 annual increments to amp maixmum of 1 749 per annum Exceilent conditions and good prospects of promotion Opportunities for service abroad Applicants must be United Kingdom residents normally under 35 years of age at start of training course and must have at least 2 years operating experience cr PMG qualifications Preference given to those who also have GCE O level or similar qualification Interviews will be arranged throughout 1971 Application forms and further particulars from RECRUITMENT OFFICER TRO 3 Government Communications Headquarters Oakley Priors Road CHELTENHAM Glos GL525AJ Tel No Cheltenham 21491 Ex t 2270 SERVICE SHEETS SERVICE SHEETS Radio TV etc 8 000 models List 2 S A E enquiries TEL RAY 11 Maudland Bank Preston RADIO TELEVISION over 3 000 models JOHN GILBERT TELEVISION 1b Shep herds Bush Rd London W 6 SHE 8441 LARGE SUPPLIER OF SERVICE SHEETS T V RADIO TAPE RECORDERS RECORD PLAYERS TRANSISTORS STEREOGRAMS RADIOGRAMS CAR RADIOS Only 5 each Manuals from 10 j plus large S A E Uncrossed P O s please original returned if service sheets not available C CARANNA 71 BEAUFORT PARK LONDON N W 11 We have the largest supplies of Service Sheets strictly by return
224. etting up this circuit first remove the h t from the p a stage and provide drive at 7MHz to the grid of the multiplier stage and tune the output circuit to 14MHz for maximum grid current to the p a stage Check by means of a calibrated absorption wavemeter that the correct harmonic has been chosen Now remove turns from the inductor L one at a time until the circuit resonates at 14MHz with the capacitor almost at maximum If L is fitted with a dust core it may be possible to reach this con dition by simply adjusting the core Now reduce the capacitance until another peak in grid current is found which should correspond to the third harmonic on 21 MHz but check again with the wavemeter Reduce the capacitance still further when the fourth harmonic on 28MHz should appear with the capacitor at almost minimum capacitance Check again with the wavemeter If difficulty is experienced in reaching or covering all the 10 metre band check the circuitry for stray capacitances such as those due to the tuned circuit wiring not being the shortest possible or being too close to earthed objects The valveholder should be of ceramic or similar low loss material The drive will fall off with increasing frequency but it should still be possible to get sufficient drive to permit the p a to be driven to a reasonable input on 10 metres Twenty five watts input is better than no input at all If operation on 40 metres is con templated and the author thor
225. evel of distortion than any other tuner we know Stereo broadcasts are received automatically as the tumng control 1s rotated a panel indicator lighting up as the stereo signal is tuned in Atthough the tuner iS intended primarily for use with a Project 60 system it can be used to advantage with any other high fidelity system It is easily mounted into any cabinet as shown in the manual supplied with it Specifications Number of transistors 16 plus 20 inl C Tuning range 87 5 to 108 MHz Capture ratio 1 5dB Sensitivity 2uV for 30dB quieting 7yV for full imiting Squelch level 200V A F C range 200 KHz Signal to noise ratio gt 65dB Audio frequency response 10Hz 15kHz x1dB Total harmonic distortion 0 15 for 3096 modulation Stereo decoder operating level 2uV Pilot tone suppression 30dB Cross talk 40dB I F frequency 10 7 MHz Output voltage 2x 150mV R M S Aerial Impedance 75 Ohms Indicators Mains on Stereo on tuning indicator Operating voltage 25 30 VDC Size 3 6x1 6x8 15inches 91 5x 40x 207 mm Wer NAME ADDRESS Sinclair IC 10 the world s most advanced high fidelity amplifier Specifications Output 10 Watts peak 5 Watts RM S con tinuous Frequency response 5 Hz to 100 KHz 1dB Total harmonic distortion Less than 1 at full output Load impedance 3 to 15 ohms Power gain 110dB 100 000 000 000 times total Supply voltage 8 to 18 volts Size 1x04x02 inches Sensitivity 5mV Input impeda
226. f August We were there lad we were there One of the structures that the wild wind uprooted must have been the local radio mast for Henry s holiday punishment has been to maintain a radio silence Despite Mrs H and her femi nine tendency to bring along half the domestic equipage we have landed in an alien world that appears not to believe in com munications There is no radio in the hotel bedrooms and a portable wireless set is the one amenity we did not bring Musak there is true burbling away in its sugary fashion in the unreachable corners of lounge dining room and hallway Tele vision there is with a picture that leaves too much to be desired The mountains breed telegenic ghosts that make all programmes more interesting than informative if you happen to have a taste for surrealism But no wireless It could be argued that Top of the Pops would sound sacri legious in such surroundings Perhaps the rural bumblings of Walter Gabriel could be tolerated but we cannot even get that Gasping for news we tried the car radio We were even pre pared to put up with Tony Bran don But we then found the answer to the wireless less com munity those dratted mountains no less Reception varies between the impossible and the outlandish HENRY No 74 In the Wilds Gleefully skinning a heretic You should worry down there in Centralshire about the vestige of a 19kHz beat Up here if
227. f the circuit in Fig 1 will show that it is basically a mating together of two pre viously published circuits the Gramophone Amplifier and last month s General Purpose Preamplifier there are some minor differences but the basic circuit is the same The amplifier produces an output in the order of 1 watt quite adequate for a megaphone Megaphones or loudhailers as they are often called are designed so that both high and low frequencies are not only unnecessary but actually undesirable The microphone used is one of the balanced armature earpieces that we used in our intercom circuit some time ago These used to be used in military telephones and are not only very sensitive and cheap but have an ideal frequency response for our requirements here Since there is little bass content in the voice and little output from the microphone in this region a high value coupling capacitor is unnecessary a 0 5F one was used in the prototype low value electrolytics 1 amp F to 54F are however much smaller physically and cheaper and they could be used instead In this case the negative connection would go to the microphone One of the problems in building a megaphone is acoustic feedback that is the sounds of the loud speaker getting back into the microphone and causing a howl round This problem can be reduced by attenuating the upper frequencies and C2 connected between the base of Trl and the negative line achieves this R1 provides
228. for a bass guitar May and July 1966 J Miller 10 Cortina Avenue High Barnes Sunderland Co Durham dune 1969 issue of P W 4A D Beales 45 Railway Street Southport Lancs November 1967 issue of P E containing fuzz box article John 23 Manor Park Crescent Edgware Middx copy of P E for May 1967 P W for July 1969 and P TV for June 1962 J Glavin North Lodge Northlands Saithilt Chichester Sussex issue of P W containing 7MHz Transceiver articie A Sutton 11 Bennett Grove Lewisham London S E 13 April May June duly August and October 1968 and February April May and June 1969 issues of P W H Lewis c o 18 Vickers Street Motherwell Lanark shire Scotiand issues of P W containing articles on mods for No 62 Mk 2 transceiver Wim Kloosterman P O Box 203 Penrith N S W 2750 Australia January 1987 issue and all other issues of 1967 containing details of the Explorer R L J Winston 82 Stephen s Firs Mortimer Reading RG7 3UY March 1965 issue of P W containing details of the key mechanism of the Solo Organ R J Perry 42 Kirkstall Mount Leeds 5 LS5 3DP Yorks ou March 1969 issue of P W H E Dunsford 10 Mounts Bay Road Penzance ornwall e issues of P W containing articles on the Pedal Steel Guitar T J Woods 16 Bermuda Terrace Deepcut Camberley Surrey December 1989 issue of P W dealing with the Noise Limiter a
229. g in a manner determined by the modulating waveform as a result only brief inter vals are available for frequency determination and the more complex the modulation the briefer the intervals and therefore the greater the possible deviation from the precise frequency This deviation takes the name bandwidth and it evidently applies as much to amplitude modulated signals as to f m transmissions Those parts of the signal lying at frequencies other than the precise carrier frequency are referred to as the sidebands of the signal Now as it is the modulation which is responsible for producing the sidebands it follows that the information can be reconstituted from the sidebands and the carrier may be regarded simply as a means of locating them Therefore to transmit a given amount of information with the minimum radiated power the carrier frequency should be omitted and in a balanced circuit this is precisely the function the i c performs _ Moreover as the sidebands are present symmet rically on each side of the carrier either one carries the full information so for even more effective use of available power and to limit the bandwidth demands even further one of the sidebands may be filtered out The transmitted signal finally produced is referred to as single sideband suppressed carrier or s s b Sideband rejection of course is carried out by a series of LC circuits not in the balanced modulator It should be noted th
230. g nut on bottom section 8 section 54 294 1 d a 12 6 10 section 73 561 3 dia 15 9 All are strongly plated P P amp I on all above up to three 1 SWITCHES Standard toggle metal 250V 2A One hole fixing SPST 2 8 SPDT 2 9 DPST 3 9 DPDT 3 6 Slide type Sub niin DPDT 1 6 each Small DPDT 3 way centre off 1 8 Reed magnetic on off 1 9 up to three 1 1d each all additional Rotary Switches etc in list Example 4 pole 3 way 3 9 1 VIBRATORS 12v 4 pin non synch 14 x 3 3 EXCL PINS 4 6 Genuine PLESSEY 12v 4 pin non synch heavy duty type 121 HD4 17 x 23 EXCL PINS 8 6 12v 7 pin synch type 128R7 12 8 6v 7 pin type GSR7 12 6 All types 1 per vibrator a few other types in our list MAINS NEON TESTER Fly leads 2 Pocket screwdriver type 8 8 1 CONNECTING WIRE Packets of 5 coils asstd cols each coil 5 yds Solid Core 2 9 1 Flexible 8 8 1 3 Super thin for transistor wiring etc 3 3 1 PICK UP WIRE Twin Super thin Flex Screened Sheathed 1 8 yd 6d up to 6 yds over 6 yds post free TWIN MIKE CABLE 1 6 yd SINGLE MIKE CABLE 9d yd Both flexible screened and sheathed Up to 3 yds 8d each additional yard id extra RETRACTABLE FLEXIBLE LEADS Space saving Curly many uses in car and home with phono plug each end 6ft 4 6 12tt 7 9 With phono plug one end phono socket at other 6ft 5 12ft 8 8 1 each all types CURRENT LIST With full ra
231. h connecting cables and plugs The two screened leads between the PA25 modules and the power supply are dis connected from the plugs on the power supply itself These are now taken to VR4 for the right and left hand channels respectively as in Fig 12 The remaining connection is that of the positive supply line for the pre amplifiers This picks up the 35V rail from the right hand channel PA25 module input plug as shown in Fig 12 The negative supply line is obtained by contact between the power unit case and the main chassis Mains neon pilot New wiring Join and tape Red 120 10 O 120 110 O Mains input MU442 power supply Disconnected from MU 442 plugs To power w unit Screened To VR4 B slider An outline of the rear of the MUA442 power Supply 35 to36v supply is also shown in a Signal to R35 on RH Fig 12 Note that the DIN channel input signal input socket is not pre amplifier used as the signal inputs i modules as pogre to the PA25 modules have LH channel power module Din signal input not used O amp Q Fuse Fuse Speaker connections A Mains input 6 Loudspeaker LH channel Loudspeaker RH channel 656 positioned on been chassis re routed to the volume controls VR4 The loudspeaker sockets are also DIN type and the connections are as shown Do not earth the loud speakers at any point and do no
232. he January issue we shall be presenting free the second wall chart on AUDIO STAN DARDS A must for all hi fi enthusiasts PW STEREO TAPE RECORDER A project that has been specifically designed with the constructor in mind the PW Stereo Tape Recorder can be used with almost any tape deck which can be fitted with the specified Marriott tape heads The prototype is based on the R T C 249 push button three speed deck Careful thought has been given to both the electronic and constructional design to make it possible for the recorder to be built by the comparative newcomer to electronic construc tion Simple switching has been made possible by using an unusual equalisation principle and although 16 transistors are used the cost of the complete project should be only around 30 LUXEMBOURG BANDSPREAD POCKET 7 This compact seven transistor superhet radio in addition to covering the full medium wave band has a second band from 1400 1625kHz which enables the user to easily tune the popular stations in this band The receiver is built in a readily available plastic case using widely available components PORTABLE SIGNAL TRACER This versatile signal tracer is a further addition to our build your own test equipment series This unit has three probes for checking a f rf and e h t the latter for checking corona and high voltage breakdown PLUS THE REGULAR TAKE 20 AND LC OF THE MONTH SERIES AND OTHER CONSTRUCTIONAL
233. heck the remaining voltages in Fig 1 Injecting an audio signal or just touching with a screwdriver at i c pin 3 Tr2 base and Trl base should produce progressively louder response from the speaker With the pickup plugged in some stray hum will probably be picked up from the mains Loud positive feedback squeals will be produced if the pickup is brought near the unit as it is sensitive enough to detect the stray field of the loudspeaker voice coil uses The telephone pickup is extremely sensitive to stray field from the mains and the unit will produce a loud hum if the pickup is near any mains appliance This hum can always be minimised by setting the pickup at a certain angle On the modern pattern Post Office desk telephone the best place to attach the pickup is usually high on the right hand side On the older types it is at the back and on STD pay telephones it is at about an An internal view of the completed telephone amplifier inch below the cord entry on the left hand side of the case In these positions both sides of the conver sation will be amplified to loudspeaker volume The best point is easily found by experimenting for the loudest volume from the unit with the telephone producing a continuous sound such as a dialling tone The maximum volume that can be used is limited by the onset of feedback whistles caused by the telephone handset picking up the sound from the loudspeaker Feedback should be avoid
234. icon integrated circuit flatpack is used in the audio output stage Besides simplifying con struction this tiny unit proves cheaper than the equivalent discrete components It delivers just under one watt of audio power quite adequate for this use and operates here with the absolute minimum of external components The signal from the telephone pickup L is first amplified by two conventional common emitter 648 stages Tr and Tr2 coupled by C4 These transistors are very high gain but inexpensive silicon planar types and they are run at a fairly low collector current of about 2004A to minimise noise High frequencies are attenuated by collector base feedback capacitors C2 and C5 in each stage This both ensures stability and gives a useful reduction in noise when the amplifier is used at full gain on a weak signal there is no point in trying to amplify treble frequencies which simply are not present on the telephone line For the same reason bass is restricted by the values of C3 and C6 which are not large enough to decouple the transistor emitters at low frequencies The amplified signal is coupled by C10 to the General Electric PA234 integrated circuit This contains all the active components of a conventional Class B audio amplifier equivalent to six n p n transistors one p n p transistor three diodes and three resistors The voltage drop across the chain of diodes provides sufficient standing current in the output transistor
235. id Atlantic favours reception of Latin American MW stations on the east coast of South America After midnight is the time to search for the Venezualan stations YVLH 650kHz Radio Giradot in Maracay YVKS 750 Radio Caracas YVRB 960 R Monagas in Maturin YVRS 1020 R Margarita on the island of Margarita YVMV 1150 Ondas del Caribe in Punto Fijo YVOZ 1200 R Tiempo Caracas From the nearby Dutch island of Bonaire Trans World Radio operates PJB on 800kHz with a power of 500kW and it is often a strong signal HJED 820 La Voz de Rio Cauca in Cali HJHN 960 R Sutatenza in Barranquilla HJCC 1010 Bogota HJAH 1070 R Atlantico Barranquilla are regularly heard Colom bians ZFY 760 in Georgetown Guyana and SRS 725 Paramaribo Surinam are heard regularly though a loop is essential for SRS on account of European QRM from 728kHz Charles Molloy 661 years it is apparent that the majority of operators do not make the most of the equipment that they possess There is invariably a reasonable communications receiver capable of resolving c w a m and s s b on the majority of the h f amateur bands but the transmitter is so often a one band affair usually for the 20 metre band and then for the c w mode only While 20 metres is considered the band for DX working there are times when it can go dead for various reasons and when this happens the single band operator can only switch off and go and join the family around the TV With a little eff
236. ime of day or night Sundays included No need to bother with postal orders cheques registering envelopes every time you order We send prepaid envelopes and you make only one payment each month So simple Write for details or telephone 01 648 8422 YOUR FIRST STEP out of the maze Post the Coupon with your cheque or P O for 12 6d The price of 12 6d applies only to catalogues purchased by customers residing in the U K S RP p umm unus ES GEN GANGES ee END m mw Please write your Name and Address in block capitals NAME Novi ADDRESS See dou ea EBXS cee ER Sues a E seve uev DLD HOME RADIO Components LTD Dept PW 234 240 London Road Mitcham Surrey CR4 3HD cuum 1 SU EE GE GE Gene GE CNGES ee 657 Testing and Performance TEST CONDITIONS Input signal 1000 Hz sine wave In constructing and wiring a fairly complex piece Input Pre amplifier one only input at C2 10mV Output at C9 300mV of equipment like the PW 25 25 amplifier there is always the risk of a faulty component wrong connection or dry soldered joint etc hence the With equalising network switch 2 connected and earlier suggestion that it might be worthwhile testing set to Radio the pre amplifiers before connecting the power output modules and supply In making the prototype Tone Control Drive amplifier as shown in the photographs the writer tested each Input at CTO RI9 1t0
237. in list Goldring cartridges magnetic types 850 800 800E amp 800 Super E in stock If in doubt which cartridge sults your player write us with details of existing cartridge and make of deck with B A E All postage refunded with despatch of cartridge ordered TWO STATION TRANS INTER COM Excellent baby alarm Instant easy fitting with leads plugs and battery All you require 52 6 5 TRANSISTORISED AMPLIFIER 3 watt 9V operation Size 22 x 2 x 1 82 8 1 6 Extra High Torque MINI MOTOR 43 to 12V 14 x iin 5 1 9 000 r p m SUBSTITUTION BOXES Capacitance 25 6 1 6 Resistance 82 8 1 6 Both full range and complete Full details in list TEST PRODS Flexible unbreakable 24in Red and Black leads thin 4 in prods 11in plugs 4 9 1 2 CROC CLIPS Plated with screw or with red black hndles 6d each 5 doz 1 Many other types in list RECORDING TAPE Finest quality British Mylar STANDARD vin 600tt 7 8 5iin 900ft 10 7in 1200ft 11 8 LONG PLAY Sin 900ft 10 5fin 12001t 11 8 7in 1800 t 18 1 3 reel Still the finest quality and value obtain bli able MICROPHONES CRYSTAL MIC91 Hand desk 16 8 MIC45 curved hand grip 19 6 CM21 two tone grey hand desk 10 8 1 3 Stick 60 20 3 1 6 each type Cream plastic hand type with Strut stand switch and 2 leads with 2 5 and 3 5 plugs 12 6 1 3 Lapel or hand with clip 6 6 1 CM70 Machined metal tapered stick type with neck cord and ad
238. iniature invisible beam projector and photocell receiver for use with Junior Photoelectric Kit Price 10 6 Post and Pack 1 6 U K Commonwealth Surface Mail 2 Air Mail 4 YORK ELECTRICS 335 BATTERSEA PARK RD LONDON S W 11 Send a S A E for full details a brief description and Photographs of all Kits and all 52 Radio Electronic and Photoelectric Projects Assembled night kits Due to huge purchase these superb U S A construction kits can be offered at 25 FANTASTIC LOW PRICES 50 off recommended list prices Absolutely complete with most detailed construction and operating books Available from all branches or by mail order for 7 6 CARRIAGE AND PACKING on each kit Two kits or more carr free KG 865 50 Watt Stereo Amplifier Kit DELUXE FEATURES All Silicon Transistors for Stability Gleaner Sound Extremely Wide Power Bandwidth and Frequency Response S0W IHF Power Out Dut Specially Selected Low Noise Preamp Transistors Two Printed 84W continuous sine wave Response 1dB 18 to 30 000 Hz Output Impedances 4 through 160hms plus stereo headphones IM Distortion under 1 Output 50W IFH 25W per channel Cirenit Boards tor Fast Easy Assam A goar ma MELLE mized 4 1 at rated power bly Convenient Front Panel Stereo put Sensitivity Magnetic Phono 6mV Tuner and Auxiliary 500m V Po uireme t 230 Headphone Jack Toak nihed 250 SoHE mes s Power Requirement 2 Ex
239. ircuit LAMPS 250V 15W MBC Panel lamps Ideal Sives linear control making up displays etc Length 2 in of DE righyness x lin dia Bpecial offer 10 for 1 deni RM a c j d c commuta tor motors fitted to portable electric hand drills Fita standard 2In condult P amp P 6J S YNCHRONOUS MOTORS S EN 50Hz self starting Model 87 30 Model B7 E RPM 30 Clock box 240V 50Hz 600W Price 59 8 Motor 2 RPH 20 Type MA 23 Low P amp P 2 6 Torque Hysterosis Motors 1 60 RPM MEMORY CORE STORES 1 20 RPM 1 12 RPM 1 5 RPM 42 x 522K bit 5 1 RPM 25 each Fitted one way ferrite core 4 clutch 1 12 RPM 1 6 RPM 1 4 RPM store complete 1 3 RPM 30 each P amp P on any of ith 84 OA 10 above 5 each load diodes Ideal for build NEW COMPLETE TELE ing computer PHONE DIAL ASSEMBLIES tore or hold sw Clear Perspex dials no ing information In binary form Price markings 20 each 45 P amp P 7 6 Handbook on use of P amp P 5 core stores 2 6 M RIGHT ANGLED GEAR BOXES Suitable for rotating transmitter aerials Gear boxes give a drive of 14 5 at right angles to the input Driveable through the l p shaft only Dimen sions 4 wide 34 deep 41 high Robust construc tion in cast iron Price 59 6 With pulley and ball race shaft mountings Price 79 6 carr 15 OSCILL
240. iron with a 15 watt nickel plated bit Designed to enable you to weld reliable joints accurately Model CN240 volts Special low price Act Now Only29111 MONEY BACK GUARANTEE P amp P I J M KING K 17 Buckridge Portpool Lane London E C 1 ENAMELLED COPPER WIRE S W G Per Jib reel Per llb reel 18 22 11 3d 16 6d 23 30 11 9d 17 6d 31 35 12 3d 18 6d 36 40 15 24 41 44 17 9d 29 6d Orders despatched by return of post Please add I per item P amp P Supplied by Banner Transformers 84 Old Lansdowne Rd West Didsbury Manchester 20 TRADE ENQUIRIES INVITED BUILD IT in a DEWBOX quality cabinet 2in x 24in x any length D E W Ltd Ringwood Road FERNDOWN Dorset S A E for leaflet Write now Right now THE NEW ELECTRONIC MUSIC FOR YOU Then how about making yourself an elec tric organ Constructional data available full circuits drawings and notes It has 5 octaves 2 manuals and pedals with 24 stops uses 41 valves With its variable attack you can play Classics and Swing Write NOW for free leaflet and further details to C amp S 20 Maude Street Darlington Durham Send 4d stamp BIG BARGAIN PARCEL 13 POST PAID Containing multi contact relay transistors resistors some high stab rectifiers diodes capacitors pots knobs etc 4 WATT GRAM AMPS Volume and tone controls mains operation 3Q output new and boxed 72 6 PAID SALOP ELECTRONICS Cal
241. iscoteque amplifier 638 to lOkO if the output loading is more than 50k The output loading should be not less than 10kO unless lower values are chosen for VR1 RI etc Either amplifier in the MC1303P may be independ antly equalised using the component values in Figs 4 or 5 An example is the mixer circuit in Fig 7 which was designed for a discoteque amp lifier One amplifier has a flat response and takes the signal from a disc jockey s microphone the other amplifier provides RIAA equalisation for a mono magnetic record pickup The small physical size of the i c s makes it possible to build the equalisers and mixers very smail CA3048 The RCA CA3048 is a 16 lead flatpack containing no less than four separate identical amplifiers Characteristics of each amplifier are shown in Table 2 The circuit of half the device i e two amplifiers is shown in Fig 8 where component references are given for one amplifier only The circuit of the other two amplifiers is identical and separate except that all the earth connections are to one pin pin 5 Each amplifier operates as follows Positive and inverted inputs are received by a long tailed pair amplifier consisting of Darlington connected pair Tri Tr2 on the positive input side and Tr3 on the other Base bias current for Tri is fed through R3 from the potential divider R2 R1 D2 D3 in which D2 and D3 provide temperature compensation for the emitter base junctions of T
242. ise at any pre set time up to 60 min and in conjunction with the AUTO setting will better than 70dB Front panel brushed aluminium 9 19 6 switch on the appliance again next morning with black knobs and controls Size 8M x 1 1 x 4in post 3 6 The clock measures 43Wx 12Hx 34D overall from front of drum i ER of 2 30 SPECIFICATION switch SPEC 210 240V AC SOHZ operation switch rating 250V 3A Com Power output 15 w R M S into 8 ohms using a 35 volt supply Frequency response plete with instructions HUNDREDS OF APPLICATIONS 30 to 300 000Hz 1dB Distortion 0 02 Signal to noise better than 70dB Input COMPLETE WiTH KNOBS sensitivity 250mV Into 100 K ohms Loudspeaker imp E ira bso imo pareto Pom Balarin ri peus LASKY S PRI CE 6 19 6 Post 3 6 Size 3 x 2 x Min 89 6 post 3 6 30V unstabilised sutficient to drive two 2 30 s and a Stereo 60 for domestic PZB Lu 99 6 FANI uL DEVELOPMENT 35V stabilised deai for driving two Z 30 s and a Stereo 60 for low efficiency PACKAGB RE For Stereo 60 two 7 19 6 ies AD 309 K Zand ore 25 19 18 S PRECISION PICK UP ARM COMPLETE WITH AD 76K The new MAGNETIC VELOPMENT ii CARTRIDGE precision MAGNETIC RECORDING TAPE FROM THE U S A ERUS RI AT LASKY S RECORD LOW PRICES up arm ready din Message tape 150ft jin Long play 1200h Myr 18 8 feted aene 3in Message tape 225ft Skin Triple play 2400ft 0 outstanding Wc cra AD 76K magnetic 3in Mes
243. it 4 Kit rr D Carr amp Ins 35 4040 The ideal stereo tape desk for use with Telephone di 3 STD 0602 existing hi fi stereo em to give gee S9gns per pair the full enjoyment of stereo tape recordin a ES play back s P amp P 10 euch 13 pair 28gns per pair luit 5 Kit 23 10 0 each 18 19 25 amp 53 TOTTENHAM CT ROAD LONDON W 1 Telephone 01 580 2255 4532 7679 pene idee Monge ban uirum Co Open 9 6 pm Monday to Saturday Thursday until 7pm 611 The demands become greater of course Kit 20 3 Max Power Input 40 watts Frequency Range 40 20 000 c p s Standard Impedance 4 Q or 8Q Peerless PEERLESS FABRIKKERNE A S 11 Gladsaxe Ringvej 2860 Copenhagen Denmark and as specialist manufacturers of Loudspeakers we naturally make greater demands and meet them Our new kits incorporate the latest progress in the Loudspeaker f eld and the detailed mounting instructions included in each Kit make the mounting effortiess At the same time you get a quality product at a reasonable price For further information please apply to Messrs P F amp A R Helme Summerbridge Harrogate Yorks HG3 4DR Telephone Darley 279 0423 72 279 The New Picture Book way of learning BAS IC ELECTRICITY 5vo is ELECTRONICS 6vois You ll find it easy to learn with this out standingly successful NEW PICTORIAL METHOD the essential facts are explained in the simplest
244. it back to back with the wiring inside the components outside and of course the screen in the middle Completion of the pre amplifier circuit boards is by soldering flying leads to components and other points on the boards that connect with front panel controls the selector switch S and S2 and supply 652 NN MN QS NA RRA A d A am M and earthing points It is most essential that these them afterwards All leads shown coming away from the circuit boards as in Fig 8 should be regarded as R UN vu WN MA NW V yn DM SA AM MA WA leads are fitted before the circuit boards are mounted on the chassis as it would be very difficult to connect flying leads and the best way to identify them is to use coloured wires Panel Controls and Selector Switch Connections to the volume balance and tone controls etc are shown in Fig 9 Providing the leads from the input pre amplifier boards via R18 to the balance control VRi are short and they should be no more than two or three inches long they need not be screened This also applies to leads connecting the tone controls and the filter switches The leads from the output of the tone control drive amplifier boards C23 to the volume controls and from these to the power output modules and to S5 the stereo mono switch must be screened This is to prevent instability due to capacitive coupling since these leads are fairly long and pass close to the input ends of the
245. it without arm 26 0 0 23 8 Philips GA202 69 0 0 6014 Thornes TD150A Mk 2 w Arm 43 13 0 38 19 Thorens TD150AB w Arm amp Base 41 9 0 41 10 Thorens TX11 Cover 4 2 0 310 Thorens Ipse be 46 16 0 42 5 Thorens TD1 75 17 O 66 19 Thorens TDi24 P amp C 9 Arm 12 0 0 10 16 Thorens TDi24 P amp C 127 Arm m re 15 4 0 13 13 Pioneer PL11AC w Arm Base amp Cov 48 17 0 40 19 Pioneer PL11AC w ATISX Elipt Cart 73 2 0 55 18 PICK UP ARMS Goldring L69 Arm 918 2 814 Goldring L75 Arm 13 12 6 11 19 Transc Fluid Arm 9 or 10 22 H 0 19 12 SME 3009 with S2 Shell 34 0 29 19 SME 3012 with S2 Shell 36 14 0 31 19 Audio Tech AT 1005 1919 0 17 0 AMPLIFIERS TUNERS amp TUNER As Akai AA6500 Tuner Amp 142 10 AR Amplifier 114 0 Wood Case for above Walnut 11 10 AR Receiver Tun Pre Amp Amp 380 15 Wood Case for above Walnut 18 14 ARD 2000 Amp Metal 46 4 ARD 2000 Amp Wood 49 7 Armstrong 521 R 56 0 Armstrong 523 AM EM Tun 53 15 Armstrong 524 FM Tun 41 17 Armstrong 525 Tun Amp 91 17 Armstrong 526 Tun Amp 104 14 Amstrong M8 Decoder 9 10 Armstrong M4 Decoder 9 10 Cambridge P40 Amp 75 0 Dual CV20 Amp 48 10 Dual CV40 Amp 73 10 Dual CV80 Amp 89 10 Dual CT15 Tun 81 15 Dual CTi6 Tun 105 0 Dual CR40 Tun Amp 178 1 Decca A3000 Amp 69 10 Decca T1000
246. ith library cases pp Y 7 9 3 reels and over Post Free at 6d extra each RADI Tel 01 636 3451 OXFORD sT o LAL DA TOTTENHAM COURT RD A Menon l e 667 We ll 2 000 a year technician We re going to give 175 men just about the finest apprenticeship in the world If you re 154 to 174 and bright at Science or Maths you could be one of them We ll train you to be atop Navy technician in electronic air or marine engineering And that means you ll take equipment like radar missiles helicopters diesels comput ers and automation in your stride Our training will make you a 2 000 a year man With more to come And some of the best firms in the country will be keen to sign you on when you leave us Send the coupon for your free booklet With 175 top technicians to train you re in with a chance ROYAL NAVY Roval Naval Careers Service Apprenticeships 830 X87 Old Admiralty Building Whitehall London W 1 Please send me without obligation the free booklet on Artificer Apprenticeships Name Address Date of birth Enquiries from U K residents only v T i 668 TRANSISTORS DIODES amp SEMI CONDUCTORS AA120 2 BRBY95A 8 6 0C23 6 6 OC140 5 XK143 Germ AC107 3 GETI113 2 6 O0C25 6 OC169 8 6 jup to 70 meg AC126 2 8 GET872 4 6 0C26 7 6 0C170 4j 2 8 AC128 2 8 GET875 4 6 0C28 8 6 OCI7l 2 8 PL4003 200v
247. ize as in Fig 7b together with the 20s w g aluminium or tinplate screens that are fitted between the boards as in Fig 7a The boards and screen are spaced iin apart from each other with spacers but note that one board has attached to it a length of 2 x jin aluminium angle for securing the assembly to the chassis These angles must be fitted so that when each assembly is placed in position as in Fig 7c the angles will be facing toward each other ft is best to assemble the blank circuit boards together with their screens and try them in position on the chassis to ensure that they comply with Fig 7c Then mark each board so that it can be identified as to which channel it belongs and which ends will be used for input and output respectively Although the circuitry for the right and left hand channels is identical the component layout on the board is in opposition as they are mounted back to back hence the reason for identification with respect to channel allocation and input and output ends The component layout and connection dia grams given in Fig 8 should help in getting the boards the right way round and as can be seen the layouts are virtually mirror copies of each other The input pre amplifier for the right hand channel is an exception however as it also carries the large 50004F positive rail decoupling capacitor C24 and the 1 5 kQ voltage dropping resistor R35 When the boards have been assembled and wired they should f
248. k Advance Mechanism Checks Distributor Cam Wear Built in D C Power Supply Reliable Solid State Circuit Your car gives More miles per gallon Improved performance Greater reliability Recommended List Price 212 10 0 9 GNS Available Assembled y We offer you fully tensilised polyester mylar and TP V C tapes of identical quality hi fi wide range recording characteristics aa top grade tapes Quality control manufacture They are truly worth a few Recommended List Price 84 19 6 24 GNS JASON TAPE or cheap imports YOURSELF more coppers than acetate sub standard jointed TRY ONE AND PROVE IT ALL SILICON TRANSISTOR The NEW KG 980 Stereo FM Receiver Kit Designed to Satiefy the Moat Critical Listener R F and LF Panels Assembled and Aligned Front P and Speaker Muting Switch Full Controls including Tape Monito y tput Usable I H F Sensitivity 3 7 Frequency Response 142 30 to Harmonic Distortion less t than 1 0 M Suppreasion more than per channel 34W continuous sine wave Frequency Response 10 18 to pu 000 Hs Power Bandwidth 20 20 000 Hz at 1 harmonic distortion Two R F Stages Btereo indicator light Recommended List Price 62 19 6 89 GNS Assembled 49 GNS Teak Case 6 GNS Extra STAR ROAMER 5 Band Shortwave Receiver Kit Bandspread electrical calibrated 0 100 Sensitivity 10V jor 10d B signal to noise ratio I F Bandwidth amp
249. kHz at 6dB down Beat Frequency variable 0 5kHz Spenker fin perma nent magnet type Power ae fused transformer opera Headphone Output low rl s Valve Comple ments 1 6 BE6 1 6H R6 1 12AX7 1 6AK6 or 1 6AR5 Power Requirements 230 2507 50Hz a c 15W Covers 200 to 400kHz and 550kHz to S0MHz in b Band switched Ranges Superheterodyne Circuit includes controlled regenerative I F stage A V O reduces fading and blasting A N L cuts noise io a minimum Aerial Trimmer effectively peaks incoming signals for best reception Illuminated 8 Meter Large Easy to Read 7iin Slide Rule Dial Recommended List Price 21 19 0 14 GNS Assembled Price 19 GN8 100 in 1 Electronic Science Lab LOOK AT THE PROJECTS YOU CAN BUILD Electronic Scale Electronic Timer Signal Generator Hybrid Light Meter Signal Injector Morse Code Buzzer Electronic Cat Metronome Code Flasher CW Monitor Ohmmeter Boat Horn Hybrid Radio Hybrid Voice Relay Air Powered Radio Polarity Checker Valve Checker Includes Dual Headset Photocell Speaker Meter Aerial 9 Transistors Recommended List Price 16 8 0 9 GNS KG 640 20 000 ohms Volt VOM Kit BIG PROFESSIONAL SIZE 62 RANGE MULTIMETER A C Volts 19 Ranges 0 2 4 8 16 40 80 200 400 800 1 600 2 000 4 000 V D C Volts 12 Ranges 0 0 8 1 6 8 16 40 80 200 400 800 1 600 2 000 4 000 V Output Volts 8 Rang 4
250. ks down buried BUILT ALMOST BLINDFOLD IN UNDER 15 MINUTES metal objects it signals exact location Ideal for absoiute beginner from 8 years of age upwards with loud audible sound no phones SPECIAL PRICE TO CLEAR STOCKS OF COMPONENTS ONLY 10 6d 1 used FINDS GOLD SILVER LOST 2 6d P amp P for all parts including beautiful case Germanium semi conductor tuning condenser personal phone COINS JEWELLERY KEYS WAR wire nuts screws SIMPLE AS A B C INSTRUCTIONS Will make an exceptional Christmas present Parts available SOUVENIRS ARCHAEOLOGICAL separately Money Back Guarantee PIECES METALLIC ORE NUGGETS EN Lu ULT ur MEME e M M ERE Tos amenne fuii at preme i SHO FEMA ES BEA NSISTOR RAD certain objects buried several feet below Can be built in one evening ground No knowledge of radio or electronics required Can be built with ease in one short evening by anybody from nine years of age upwards with At last Alter trying countless circuits searching for easy build work the wonderfully clear easy to follow first time short waver Giving advanced world wide performance we chose step by step fully illustrated this Sky Roma Anyone from 9 years up can follow the step by step ONLY instruetions it really is easy easy as ABC fully illustrated instructions We built ten propotypes and as A B C Fully vransistorized every one worked first time no soldering necessary 76 stations logged on 47 6 no valves Uses standa
251. l 4 6 EF183 2 6 PCL82 3 6 PY33 4 8 90P3 2j EF184 2 6 PCF86 3 6 Ul191 3 6 30PLI 4 6 EY86 3 6 PCL83 2 6 6F23 8 6 30PI2 4j 30F5 2 3 On 2 valves or more 6d postage amp packaging UHF TUNERS TO SUIT MOST MODELS ie FERGUSON 850 900 Chassis K B G E C etc 50 P amp P 10j VHF TUNERS MOST MAKES 20 delivered Discount for quantity Dept T 8 THORNBURY TRADE DISPOSALS Thornbury Roundabout Leeds Rd Bradford Tel 665670 est 1943 JOHNSONS Tei 24864 New CV2 a unique triple purpose VHF kit for the Amateur enthusiast Integrated converter receiver and tuner feeder Fantastic single trans istor gerformance Comprehensive kit of high grade parts with three coils covering 80 178MHz 9v battery etc together with simplified diagrams and instructions Price complete 4 post packing and insurance paid direct from makers S A E for literature JOHNSONS RADIO St Martin s Gate Worcester WR12DT KEYNECTOR The safe quick way to connect electrical Send for full details EB INSTRUMENTS 49 53 PANCRAS ROAD LONDON NWA Tei 01 837 7781 1N4001 1N4002 1N4003 1N4004 1N4005 1N4006 1N4007 1N4009 1N4148 2G210 28240 28301 28302 20303 sw sra ic Sien Power MCI 2G30 ACY 19 a08 IG AGYIM 5f 100 L1 500 4 9 2G309 20371 2G374 85 6 ACY 2 3 6 1N4003 and 42 B 2N2646 10 6 2381 ACY28 3 8 AMP 300 400v Motorola 2G382 6 ACYS4 4 25
252. l be gladly sent without any obligation To British National Radio School Reading Berks Please send FREE BROCHURE fo BRITISH NATIONAL RADIO SCHOOL 688 USEFUL BOX 3 x 31 x 12 with fixing bracket 2 6 Postage 2 25 per dozen post free NEW F M TUNER Range 87 to 107 MHz Attractively finished metai container with cast front escutcheon Case size 13in x Tin x 3 in high Mains transformer Metal Rectifier and Valves ECC85 EF89 EF80 ECC82 as cathode follower EM84 tuning indicator 2 x AF117 and 2 diodes A really fantastic performer Price 16 tax paid and carr paid or with Stereo Decoder 24 66 ELMS ROAD ALDERSHOT Hants CLOSED WEDNESDAY S A E for enquiries please G LAD S Q N E I AD IO 2 mins from Station and Buses FULL GUARANTEE Aldershot 22240 Thinking of High Fidelity You should read the Goodmans High Fidelity Manuals Goodmans High Fidelity Manuals are of vital interest to you and contain constructive and informative articles on all aspects of High Fidelity sound One manual contains specifications descriptions and full colour illustrations of the entire current range of loudspeaker cabinets systems amplifiers and F M tuners The construction manual contains the information needed by those enthusiasts who prefer to make their own High Fidelity or musical instrument loudspeaker systems These manuals are available free from
253. language one at a time and each is illustrated by an accurate cartoon the latest research into simplified learning techniques This has proved that the PICTORIAL APPROACH to learning is the quickest and soundest way of gaining mastery over these subjects type drawing The books are based on TO TRY IT IS TO PROVE IT RBRER ERE REPRE ERR ERE eS This carefully planned series To The SELRAY BOOK CO 60 HAYES HILL HAYES BROMLEY KENT BR2 7HP of manuals has proved a Please send me WITHOUT OBLIGATION TO PURCHASE one of the valuable cour in reed above sets on 7 DAYS FREE TRIAL I will either return set carriage paid Electronics Radio and in good condition within 7 days or send the following amounts BASIC Telecommunications B ELECTRICITY 75 Cash Price or Down Payment of 20 followed by 3 fortnightly payments of 20 each BASIC ELECTRONICS 90 Cash Price WHAT READ ERS SAY E or Down Payment of 20 followed by 4 fortnightly payments of 20 each This offer applies to UNITED KINGDOM ONLY Overseas customers BEST BOOKS IN THIS COUNTRY On going through these books I have found they are the best books cash with order prices as above I have ever had in this country S K A London N W E Tick Set required Only one set allowed on free trial B Basic ELECTRICITY BASIC ELECTRONICS KEY TO THE KNOWLEDGE Prices include Postage and Packing sour books have been the key to the knowl
254. leads KIT 10 10 0 ALSO AVAILABLE READY BUILT AND TESTED 12 10 0 Post 5 MODEL TM MINI TESTER The first of Lasky s new look top value meters the TM 1 is a really tiny pocket multimeter providing big meter accuracy and performance Precision movement calibrated to 3 of full scale Click stop range selection switch Beautifully designed and made impact resistant black case with white and metallic red green figuring Ohms zero DC V 0 10 50 250 1 000 at 1K OP V AC V 0 10 50 250 1 000 at 1K OPV DC CURRENT 0 1mA 100mA Resistance 0 150kt Decibels 10dB to 22dB Complete with test leads battery and instruc 3iin ti A LASKY S PRICE 39 6 post 26 MODEL TM 5 5K OHMS V POCKET MULTIMETER Another new ook pocket multi meter from Lasky s providing top quality and value The slimline impact resistant case size 4 inx 2ginx 1gin fitted with extra large 2gin square meter Read ability is superior on all low ranges making this an excellent instrument for servicing transistorised equipment Recessed click stop selection switch Ohms zero adjustment Buff finish with crystal clear meter cover DC V 3 15 150 300 1 200 at 5K OPV AC V 6 30 300 600 at 25K OPV DC Current 0 300L A 0 300mA Resistance 0 10k 0 1M2 Decibels 10dB to 16dB Complete with test leads battery and instruc tions LASKY S PRICE 49 6 post 26 jin OTHER GARRARD UNITS FROM STOCK AUTOC
255. lers welcome 23 Wyle Cop Shrewsbury Shropshire S A E for lists 692 MISCELLANEOUS continued MISCELLANEOUS continued MUSICAL MIRACLES Drum Cymbals Waa Waa and Fuzz modules New unique eflects units Percussion etc Good waa waa kits 49 Famous Mister Bassman bass pedal unit Also bargain components list of reed switches etc Send S A E NOW D E W Ltd 254 Ringwood Road Fern down Dorset DO IT YOURSELF PRINTED CIRCUIT KITS AMAZING VALUE Each pack contains P C Boards assorted sizes Etchant Resist Etching Tank Full instructions Price 16 and 30 extra large C W O CLIFFORD ELECTRONICS Dept P W 14 Lynford Gardens Edgware Middx VICTORIA STREET S unique magazine and paperback centre Hills Westminster Prac tical Wireless always in stock HILLS WESTMINSTER LTD 5 Artillery Row Victoria Street S W 1 01 222 6165 TV NOTES for UFO Detection and_ 2 Optical Circuits 9 6 Optical radiation De tector Circuit electronic memory 9 6 UFO Daily Flight Patterns American British 7 6 Radar amp Electronic Publica sions Highlands Needham Market Suffolk 6 or 12 volt FLUORESCENT LIGHTS 12 ins 8 watt tube ample light for camp ing caravan or boats etc fully transis torised low battery drain Only 65 post paid or in kit form 57 6 post paid 4 watt GRAM AMPS Quality gram amplifier volume on
256. ll G4AR 662 Going Back by Colin Riches and Arthur Dow 673 DIPC Magazines Limited 1969 Copyright In all drawings photographs and articles published in Practical Wireless is fully protected and reproduction or imitations In whole or in part are expressly forbidden All reasonable precautions are taken by Practical Wireless to ensure that the advice and data given to readers are reliable We cannot however guarantee it and we cannot accent legal responsibility for it Prices are those current as we go to press All correspondence intended for the Editor should be addressed to Fleetway House Farringdon Street London E C 4 Address correspondence regarding advertisements to Advertisement Manager Fleetway House Farringdon giest London E C 4 Orders for back numbers should be addressed to IPC Magazines Ltd Back Numbers Department Carlton House Gt Queen Street London W C 2 623 NEWS NEWS NEWS BBC Radio Londo ES E Predicted serico aron f a Weybridge 3 Approximate boundary of satisfactory reception E with car radios and in receivers having buit m The unshaded pari indicates the approximate area of satisfactory reception with Qood outdoor aerials SCALE b p SwARAOW BLO wig Stanes an Ro Sunbury t a Epsom g re P Ls 1 LT wowa Kingswood m Farnborough Mickleham ji Hentield a BBC Radio London opened recently
257. llege provides first rate postal courses for Radio Amateurs Exam R T E B Servicing Cert C amp G Telecoms A M S E Elec Guide also gives details of range of certificate courses in Radio TV Servicing Elec tronics and other branches of engineer ing together with particulars of our remarkable terms of MAINS WIS c m CR cage NULTI MINI TWIN VICE TRANSISTOR EQUIPMENT ces PLUS 3 MAINS UNIT Provides three separate Switched output voltages 6v 74v and 9v DC attrac tive case with Indicator light malne lead output sockets piua ond isad Size 44 x 3 x n 57 6 Extra lead with DIN plug for P amp P 2 6 Cassette Recorders 7 6 S MAINS UNIT for transistor equipment using 74v Complete with DIN plug for power socket Can also be supplied for a 6 volt output complete with suitable plug State make model and PM required 45 P a AN UNIT FOR USE WITH 12v CAR BATTERY Suitable for running transistor radios etc State output read 6v 71v or v Price 35 in cluding fused lead P amp P 2 6 MAINS UNITS For single outputa 6v 9v 12v 18v 38 6 For two separate outputs 44v 4iv 6v 6v Sv 9v 42 6 P amp P 2 6 per unit Please state outputs regd An extra Pair of hands for those tricky jobs ASSEMBLY SOLDERING GLUING WIRING DRILLING ETC INDEPENDENT ADJUSTMENT OF THE TWO VICE HEADS TO ANY ANGLE WITH POSITIVE LOCKING JAWS WILL FIRMLY GRIP ROU
258. lues 10 ohms to 10 meg 4 w bw 1 w 20 8d 14 w 8d 2 w 1 w 10 6d HIGH STABILITY w 2 10 ohms to 10 meg 2 Ditto 5 Preferred values 10 ohms to 22 meg 9d WIRE WOUND RESISTORS 5 watt 10 watt 15 watt 10 ohms to 100K 2 each 21 watt 1 ohm to 8 2 ohms 2 ah cei el Loreto arius er dandi Q MAX CHASSIS CUTTER Complete a die a punch an Allen screw and key hin 16 6 jin 17 6 lin 19 6 Ijin 24 2 44 in 18 8 lin 19 6 Hin 20 6 1iin 29 2 in 57 3 in 16 9 14in 19 6 1ljin 21 6 in 89 9 lin sq 36 6 TRANSISTOR MAINS POWER PACKS FULL WAVE 9 volt 500mA Size 4 x 3 x gin Metal case 78 fe Crackle finish Output terminals On oft switch Halt Wave 9 volt 50mA Size 2 x 1jin Snap terminals 36 MAINS TRANSFORMERS in 250 0 250 50 mA 6 8 v 2 amps centre tapped 250 0 250 80 mA 6 8 v 4 amp 250 0 250 80 mA 6 8 v 8 52 6 3 v 1a orb v 2a 350 0 850 80 mA 6 8 v 8 52 6 8 v 1a or b v 2a 00 0 300 v 120 mA 6 8 v 4 a C T 6 80 28 MINIATURE 200 y 20 mA 6 8 v La 21 x 2x 1 in MIDGET 220 v 45 mA 68 v 2 a 2 x 23 x Zin HEATER TRANS 8 87 l 8 sees Ditto tapped sec 1 4 v 2 8 4 5 6 3 v 1 amp GENERAL PURPOSE LOW VOLTAGE Outputs 3 4 5 6 8 9 10 12 15 18 24 and 30 v at 2 amp 88 lamp 6 8 10 12 16 18 20 24 80 36 40 48 60 38 AUTO TRANSFORMERS 0 115 230 v Input Output 60 w 18 6 150w 38 500w 5 1000w 12 CHARGE
259. mV circuit board individually before assembling them Output at C28 400mV and then again after assembly and wiring as a With fone controls connected and Got neutral complete pre amplifier on the chassis This 1s quite USA Lia x Cat COO easy to do if an audio signal generator and audio Complete Pre amplifier voltmeter are available The tone controls etc can Input Input be temporarily connected for individual testing and each board hooked up to a 22V battery Those able m id m Replay 1 muse to do this will find the table of input and output Cer PU 70 80m V signal levels of some use Before switching on the completed amplifier ensure All inputs for 1 volt r m s output at C23 VR4 that loudspeakers and or suitable dummy resistive Volume controls off Balance control at neutral Tone controls at neutral Signal level at module inputs sliders of VR4 for full output should be 700 to 800mV r m s loads are connected at the output speaker sockets Set the volume control to zero and inject a signal at the radio input preferably a 90 to 100mV sine wave at 1000Hz Advance the volume control just DC Supply sufficiently to lightly load the output stage and then Positive point on module take off point for repeat the procedure for the other channel For those pre amplifiers 35 36V without an audio signal generator and audio volt Pre amplifiers positive rail junction of meter further tests can only be made by listening C24 R35 22 24
260. me There were very few receivers but the station had arranged for the programme to be relayed over loudspeakers to a nearby civic centre These listeners were privileged to be the first to hear the famous station call letters KDKA East Pittsburgh The programme continued for some eighteen hours long by even present day standards and a few hours later the station was again on the air and has continued to this present day with regular programmes still using the same call sign The origins of KDKA dated many years earlier than 1920 As early as 1915 a Dr Frank Conrad who later became Assistant Chief Engineer of Harold W Arlin the world s first full time radio announcer Westinghouse had built a radio receiver to enable him to hear the time signals broadcast from the Naval Observatory at Arlington He did this primarily to test the accuracy of the watch and a 5 bet was the motivating factor The reception of these signals sparked the enthusiasm of Dr Conrad and by July 1916 he was on the air with his amateur station 8XK Dr Conrad was however unable to pursue his hobby for long because the entry of the United States into the First World War caused cancellation of amateur licences in April 1917 During the emergency both Westinghouse and Dr Conrad were able to gain invaluable experience as the station was allowed to operate under a special authorisation for the testing of new radio equipment for the British a
261. me with one of Dr Conrad s two sons acting as the master of ceremonies By the late summer of 1920 the broadcasts had grown so popular that a Pittsburgh store ran an advertisement in a daily newspaper for the sale of radio receivers on the strength of being able to hear these transmissions The date was September 29th 1920 and it was probably the one single event that brought about the first broadcast Among the people who saw the advertisement was H P Davies Vice President of Westinghouse He was already a keen follower of the work being done First orchestra developed for exclusive radio work was KDKA Little Symphony Orchestra with Victor Saudek conducting How the family used to listen in 674 The Aeriola Jr had range of 15 miles and used to cost about by their company employee and the advertisement made him realise that if regular programmes were provided for the people they would quickly want to buy receivers of their own Mr Davies began by winning over the other officials of Westinghouse and this was done so quickly that the application for a licence was sub mitted to the authorities on October 16th and the forthcoming election night was chosen for the grand opening The enthusiasm of the small group was such that it was under five weeks between the newspaper advertisement and the station opening For this first scheduled broadcast there was no studio a single room accommodated the transmitter the reco
262. mechanical filter but is at least twice as sharp as can be obtained using conventional i f circuits and results in an i f bandwidth of less than 6dB 25dB 3 5 to 29 MHz 1 5 to 200 MHz W CAMERON 4kHz at 6dB This is just adequate for a m while results on s s b are very good indeed By taking special care with the oscillators a stability of a very high order is achieved The receiver uses the double conversion principle in which the second converter is tuned covering the range 1 5 20MHz This frequency range is chosen so that this unit with the following i f amplifier serves on its own as a complete Top Band receiver The oscillator of the first converter is switched to cover all the remaining bands which are fixed tuned The r f stages are peaked by a front panel control This double conversion system has the very great advantage that the same scale calibration and the same tuning rate holds good for all bands with the minor exception that the Top Band calibration is reversed This means that the entire scale length covers only 500kHz and is the same on each band Another advantage is that because the i f has been raised to nominally 1 7MHz 1 5 2 0 from 470 kHz by the second converter the image rejection on the h f bands is improved Typically the image rejection at 2MHz with a 470kHz if can be expected to be 10 or 12dB but with an i f of 1 7MHz improves to 40 to 45dB A bl
263. mpact device which relieves these problems by amplifying telephone calls to loudspeaker volume Its design was prompted by the authors frequent need to take down notes during telephone conversations It can reduce the strain of using the telephone and it could be especially useful in a noisy environment such as a factory The unit can actually save money on long distance calls since it allows a conversation to flow faster It also enables more than one person to listen to a telephone making conferences by telephone possible The unit is portable and can be attached to a Post Office or private intercom in seconds without any unauthorized electrical connection or modifica tion to the telephone It works by detecting the stray magnetic field which exists around a telephone A special magnetic detector which attaches to the telephone by a built in rubber suction cup produces a signal which the unit amplifies to loudspeaker volume Depending on where the detector is attached to the telephone the unit may deliver both sides of the conversation or almost solely the incoming speech Since it is hardly likely to be used for quality music reproduction the units frequency response is deliberately restricted to give the best intelligibility of telephone speech A somewhat unconventional volume control circuit is used to this end circuit The circuit of the telephone amplifier is shown in Fig 1 where typical voltage readings are shown A sil
264. n Amp Philips RH690 Tuner s Philips RH691 Tuner Philips RH781 Tun Amp Phillps RH790 Tun Amp Philips RH580 Amp Philips RH590 Amp Phillips RH591 Amp Pioneer SX440 Tun Amp Pioneer LX440 Tun Amp Pioneer LX800 Tun Amp Pioneer SX770 Tun Amp Pioneer SX990 Tun Amp Pioneer SX1500 Tun Amp Ploneer TX500 Tuner Pioneer TX900 Tuner Pioneer SA500 Amp Pioneer SA700 Amp Pioneer SAS00 Amp a Pioneer SR202 Reverb Amp Pioneer KX330 Tun Amp Quad 303 amp 33 Amp te Quad FM Tuner Quad AM3 Tuner Radford SMT3 Tun Radford SC30 Amp Revox A50 Amp Revox A75 Tuner Rogers Ravensbourne Rogers Ravensbrook Rotel 100 Amp ns Rotel 120 ST Tuner da Rotel 130 Tun Amp 9d Rotel FAX330 Tun Amp Rotel FAX660 Tun Amp Secom SA500 Amp Sansui 350 Tun Amp Sansui 400 Tun Amp Sansui 800 Tun Amp Sansui 2000 Tun Amp Sansui AU222 Amp Sansui AU555 Amp Sansul TU777 Tuner m Sansui TUS555 Tuner ae LOUDSPEAKERS 5 Bridge Street Richmond Surrey 948 1441 till 8pm List Price 31 0 59 0 53 0 59 10 63 0 69 10 59 18 68 1 124 10 97 10 66 7 84 0 168 0 108 5 143 14 36 0 4 9 4 9 5 9 9 19 5 19 4 19 7 19 5 19 2 19 4 9 4 19 9 19 30 9 26 14 45 0 61 19 25 0 4 4 59 0 27 15 29 0 39 15 74 0 33 15 45 10 35 0 51 15 118 13 50 10 510 52 10 131 5 44 10 89 0
265. n Weight 114lb Offered in good working condition 22 10 0 Carr 30 With circuit diagrams Also available B41 L F version of above 15 Kejs 700 Ke s 17 10 0 Carr 30 TO 3 PORTABLE OSCILLOSCOPE Sin tube Y amp Bensiti vity O lv p p OM Band width 1 5 cps 1 6 MHz Input imp 2 meg Q 26pF X amp sensitivity 0 9v p p CM Bandwidth 1 5 cps B00K Hz Input imp 2 meg N 20pF Time base 5 ranges 10 cps 300 KHz Synchronization Internal external Hiuminated scale 140 x 215 x 330 mm Weight 154 lb 220 240 V A C Bupplied brand new with handbook 37 10 0 Carr 19j USED EXTENSIVELY BY INDUSTRY GOVERNMENT DEPARTMENTS EDUCATIONAL AUTHORITIES ETC LOW COST 9 QUICK DELIVERY OVER 200 RANGES IN STOCK OTHER RANGES TO ORDER NEW CLEAR PLASTIC METERS TYPE SW 100 100 x 80 mm 20V D C 59 6 50V D C 69 0 300V D C 59 6 Lamp D C 59 6 amp D C 59 8 300V A C 59 8 VU Meter 75 SEW CLEAR P Type ME SSP 44in x 4jin fronts 8 Meter mA VU Meter lamp A C 5 amp A C 10 amp A C 20 amp A 30 amp A C 58 SEW DESIGNS BAKELITE PANEL METERS TYPE S 80 80 mm square fronts BOA ooie 62 6 50 0 50uA 59 8 50Y D C 49 6 100A 59 8 300V D C 49 6 100 0 100 amp A 57 6 1amp D C 49 6 500A 52 6 o amp D C 49 6 lmA 300V A C 52 6 20V D VU Met
266. n Hy i im Dai Open all day Thursday marty losing 1 pon Seite ter ALL MAIL ORDERS AND CORRESPONDENCE TO 3 15 CAVELL STREET TOWER HAMLETS LONDON E1 2BN Tel 01 790 4821 A This MONTH S Best Buy Complete with spare ear muffs Total Our 4 6 ous sialejod Price 5 18 p Me Available only from us at this price Due to entire purchase of manufacturer s remaining stock this Substantially increased stereo effect Headphones fit the head gently and do not shift Earpieces fit ears snugly Cardanic suspension Tone quality superior to conventional loudspeakers Only expensive studio loud speakers can match the reproduction quality of the K50 Music can be reproduced at concert hall volume preserving the lower bass notes and AKG K50 Dynamic 4 A B fantastic offer is open only while stocks last brilliant treble tones without causing any strain to the listener Stereo headphones High fidelity reproduction due to broad frequency response 20 20 000Hz PLUGS ult zi orme Pg d EE tack 107 5 Pin Din d e Ale pack 155 14 Bin m t 3 6 aci jack en e 5 GARRARD SP25 Pack 1304 Jack Stereo e 96 kH Plus 10 Pack 100 Phone pieg Plug is 3 onoPiug AE m 1 0 1 9 6 carriage Pack 230 3 Pin Socket m 4 6 Normal price 15 11 4 Pack 236 5 Pin Socket 6 Single record playing unit Features include cue and pause and automatic pick up return and switch off
267. n in the world electronics industry the Go Torch will make a useful addition to the equipment in the radio shack Price of the Tilley Go Torch is 2 19s 6d including general purpose burner soldering bit attachment a steel flame spreader for paint stripping and a full cartridge of Tilley Go Gas The latter is replaceable at around 4s 6d each The Tilley Lamp Company Ltd Dunmurry Bel fast Northern Ireland 625 AMATEUR BANDS RECEIVER CIRCUIT Double conversion superhet SYSTEMS AM SSB CW COVERAGE 1 8MHz to 29 5MHz SENSITIVITY 1 54V for 025V a g c and 100mV into detector and S N ratio of 12dB 1 F BANDWIDTH 4kHz at 6dB points 10kHz at 30dB points IMAGE REJECTION 60dB at 1 5MHz 80dB at 3 5MHz 40dB at 28MHz SPURII 80dB on all bands INPUT IMPEDANCE 300 ohms on 1 5MHz 80 ohms 3 5 to 28MHz OUTPUT 1 Watt into 15 ohms POWER SUPPLY 12V d c or a c mains HIGH performance amateur band communi A cations receiver is necessarily rather complex and usually expensive mainly because of the use of mechanical or crystal i f filters and in the case of double conversion receivers crystal controlled oscillators The receiver to be described lacks little in selec tivity and stability and in the interests of economy does not use either crystal if filters or crystal controlled oscillators The selectivity is not as sharp as can be obtained with a good
268. n veneered housing M 5 5 WATT OUTPUT GARRARD 5200 Changer with low mass pick up arm and Stereo Cartridge CONTROLS TREBLE Individual Ganged controls Bass Treble Volume and Balance Printed circuit con struction employing 10 Transistors plus Diodes Output ratiug I H F M Suitable for Crystal Plek upa etc and for loudspeaker output impedances of 3 to 15 ohms For standard 200 250v A C mains operation Attractive silver finisbed metal facia plate and matching contro knobs Complete KIT of PARTS INCLUDING FULLY WIRED PRINTED CIRCUIT and comprehen sive wiring diagram and instructions 9 l 9 9 Or FACTORY BUILT in Teak veneered cabinet No leaflet supplied for this unit as illustrated 12 10 0 carr 7 9 Or dep 37 6 and 9 mthly pymts 29 6 Total 815 3 0 PACKAGE OFFER SAVE 4 approx Above Gas asseinbied in cabinet plus pair DORCHESTER LOUDSPEAKER UNITS 27 l 0 0 Carr 1 Or Deposit 5 and 9 monthly payments 7 6 Total 980 17 6 M H T R S C TFMI SOLID STATE VHF FM RADIO TUNER High sensitivity 5 A M 200 2507 A C Mains operation Sharp A M AD Rejection x Dritt tree reception X Output ample for any amplifier approx 500 m v Output for feeding Stereo Multiplexer Tuner head using silicon Planar Transistors Designed for standard 80 ohm co axisl cm input Visually ma
269. nce Adjustable externally up to 25M ohms Circuit Description The first three transistors are used in the pre amp and the remaining 10 in the power amplifier Class AB output is used with closely controlled quiescent current which is independent of tem perature Generous negative feedback is used round both sections and the amplifier is com pletely free from crossover distortion at all supply voltages making battery operation eminently satisfactory Applications Each 1C 10 is sold with a very comprehensive manual giving circuit and wiring diagrams for a large number of applications in addition to high fidelity These include stabilised power supplies oscillators etc The pre amp section can be used as an RF or iF amplifier without any additional transistors M ine ee r M a aa M To Sinclair Radionics Ltd 22 Newmarket Please send es for which I enclose cash cheque money order Me Vect ME PW 12A rae Ghee ek ee Se Se NAME _JADDRESS The Sinclair 1C 10 s the world s first monolithic integrated circuit high fidelity power amplifier and pre amplifier The circuit itself a chip of silicon only a twehtieth of an inch square by one hundredth of an inch thick has 5 watts R M S output 10w peak It contains 13 transistors including two power types 2 diodes 1 zener diode and 18 resistors formed simultaneously in the silicon by a series of diffusions The chip ts encapsulat
270. nd U S Governments The ban on transmissions was lifted on October Ist 1919 and very shortly afterwards 8XK was back on the air incorporating all the advances made during the War making it an extremely well equipped station for the times On the 17th of the same month Dr Conrad M Picture taken during the first broadcast of KDKA became bored with continually speaking into the microphone and to enable him to make adjustments on his equipment while it was operating he placed the microphone near his gramophone During the next few days he made considerable use of this trick and was amazed to find that listeners began writing in to ask him to play a particular record to convince sceptics that music could be transmitted over the radio The demand however became so heavy that Dr Conrad had to stop playing individual requests and 673 instead went over to broadcasting gramophone records over the station for two hours every Wednesday and Saturday Dr Conrad s use of the term broadcast to describe these transmissions is the first recorded use of the word With four hours a week of transmission time to fill the supply of records was soon exhausted and a local music store agreed to supply the records as long as Dr Conrad agreed to announce where they Gus be bought and so the first commercial was Tn The popularity of these programmes grew rapidly and from time to time live singers and bands were included in the program
271. ndic Size 9 x 7 x din approx Easy to follow inatructions and diagrams make the Roamer 7 a pleasure to build Parts price list and easy build plans 3 FREE with parta Persona Earpiece with switched socket for private listening 5 extra inserts Bize 9 x 5 x 2jin approx Tunable on Medium and Long Waves three Short Waves and Trawler Band Sensitive ferrite rod aerial for M W and L W Telescopic aerlal for Short Waves Eight improved type transistors plus 3 diodes Push pull output Battery economiser switch for extended battery life Ample power to drive a larger speaker Parts price liat and easy build plans 5 FREE with parts Earpiece with switched socket for private listening 6 extra Total building costs 5 19 6 Total building costs P amp P 5 6 transona five MEDIUM WAVE LONG WAVE AND TRAWLER BAND PORTABLE WITH SPEAKER pocket five MEDIUM WAVE LONG WAVE AND TRAWLER BAND PORTABLE WITH SPEAKER Attractive black and gold case Size 5 x 1j x Spin Tunable over both Medium and Long Waves with extended M W band for easier tuning of Luxem bourg etc 7 stages 5 transistors and 2 diodes supersensitive ferrite rod aerial fine tone moving coil speaker Easy build plans and parts price list 1 6 FREE with parts Attractive case wlth red speaker grille Bize 64 x 4j x Lin 7 stage d transistors and 2 diodes ferrite rod aerial tuning condenser volume control fine ton
272. ng Money back guarantee Makes exciting Christmas Present Christmas present Have alithe pleasure of making it yourself finish with an exeiting gift tor someone Money back quarantee READ PEOPLE S MINDS TEST THEIR NERVES EAVESDROP ON THE EXCITING BEAT THEM AT CARDS TEST THEIR MEN WORLD OF AIRCRAFT COM TAL ABILITY ETC WITH THIS ASTONISHING Make this an exciting ELECTRONIC MUNICATIONS JUST OUT V H F Christmas BRAIN BOX AIRCRAFT BAND CONVERTER 1t you ve seen a giant computor on show at an electronics exhibition you will have seen people of all ages queueing to pit their abilities against the giant electronic brain There is a tremendous fascination that attracts ordinary people and professional engineers alike vo electronic games of skill chance and mystery With this Brain box you will be able to perform mind boggling feate THE MIND READING DEVICE will make people swear you have telepathic powers THE ONLY AMAZING CARD TRICK UNIT completely mystifies and baffles from one to six people 57 6 You correctly guess the two cards each person a ce Mbny thousands of v h t Aircraft Band Converters now selling in U S A Listen in to AIRLINES PRIVATE PLANES JETPLANES Eavesdrop on exciting crosstalk between pilots ground approach ground control airport tower Hear for yourself the disciplined voices hiding tenseness on talk downs Be with them when they have to take nerve ripping decision
273. nge and special offers sent if requested with all orders or free for S A E Post free overseas This advertisement cancels all previous ones and lists supplied prior to October 30th 1970 FELSTEAD ELECTRONICS LONGLEY LANE GATLEY CHEADLE CHESHIRE SK8 4EE TERMS Cash with order oniy No C O D or caller service Post packing and insurance charges are shown in brackets after all items Regret orders under 5 plus carriage cannot be accepted Minimum charge of 1 Charges apply to G B and Eire only overseas orders welcome 8 4 F please for ali enquiries otherwise regret cannot be replied to the whole system resonated against earth with a suitable tuning unit This applies equally well to almost any aerial system of course 4 Bamboo pole Three vertical PN radiators taped to aci bamboo pole lt N Preferably k A we at 20m d E Pd n ut Pss Fig 9 Construction of a ground plane aerial for 10 15 20m If TVI is a problem the use of open wire feeders or a long wire with a tuning unit should be avoided Rather a low impedance coaxial feeder should be used together with a balun transformer in order to reduce the radiation from the feeder A balun can be made quite easily and cheaply and it will be effective over all the h f bands See RSGB Radio Communications Handbook p 13 30 02 ed 34 ft open wire or 29ft6in of 300 ohm feeder 72 ohm coaxial feeder
274. ngements of the ics will suggest suitable layouts and provided component leads are kept short there should be no stability problems The circuits can be wired up conveniently on a small piece of drilled paxolin sheet or Veroboard and put in a metal lozenge or tobacco box for screening The screens of the input and output leads and the power supply earth should be connected to the metal box ideally at the same point The author s preference is to connect the i c in dead insect fashion i e on its back with the pins sticking up It is then possible to desolder the pins one by one at a later date and remove the i c intact continued on page 651 O tol6V QC supply 641 gor AUDI w NISUAL Biene ae NS n T CONTINUITY TESTER M A SPARKS WS only a few points have to be checked Wt continuity an ordinary ohm meter is as convenient as any instrument to use But if a large number of continuity tests have to be made then the continued looking from test points to meter scale and back again can become rather tedious Sometimes too it is useful to be able to make continuity tests in a situation where a conventional meter would be inconvenient or even dangerous at the top of an aerial mast for example The unit to be described gives both an audible and visual indication of continuity between two points and will also give some indication of intermittent contacts and resist ances in circuit up to
275. nglish at 2110 21440 HCJB Quito Ecuador in English at 2055 21650 Radio Nederland Bonaire in English at 2030 Roy Patrick of Derby has sent in some more interesting items including SOUTH KOREA The Voice of Free Korea in Seoul has been heard in English at 0900 on the frequency of 9646kHz SYRIA Radio Damascus is now on 9670 and the frequency of 15165 has been dropped DXing Tips Now that the winter season is with us once again I have decided to give some hints about the tricks of the trade to help newcomers to become better DXers The subject for this month is the identification of stations using languages other than English 1 have noticed that the majority of reports to this page concern broadcasts in English whereas the most interesting stations use other languages It is easier to catch the name of a station if one knows the words which precede the name In English the most frequently used expressions are This is You are tuned to You are listening to In Spanish we have Esta es Aqu Habla In Portuguese Aqui Fala Fala vos In French Ici Vous coutez Vous tes a l coute In Italian Qui Transmette Questa In German Hier ist Hier spricht In Russian Govorit Vy slushaite In Arabic Humna Hadha Hadihi In Standard Chinese po tien tai Cantonese bor deen toy Vietnamese Day la Thai Thini Japanese Kochirawa desu
276. nimum and inject a signal of 2050kHz and adjust TC and then TCI The chassis shown at the top of the page fits on top of the main chassis and it can clearly be seen in this photograph and the one on the facing page for maximum Inject a signal of 1800KHz tune to it adjust the cores of L3 and L4 for maximum Inject a signal of 1600kHz tune to it adjust the core of L2 to maximum Inject 1900kHz and tune to it adjust TC for maximum Repeat these two last adjustments until no further improvement is obtained 629 In ail of these adjustments the output from the signal generator should be kept down so that the meter reading the voltage at the a g c test point does not exceed 3V Although the use of a signal generator is strongly recommended it is possible to align the unit reasonably well without one but it will then be necessary to complete the product detector and audio amplifier The ganged tuning capacitor in the second con verter provides the main tuning for the complete components list Resistors R1 2700 R10 1kQ R19 1kQ R2 1kQ R11 27kQ R20 27kQ R3 6800 R12 15kQ R21 2 2kO R4 6800 R13 2700 R22 6 8kQ R5 33kO R14 1kQ R23 10kO0 R6 1000 R15 33kQ R24 10kQ R7 39kQ R16 33kQ R25 6800 R8 22k0 R17 15kQ R26 2700 R9 2700 R18 39k All resistors W 10 VR1 10kQ potentiometer linear Capacitors C1 0 01nF ceramic C16 8uF 12VWielec C2 150pF 5 poly C17 O5pF C3 0 01uF ceramic C18 0 1uF ceramic C4 0 01uF ceramic C
277. ning dial and on off switching by means of earpiece plug Price Available in kit form complete with earpiece case instructions and supply of solder in fitted pack 49 6 Ready built tested and guaranteed 59 6 Sinclair Radionics Ltd 22 Newmarket Road Cambridge Telephone 0223 52731 683 SHORT WAVE H A s KITS WORLD WIDE RECEPTION Ys amp E 4 PRN a Lm oc Famous for over 35 years for 8hort Wave Equip ment of quality H A C were the Original suppliers of Short Wave Receiver Kits for the amateur constructor Over 10 000 eatisfled eustomers including Technical Colleges Hos pitais Public Schools R A F Army Hams etc NEW DI RECEIVER Improved one valve model DX mark 2 Complete kit price 68 post amp packing 4 Customer writes ustralia India and America at loud volume I am 14 years of age and have Jogged over 130 stations plus countless Amateurs from all over the world Send 8 A E for test report This kit contains all genuine short wave com ponents drilled chassis valve accessories and full instructions Ready to assemble and of course aa all our producta tully guaranteed Full range of other 8 W kits including the famous model K and K plus illustrated amp bove Alt orders despatched by return Mail order only Bend now for free descriptive catalogue amp order form H A C SHORT WAVE PRODUCTS 29 Old Bond Street London W I N
278. now proceed as in Fig 4 The tag strip has 16 tags mounting lugs being left only at each end the remainder being cut off The strip is mounted by soldering each end lug to the chassis When completed the unit should be connected to a 9V supply and the voltages checked against Table 1 Alignment Alignment can be carried out at this stage or if audible results are required can wait until the product detector and a f amplifier are completed Connect a voltmeter between the a g c test point and chassis and a signal generator via an isolating capacitor 0 01F to the base of Tr2 and turn VRI to maximum Inject an unmodulated signal of 470kHz and adjust ifts in the order if t 4 to if t 1 for maximum reading on the meter Reduce the output from the signal generator until the meter reads about 3V and again peak the i f t s for maximum Repeat until no improvement can be obtained and the i fs are then tuned As a guide the output from the signal generator for the final conditions above will be of the order of 1504 V Transfer the generator to the input of the receiver and inject a signal of 1450kHz Turn the ganged capacitor to maximum capacity and adjust L5 and then L2 for maximum output To do this correctly the cores must be screwed in from the top or hot end of the coil furthest from the chassis as it will be possible to tune the signal twice with L5 The correct signal is the first position Now turn the capacitor to mi
279. nt with natural solid teak surround Price 8 19 6 Micromatic Britain s smallest radio Considerably smaller than an ordinary box of matches this is a multi stage A M receiver meticulously designed to provide re markable standards of selectivity power and quality Powerful A G C is incorporated to counteract fading from distant stations bandspread at higher frequencies makes reception of Radio 1 easy at all times Vernier type tuning plus the directional pro perties of the self contained special ferrite rod aerial makes station separation very much easier than with many larger sets The plug in high fidelity type magnetic earpiece which matches exactly with the output of the Micromatic provides wonderful standards of reproduction both for speech and for music Every thing including the batteries is contained within the attractively designed case Whether you build your Micromatic or buy it ready built and tested you will find it as easy to take with you as your wristwatch and dependable under the severest listening con ditions Specifications Size 1 x 145 x 46 x 33 x 13mm Weight including 1 oz 28 35gm approx batteries Tuning Medium wave band with bandspread at higher frequency end Earpiece High fidelity magnetic type Battery Two Mallory Mercury Cells type R M 675 requirements for long working life Case Black plastic with anodised aluminium front panel spun aluminium dial Controls Tu
280. ntes CY31 T7j ECL86 8 PC97 8 OA3 2 6 0C99 15 0Cl172 7 6i2FR5 6 6 AF1I8 10 CRS3 20 10 6P23 ll 19AQ8 7 9 2001 10 DAF96 7 9 EF36 3 6 PC900 9 6 OA10 6 OC35 8 6 0C200 6 3N128 17 6 AF139 10 CR83 30 11 6 68A7 7 19G3 70 5933 22 6 pros ye EF37A Ti PCOR 6 6 OATO 2 j OCSS 8 6 OC2Ol 7 6 3N139 35 AFITR 18 8 CRS25 025 asavnT 6 6 1948 20 6057 10 DK96 7 6 EF39 6 PCC89 9 OA71 2 OC44 4 OC206 10 3N140 19 6 AFYI9 22 6 15 g 3 DES A EF40 10 POCI89 1L OA79 1 OC45 2 6 IN21_ 83 6 3N154 19 AS 26 5 6 CRS3 40 12 6 SSCI be 19H4 85 6060 7 6 DSi Hi EF4l 12 6 PCES00 18 OA81 1 6 OC70 3 IN21B 5 3N159 29 ASY28 5 6 GET103 4 OEIL He 20P4 17 6064 7i Lae 5 EF80 6 PCF80 6 6 OA200 1 9 OC 1 2 6 IN2o 12 6FR 5 7 9 BAWI9 5 6 GETllS 9 eee 9s 25L6GT is 6000 18 DAT Hia E33 9 7 PCFao 6 9 OA202 S OCT2 4 IN43 4j I9FR60 14 9 BCl07 3 6 GETII6 8 oT d 30015 8080 27 6 DM Jr EF83 6 6 PCF84 9 3 OA210 7 6 0C73 11 lINTO 4j 10D1 S BCI08 4j SD9IS 5 3 E E 30C17 16 09146 28j DYAG 6 yFag 6 3 PCF86 11 OA J1 9 6 OC75 4 6 1N702 7257 3 28303 10 BCY10 9 8D928 8 3 EP Hm once Hs 8020 85 DYE oF EF89 5 3 PCF200 15 6 OAZ900 11 OC76 5 IN746A 40094 27 6 BCY72 7 0 SD948 6 6 ON cm g n 16 9 9001 3 DYS Q0 EF9 3 PCF20l 15 8 OAZ201 10 OC81 4j series 6j3 40595 27 6 BFYo1 4 8 SD9oS 7 3 p
281. o providing wonderful reception of Medium recording and play back facilities F and Long Wave stations pius the new BATTERY ELIMINATOR t programmes froin your local VHF Btations Grey polystyrene cabinet with ailver trim and carrying handle Size 7 x 4j EA Fitted with earphone socket which can also be used tor extension speaker i Brand New in maker s cartons Complete with earphone instruction manual and equipment Sanyo Guarantee j tad oer AC mains 6 9 12v out put selector awitch and HI FI on off switch Case size 4 x 22 x 2in complete with mains lead connecting CATA LO G U E Jeads and instructions 59 6 DE NOW READY RT HAE LIST PRICE 89 5 P amp P 1 LIND AIR PRICE 69 Covers all leading makes plus rr amp Ins 35 accessories etc etc and full Enables transistor Excellent value for money stereo recorder 5 MS details of Lind Alr money saving 3 RS ae atte Per channel M i systems from 394 gns For table or wall mounting Smart two tone facility for gtereg b ou 2 E grey cases size 3 x 1 x 2 jin Complete recording and play bi Over 100 pages fully illustrated with lead staples and 9v battery 49 6 plus 8 page section of P A P amp P 3 6 equipment WHARFEDALE SPEAKER KITS NEW BRANCH NOW OPEN AT mst PRICE 89 19 94 96 Upper Parliament Street Complete with all components for building Into suitable cabinets NOTTINGHAM Unit 3 Kit 11 18 6 cach LIND AIR PRICE 89 GNS Un
282. o prepare for a recognized examination ICS can further your technical knowledge and provide the specialized training so essential to success ICS have helped thousands of ambitious men to move up into higher paid jobs they can help you too Why not fill in the coupon below and find out how Many diploma and examination courses available ineluding expert coaching for C amp G Telecommunication Techns Certs C amp G Electronic Servicing R T E B Radio T V Servicing Certificate Radio Amateurs Examination Radio operator Certs General Certificate of Education etc Now available Colour T V Servicing Examination Students coached until successful N EW sar suo RADIO COURSES Learn as you build You can learn both the theory and prac tice of valve and transistor circuits and servicing work while building your own 5 valve receiver transistor portable and high grade test instruments all under expert tuition Transistor Portable available as seperate course POST THIS COUPON TODAY for full details of ICS courses in Radio T V and Electronics pee eee we ee e e e c a e ig INTERNATIONAL CORRESPONDENCE SCHOOLS I l TINI l EST 1891 l Dept 17 Intertext House Stewart Road London S W 8 l Please send me the ICS prospectus free and without obligation l state Subject or Exam enne I l i NAME BLOCK CAPITALS PLEASE ADDRESS INTERNATIONAL CORRESPONDENCE SCHOOLS
283. o 3 ohms I drove the bulb from the secondary of the output transformer I experi mented with various bulbs and found the pre focus type gave the best performance 1 recall I used a 6V type To overcome the h f heating lag I included a battery in series with the bulb transformer secondary under running the bulb just enough to see the filament glowing The bat tery was bypassed to a f with a 254F capacitor When signals were transmitted the filament already hot was able to pass considerably more h f and over all a better performance was obtained Roger Bunney Hamp shire Musical pollution I think it s about time some thing was done about piped music and background music Music is supposed to soothe the savage breast but when one gets a juke box blaring in a pub when one is trying to talk business or has musical inducement when try ing to buy clothes and to cap it all music in the Hilton s lifts it makes one s breast all the more savage to think that some cretin somewhere has conned some morons somewhere else into thinking that this intrusion in duces sales and adds to enjoy ment M Casey London Wiring colours I am sorry about Mr Gal lacher s colour blindness but feel that this minority affliction hardly constitutes a valid argu ment against the well recognised colour coding for mains wiring red black and green He does not mention the other widespread use of green and red nam
284. ock diagram of the receiver is shown in Fig 1 with typical gains per stage Important considerations are the avoidance of interference by cross modulation and unwanted reception of signals caused by beating with oscillator harmonics These considerations call for good pre mixer selectivity and that no oscillator signal or harmonics appear in the r f circuits Also to this end the r f amplifier transistors must always operate in the linear part of their characteristic which means special methods of applying a g c These considera tions are taken care of in the design and will be enlarged on later 7OdB 40dB Product Detector Fig 1 Block diagram of the complete receiver with typical stage gains 626 aaa soit T i I i R23 i rif ar zo oli i r 1 uo oje rs Rae ty ae Pa E C27 5 1 i Zoos pot i METIG l 3 i i i t a Ve sitit ME 9V Fig 2 Circuit of the second converter i f amplifier TABLE 1 Base Emitter Collector Tri 7 15 Tr2 9 0 Tr3 8 8 Tr4 9 0 Tr5 9 0 Tr6 56 Voltages measured with a meter of 20kQ V In order to simplify construction the receiver is built up in units In the prototype all the completed units are mounted on or within a common chassis 12 x 9 x 2in made of 18 s w g aluminium A panel 12 x 44in 12 x 4 in with flange is bolted to the front to carry the scale drive and S meter This panel is mounted with the flange forward so
285. od of mastering ELECTRONICS and BUILD and USE a modern and profes sional CATHODE RAY OSCILLOSCOPE CARRY OUT OVER 40 EXPERIMENTS ON BASIC ELECTRONIC CIRCUITS AND SEE HOW THEY WORK PHOTO ELECTRIC CIRCUIT COMPUTER CIRCUIT BASIC RADIO RECEIVER ELECTRONIC SWITCH SIMPLE TRANSMITTER This new style course will enable anyone to really understand electronics by a modern practical and visual method no maths and a minimum of theory no previous knowledge required It will also enable anyone to understand how to test service and maintain all types of Electronic equipment Radio and TV receivers etc EXerring PRACTICAL f READ and DRAW and UNDERSTAND CIRCUIT DIAGRAMS INCLUDING A C EXPERIMENTS D C EXPERIMENTS SIMPLE COUNTER TIME DELAY CIRCUIT SERVICING PROCEDURES POST NOW 1 To BRITISH NATIONAL RADIO SCHOOL READING BERKS Please 1 I for send your free Brochure without obligation tO we do nof employ representatives l BROCHURE l NAMES EC o aea a Ee a e A eataa BLOCK CAPS I L or write if you prefer not to cut page l ADDRESS A E ET A ELI NE EE PLEASE p w 12 1 TOPIC OF THE MONTH What went wrong HATEVER happened to the Radio Hobbies Ex hibition asks an advertiser who has pulled out of the RSGB exhibition Other journals have posed the same sort of question and readers of Practical Wireless seem to be equally bemused And
286. of Home Study Courses and illustrated book FREE BRITISH INSTITUTE OF ENGINEERING TECHNOLOGY Dept Le Aldermaston Court Reading RG7 PF Servicing Numerical controi amp Computers Also self build kit courses valve and transistor Write for FREE prospectus and find out how ICS can help you in your career ICS DEPT 54 INTERTEXT HOUSE As duties will include the servicing of our complete range of products both valve and transistorised the successful applicant will have a good working knowledge of radio theory together with a number of years practical experience COLOUR TY SERVICING Be ready for the coming Colour TV boom Learn the techniques of servicing colour TV sets through new home study courses Specially prepared for the practical TV engineer technician and approved by leading manufacturer Full details from ICS D 562 Intertext House London S Sws or phone 01 720 1983 A M S E Elec City amp Guilds R T E B Cert Radio Amateurs Cert etc on Satisfaction or Refund terms Wide range of courses in Elec Engineering Design In M E C EJ A N C S stallation Repairs Refrigeration Elec A number of vacancies have arisen for young men between tronics Radio amp TV etc Send for full details and illustrated book FREE BRITISH INSTITUTE OF ENGINEERING TECHNOLOGY Dept 168K Aldermaston Court Reading RG7 4PF the ages of 15 and 20 years who wish to be trained as
287. of post Please state make and mode number alternative Free TV fault tracing chart or TV list on request with order Mail order only 694 TRADER SERVICE SHEETS 5 each plus postage We can supply Trader Service Sheets for most makes and types of Radios Tape Recorders and Televisions Manuals for some Cheques and open P O s returned if sheets not available OAKFIELD ENTERPRISES LIMITED 30 CRAVEN STREET STRAND LONDON WC2 Make Mode Radio TV 1970 List now available at 2 plus postage If list is required indicate with X From Address enclose remittance of and a stamped addressed envelope s a e with enquiries please MAIL ORDER ONLY February PW RADIO amp TV SERVICE SHEETS 4 S A E Service manuals 12 6d each P amp P 1 6d State make and model No to Bell s Television Service Albert Place Starbeck Harrogate Yorks RECEIVERS amp COMPONENTS A CORNUCOPIA OF COMPONENTS Scarce valve selected T V components Speakers Cabinets Computer panels long leads NOT printed circuits Transistors resistors new and recovered State require ments S A E F S for details MAIL MART 6 Eastbourne Road Pevensey Bay Sussex SUB MINIATURE RESISTORS SMALLER THAN A MATCH HEAD Microhm 1 16th Watt 5 Values from 512 to 100KQ 10d each Microhm Metal Glaze Resistors for the ultimate in D I Y miniaturisation JEF ELECTRONICS P W
288. one hair wire on up to four 7 029 cables 12 6 each DRILL CONTROLLER Blectronically changes speed from approxi mately 10 revs to maximum Full power at all speeus by finger tip control Kit includes all parts case everything and full inatructions 18 8 plus 2 6 post and insurance Or available made up 37 8 plus 2 6 post amp p BALANCED ARMATURE UNIT 500 ohm operates speaker or micro phone so useful in intercom or similar circuits 6 6 ea 3 10 0 doz 80 obm model 5 6 BATTERY OPERATED TAPE DECK With Capstan control This unit Is extremely well made and meas ures approx 6x5 x2 in deep Has three piano key type con trols tor Record Play hack and Rewind Motor is a special heavy duty type in tended ior operation off 4 5 volts Supplied complete with 2 spools ready to install Record Replayhead is the sensitive M4 type intended for use with transistor amplifier Price 78 6 Post and insurance 4 6 Unused ex equipment PROTECT VALUABLE DEVICES FROM THERMAL RUN AWAY OR OVERHEAT ING Thyristors recti fiera transistors etc which use heat sinks can easily be protected Simply make ihe contact thermostat part of the heat sink Motors and equip ment generally can also be ade quately protected by having thermostats in strategic spots on the casing Our contact thermo stat has a calibrated dial for setting between 90deg to 190deg F or with the dial removed range setting i
289. or bacakc BROADWAY ELECTRONICS US Bra Sen bei nied ttn EO Or E INERAT Nr Tooting Broadway Underground Station real bargain at 4 19 6 plus 12 9 P amp P MATCH 92 MITCHAM ROAD TOOTING BROADWAY LONDON S W 17 01 672 3984 Closed all day Wednesday ING TRANSFORMER for 15 ohms 16 post free 690 EX RENTAL TELEVISIONS TWO YEAR GUARANTEE from Russia l News Trot HI FI 223 RADIOGRAM 17 SLIMLINE 405 onl T il 10 0 Com rising 4 m 19 SLIMLINE 405 625 5 39 Gns Carriage and Insurance 30 FREE ILLUSTRATED LIST OF TELEVISIONS 17 7 19 21 23 WIDE RANGE OF MODELS SIZES AND PRICES DEMONSTRATIONS DAILY nne M M TWO YEAR GUARANTEED TUBES 100 REGUNNED Slim Line Tubes 110 17 and 19 109 6 21 and 23 129 6 Normal Tubes 70 and 90 17 99 6 2i 119 6 14 and other sizes 79 6 comparable with specifications costing around 140 tu tu sold by others in U K at 79 as recently as Sept 69 NOW unbelievable but true We are able to offer 500 only BRAND SPANKING NEW wita written 12 months guarantee for only 49 gns carriage etc 2 gns You ll never appreciate the wonderful reproduction possible trom your old stereo or mono records until you listen to them on this superb Hi Fi Audio Unit It s a breath taking experience But wait With the 6 Waveband Radio you can get thousanda of tran
290. ors plus 1 diode 4gin x 23in Fitted with pre set microphone gain control and mod filter Originally used to drive an NKT404 which drove a pair of NKT404s Supplied brand new c w circuit of complete modulator 22 6d plus 1 6 pp TRANSISTOR AUDIO AND MUTING PANELS Brand new set of 3 panels Audio panel with transistor gate originally used to drive an NKT404 output transistor 2 muting panels with Schmitt trigger circuit to operate the gate on the audio panel 8 transistors in all Supplied with full circuit 22 6d plus 2 6 pp 455Kc s FM LF PANEL Brand new but faulty 6 transistor panel usually low in gain 12 6 plus 1 6 pp HAND TELEPHONES Brand new radiotelephone type press to talk handsets 12 6 plus 1 6 pp VHF AERIAL C O RELAYS Used but OK 6 or 12v 4 plus 1 6 pp 60 UNTESTED MIXED TRANSISTORS 5 plus 1 pp 60 UNTESTED MIXED DIODES 2 6 plus 1 pp USED TESTED VALVES i2AX7 ECC83 2 6 6BJ6 1 6 6AQS EL90 2 6 ECF80 2 6AT6 1 6 ALSO VARIOUS VHF EQUIPMENT IN STOCK S A E AND 6d STAMP FOR LISTS COLIN RICHES ARTHUR DOW T 6 0 p m on November 2nd 1920 switches A were thrown in a small shack on top of the Westinghouse Company s building in Pitts burgh Pennsylvania U S A and the first broadcast was about to begin Throughout the day the Amer ican people had been to the election booths to cast their votes in the 1920 Presidential election and the broadcasting of the results had been chosen for the opening program
291. ort and at almost no cost at all the transmitter could be modified to cover at least two more bands thus permitting operation over tnuch longer periods by selection of the appropriate band that is active at the time The only other factor to be considered in going in for multiband operation is of course the aerial system but a suitable one is no more difficult to construct than the one band dipole and certainly need not deter anyone from going multiband Basically the idea is to alter the various tuned circuits in the transmitter so that they each cover more than one band either by changing the induc tance capacitance ratio of the existing circuit or by simple switching AVING seen many amateur stations over the ED 20metres 6CL6 VFO 4Ometres EF 91 BA 40 metres EF91 662 MULTIBAND ERIC DOWDESWELL G4AR With some circuits it is possible to obtain coverage of the 10 15 and 20 metre bands with a single inductor and capacitor While the L C ratio may not be the optimum on each band this is mainly a theoretical consideration that will have little effect on the practical results Grid drive to the following stage may be less than that which would be obtained with a properly designed circuit but the modern beam tetrode generally used in transmitters is very tolerant in this respect Practical Considerations Consider a relatively simple transmitter designed for single band operation on 20 metres consisting of a v
292. ost free Below 5 add 2 9 B A E with enquires please FULLY TESTED AND MARKED 3 00170 OC171 Oc200 0c201 26301 2303 2N1302 3 2N 1304 5 2N1306 7 2N1308 9 2N3819 FET 2N3844A Power Transistors 0C20 NEW TESTED amp GUARANTEED PAKS B 4 H8 4 B79 4 B81 10 B89 2 B91 8 B92 4 ACI07 ACI126 AC127 AC128 ACL76 ACY17 AF239 AF186 AF139 BC154 BC171 BC107 BC172 BC108 BF194 BF274 BFY50 BSY25 B8Y26 Bavo7 B8Y28 BSY29 H10 25 Mixed volts 14 watt Zeners Top Hat type B80 g 330 Mat series Alloy PNP Transistors 10 B83 Trans Mak 200 zc ge B84 100 Silicon Diodes DO 7 glass equiv 0A200 OA202 H15 30 B86 50 H18 8 Photo Cells Sun Batteries 3 to 5 volt 10 j 5 to 2 ma BY127 Bilicon Reca 1000 P T V 1 amp 10 Plastic Replaces the BY100 10 1N4007 Bil Rec Diodes 1 000 P I V mixed types large 10 j 1 amp Plastic Reed Switches and small BSP5 Light Sensitive Cella Light Hes 10 400Q Dark IMQ TO 10 j NKTI63 64 PNP Germ NEN Bil Trans AO6 BBX20 2N2359 j rejects NPN PNP 0 j 0 Top Hat Silicon Rectifiers 750 mA UE n icon Rectif ers 750 m 10 Bil Diodes sub min IN914 and IN916 10 types 10 0C23 OC25 OC26 0C28 OC35 OC36 AD149 AUY 10 2N3055 28034 equivalent to OC44 OC45 500 MHz 380mW GET113 Trans equiv to ACY17 to 10 B93 5 ACY21 PNP
293. otal list price 35 price 19 15 PRICE Carr 10 OFFERS GOLDRING GL69 2 fitted Goldring G800 cartridge complete with deluxe base and cover Total list price 50 16 0 PRICE 10 SINCLAIR STEREO 25 HALF PRICE OFFER Hi Fi solid state pre amplifier and control unit incorporating treble bass volume and balance coritrols Bwitched input for p u magnetic and ceramle mike and radio Will also aecept tape head Operates from 9V 12V battery 20V max 7 5mA Fre quency response 25Hz 30kHz 1dB Noise levet better than 50dB on all inputs Principally designed for use with Z12 Ampli fier but full instructions are supplied to enable it to be used with any amplifier Size 6 x 94 x 2i overall plus knobs Brusbed and polished atuminium front panel with matching knobs Supplied brand new and guaranteed witb full instructions Original price 9 19 8 OUR 99 1g ae PRICE TAPE CASSETTES Top quality in plastic library boxes C90 60 min 3 6 3 for 24 6 C60 90 min 18 6 3 for 36 120 120 min 185 3 for 43 6 Cassette Hend Cleaner 11 8 Post Extra HOSIDEN DH 025 STEREO HEADPHONES Wonderful value and excellent per formance combined Adjustable bead band 8 ohm im pedance 20 12 000 eps Complete with lead and stereo jack plug ONLY 47 6 P amp P 2 6 TELETON SAQ203E Au FREQ AMPLIFIER Solid state 10W per channel music power 6W rm inputs for mag ceramic tun
294. other amateurs he began some of the first tests on wavelengths below 100 metres then considered of little value In August 1922 8XK began relaying the programmes of KDKA and a year later all programmes were relayed on short waves and these were heard in Great Britain Conrad died in 1941 but in the intervening years did a great deal of research into f m and television Others were also working in these fields but Dr Conrad s contribution was considerable and he was the holder of innumerable patents 677 TAKE 20 JULIAN ANDERSON A series of simple transistor projects each using less than twenty components and costing less than twenty shillings to build requests for particular circuits The less serious have asked for colour TV circuits and stereo systems but the vast majority have asked for simple circuits that are functional when finished One such request from a reader in Manchester asked for a megaphone or loudhailer suitable for use with a car battery At first this seemed almost impossible bearing in mind our limitations on a maximum of twenty components and twenty shillings but after a little thought the circuit in Fig 1 was evolved Let me state straight away that the loudspeaker and the various items needed to form the cabinet and chassis are not included in the price and even so it will be a tight squeeze to stay under our price limit S es this series started we have had many THE CIRCUIT A careful study o
295. oughly recommends it it will be necessary to add a switch to bring in a separate tuned circuit for this band but this presumes that the v f o has been modified to provide output on 80 metres as previously suggested Power Amplifier If the existing output circuit of the p a is of the type shown in Fig and designed solely for 20 metres this alone is sufficient reason to adopt the pi network circuit shown in Fig 3 which provides greater attenuation of harmonics and easier matching of the load to the p a valve Where TVI is a problem this could very well be the only circuit which is acceptable The only additional component required is the loading capa citor which is usually of the broadcast receiving type and readily available Input Loading Ve Fig 3 Conventional pi network circuit for the power amplifier All that is now required to convert this circuit into multiband capability is a band switch selecting appropriate taps on the inductor A typical circuit with component values is shown in Fig 4 Output Input TED bots 6t 10 15 L 13 turns 1dia 3long Fig 4 Component values for a 10 15 20m pi network circuit using a 6146 valve 665 The r c across the output of the p a should not be omitted as it provides a d c path to earth for the aerial feeder thus discharging any static that might tend to build up on the aerial The rfc at the anode of the p a should be of the sectionalised type
296. oz 10 000 mtd 6v 5 9 each 88 0 0 doz 10 000 mtd 15v 8 8 each 4 10 0 doz 15 000 mtd 10v 10 6 each 25 0 0 doz 60 000 mtd 8v 22 each 210 0 0 doz 70 000 mtd 18v 40 each 20 0 0 doz TELESCOPIC AERIAL 4 portable car radio tranamitter Chrome pila ted six sections extends from 74 to 47in Hole in bottom for 6BA screw 7 6 KNUCKLED MODEL FOR F M 10 TOGGLE SWITCH 3 amp 250v with fixing ring 1 6 each 15 doz 0 OHM BALANCED ARMATURE EAR PIECE Usable as a microphone or loudspeaker 4 6 each 3 STAGE PERMEABILITY TUNER This Tuner la a precision instru ment made by the famous Cyldon t Company for the equally famous Radiomobiie Car Radio It is a medium wave tuner but set of longwave coils available as an extra if required with a frequency coverage 1620 Ke s 525 Kejs and intended to operate with an I F value of 470 Ke s Extremely compact size only 21 2 jins thick with reduction gear for fine tuning Snip price this month 18 6 with circuit of front end suitable for car radio or as a general purpose tuner for use with Amplifier Post free Horstmann Time and Set Switch A 15 amp Switch Just the thing if you want to come home to a warm house without it costing you a fortune You can delay the switch on time of your electric fires ete up to 14 hours from retting time or you can use the switch to give a boost period of up to 3 hours Equally suitable
297. p West Hyde Develop ments Ltd Ryefield Crescent Northwood Middx HA6 1NN NEWS NEWS NEWS 12V Iron Solderstat Ltd announce a P V C button down pack with a 12 volt HMS Series soldering iron with 15 feet of cable fitted with battery clips This specially designed solder ing iron has a consumption of only 12 watts consuming appreci ably less than parking lights A unique heatshield transit cover has been developed to allow the soldering iron to be packed away immediately after use Other accessories included are a coil of cored solder P V C insulation tape solder tags wiper pad screwdriver wire stripper and a desolder braid dispenser Recommended List Price is 57s 6d Solderstat Ltd P O Box 10 Bush Fair Harlow Essex Magnetic Mic A hand microphone has been introduced by the communica tions division of S G Brown Ltd of King George Avenue Watford Herts It can be used with both mobile equipment and for base installations Known as the Classic this lightweight instrument has a powerful magnet fitted in the grip which enables it to stick to any ferrous surface A user in a motor vehicle can place the instrument in the most convenient position on the vehicle s dashboard eliminating the need for a con ventional microphone holder Impedance at 000Hz is 3000 nominal Frequency response Rising at 10dB per decade over the range 100 2000Hz substan tiall
298. panion model for use with our control pre amp Discosound 40 or can be used with any other high quality pre amp control unit Completely built and tested on steel Chassis PRICE 49 10 0 inc P amp P DJ70S INTEGRATED MIXER AMPLIFIER One of the finest units available on the market today regardless of price The front end of the unit consists of a four channel mixer with separate inputs and volume controls plus a separate bass treble and master volume control One of the main features of this remarkable amplifier is its elaborate protection against short and open circuit and we can guarantee that it is virtually indestructible Allied to this is its very high power output 70W R M S a frequency response 30 20 000Hz 3dB that is superb and distortionthat is well below 1 even at full output The unit is suitable for use with discotheques groups P A clubs etc or anywhere that high quality high output is required Size 154in X Sin X 6in PRICE 63 0 0 inc P amp P Also available DJIOSS 30W PA Amplifier above Similar specification to PRICE 41 0 0 inc P amp P For full detoils of these and all Discosound Products write direct to DISCOSOUND 122 BALLS POND ROAD LONDON N 1 Telephone 01 254 5779 Full money back guarantee if returned within 10 days All Discosound Products are guaranteed for 12 months Demonstrations given at any time 686 SAME DAY S
299. phis 26L6 7 6 EM81 8 6 DISCOUNTS 2524 Gj EM84 7 6 10 on12 4 25Z5 8 6 EM85 11 any one type 2628 11 6 EM87 11 15 on25 FE ES ARTE RO US A T ERE any one ZENER DIODES type 400mw 3 8 to 33v 8 Large 1 5 watt 2 4 to 200v 4j Quantity 10 watt 3 9 to 100v 5 discounts on pes am TUE A Postage TRIACS Hen SC41A 100PIV 6A 19 6 Conductors BC41B 200PIV 8A 22 1 6 SC41D 400PIV 6A 27 6 Valves3 INTEGRATED CIRCUITS 1900 9 8 L914 9 9 L923 12 6 1C 10 50 BL403 49 6 MC1303 52 6 MC1304 55 PA246 52 6 CA3005 26 8 CA3011 16 6 CA3052 36 6 e G W SMITH amp Co RADIO LTD SAVE UP TO 33 5 6 OR MORE SEND S A E FOR DISCOUNT PRICE LISTS AND PACKAGE OFFERS GARRARD FULL CURRENT RANGE OFFERED BRAND NEW AT FANTASTIC SAVINGS 1026 stereo 7 10 8 6L72B 1294 19 68 40 Mk II stereo 8 8 0 AP75 16 19 6 2025T C stereo 8 17 8 SL75 25 19 6 3C00 stereo 9 19 6 BL7SB 227 19 6 8P25 Mk II 10 19 BL95B 87 10 0 SL66 11 126 470 11 211196 SL65B 1419 401 25 0 0 Carriage 7 6 extra each item TEAK PLINTHS amp PERSPEX COVERS 1 For 8P25 BL65 8L55 3000 2025 T C 2025 1000 24 10 0 9 For AP75 SL75 SL95 45 198 8 For SP25 etc to operate with lid in place 5 19 6 Carriage 7 6 extra each type Fuli range of Garrard accessories available SPECIAL Garrard SP95 MK H fitted Goldring G800 cartridge and wooden plinth and plastic cover T
300. ply met by Input offset current 0 2 0 44A batteries which will have many months useful life D C Power dissipation 300mW max Alternatively these circuits will generally be feeding a main amplifier from which power can be taken TABLE 1 The i c s used here are the Motorola MC1303P which contains two linear amplifiers and the R C A CA3048 which contains four linear amplifiers MC1303P This device forms an ideal basis for a stereo preamplifier By adding suitable feedback com ponents the two amplifiers can be given a suitable frequency response for equalisation of stereo signal sources such as magnetic pickups or tape playback heads altenatively the MCI303P can serve as a high gain low noise and low distortion preamp stage with a flat frequency response suitable for two inputs from tuner microphone electric guitar etc The equaliser circuits can be added to any valve or tran sistor amplifier as the MC1303P has a low impedance output to suit both high and low impedance amplifier inputs An output swing of up to 55V is available enough to drive almost any audio amplifier Lower distortion is obtained with smaller outputs however The MC1303P consists of two separate high gain amplifiers in a 14 lead flatpack The two amplifiers are arbitrarily labelled for left and right stereo channels in the circuit shown in Fig 1 but there is no reason why they should not be used for any pair of mono signals Only the power supply conn
301. produces very low impedance at the inverted input By bypassing pin 3 to earth through a large capacitor 50 100F for audio frequencies the feedback is removed at a f and the gain of the amplifier rises from about 16dB 6 to 57dB 700 A variable resistor of 25k in series with the capacitor can be used as a gain control over this range 4 CHANNEL AUDIO MIXER The circuit of a 4 channel active audio mixer based on the CA3048 is shown in Fig 9a Each input signal is brought through a level control VRI etc to an amplifier providing 34dB 50 gain set by the value of Rt etc The four outputs are combined by R9 etc to produce a single output the effect of these combining resistors is to reduce each channel s gain to approximately 20dB 10 As for the two channel mixers described the output loading should not be less than 10k0 Instead of mixing four mono signals the CA3048 can be used to mix two stereo signals For this double ganged potentiometers are used for VRI VR3 and VR2 VR4 and the output arrangement is modified as shown in Fig 9b Each double ganged potentiometer then gives simultaneous control of the left and right channels of one stereo signal and the maintenance of left right balance will be as good as the tracking accuracy of the potentiometers used CONSTRUCTION Since each of the circuits given consists of one i c and only a handful of discrete components no firm layouts need be given The pin arra
302. put signal Carrier input Ve Signal input Bias 10 Pin 10 is connected to case Fig 1 Circuit of the MC1596G Pin 10 is adjacent to the spigot 646 Theory At this stage it is necessary to introduce a little mathematics The Fourier analysis of a square wave is a sine wave of the same frequency plus a series of sine waves whose frequencies are the odd har monics multiples of the basic sauafe wave frequency or fundamental It follows then that if the modulator circuit is followed by a filter which passes the fundamental but blocks all the harmonics the output of the complete assembly will be a sine wave whose amplitude is determined by the signal input All the applications of the MC1596G are elaborations on this theoretical scheme A concept frequently found in electronics text books enters here the idea of bandwidth Only an infinitely long series of sine waves is definitively fixed in frequency this a further conclusion from Fourier theory can be illustrated approximately as follows To determine frequency a number of sine waves must be counted and the corresponding time measured from which the Hertz number or cycles per second can be calculated The more cycles included in the count the more accurate the result will be therefore to determine the frequency with absolute accuracy zero bandwidth an infinite series is required In a modulated signal the characteristics are con stantly changin
303. r version separate base treble amp val each channel with mono stereo switch 15 extra MULLARD STEREO DO IT YOURSELF Pre amplifier EP9001 8 2 0 2 amps EP9000 2 18 0 each Power Supply EP9002 4 19 0 Contro panel 2 10 0 or the lot for 15 10 0 post paid Booklet 5 6d post 6 PUSH BUTTON STEREOGRAM CHASSIS M W 8 W 1 S W 2 V H F Gram Stereo Gram Two separate channels for Stereo gram with balance control Also operates with two speakers on Radio Chassis size 15 x 7 x in high Dial silver and black 15 x 3in 190 550M 18 51M 60 187M VHF 86 100 Mc s Valves ECC85 ECH81 EF89 2x ECL86 EM84 and Rect Price 19 19 0 carr paid With Stereo Decoder fitted 7 10 0 extra 14W MAINS GRAMOPHONE AMPLIFIERS 280 ECL82 O P Transformer 3 ohm Vol On off and Tone Control Double wound mains transformer 2 x 24 x 21in separate but wired to chassis 4 x 2 x 4iin over valves 87 6 including 5iu Speaker 55 less speaker Post paid Two less 10 BCL82 with metal rect O P Transformer for 3 ohm speaker Size 8 x 5 x 21in overall Bass treble amp vol on off on separate panel 6 x ljin with fixing holes Price 67 6 3 6 p amp p Not for low output cartridge Two less 1096 MAINS TRANSFORMERS 200 250V AC INPUT Postage Postage in brackets Out 250V at 50mA and 6 3V at 11A 10 2 6 22V at 1A 6 3V at 2A and 250V at 50mA 15 3 6 250V at 40mA
304. ransls 10 j tors P O RELAYS Various Contacts and Coil Resistances Post amp Packaging 5 8 FOR 20 ALL OUR TESTED SEMICONDUCTORS HAVE A WRITTEN GUARANTEE BEND FOR OUR FREE LISTS and CATALOGUE OF ALL OUR PRODUCTS CHECK YOUR OWN EQUIVALENT WITH OUR FREE SUBSTITUTION CHART NO CONNECTION WITH ANY OTHER FIRM MINIMUM ORDER 10j CASH WITH ORDER PLEASE Add l post and packing per order OVER SEAS ADD EXTRA POSTAGE R C A CA3048 Summary of Characteristics Type Monolithic four channel amplifier silicon epitaxial structure in standard 16 lead flatpack Each amplifier has a c and temperature compensating d c feedback Max supply voltage 25 C 16V d c Temperature range 25 C to 85 C Channel separation 1kHz gt 45dB Characteristics each channel Open loop gain a c feedback bypassed gt 500 54dB Gain with feedback 6 16dB approx D C Power dissipation 150mW TABLE 2 Ch 1 nd Inputs vx Fig 8 above Internal circuit and pin identification of the CA3048 i c 4 channel amplifier The circuit of half the device is shown the other half is similar with con nections to the pin numbers in brackets Fig 9 right a Four channel active audio 3 mixer using CA3048 b Modification for mixing two stereo signals see text amplifier a very linear frequency response and a high input imped ance of nearly 100kQ the value of 4 R3 It also
305. rd rod aerial in 30 mins Russia Africa USA Switzerland cte Experience PP3 battery No soldering thrills of world wide news sport music etc Eavesdrop on unusual broad necessary Size of detector casts Uses PP3 battery Transistorised no valves Size only 3 x 43 x 14 head 134 x 10 x 23 As tremendous demand anticipated price held to only 45 3 6 p amp p Great demand expected for all parts incl Cabinet screws instr etc Parts available separately at this remarkably low Money back guarantee price ORDER WHILE Present socks AMAZING TRANSISTORIZED ween We amps CIGARETTE RADIO instructions etc etc ONLY 47 64 6 6d Yes a perfectly ordinary packet of cigarettes But watch your friends TOTAL P amp P Telescopic astonishment on hearing its range of stations loud and clear Holds 10 BUILDING handle as illustrated 25 cigarettes yet conceals sensitive fully transitorised circuit including PRICE extra Parts available tiny battery A young boy can assemble it in under 2 hours No separately Nicely boxed soldering Only 16 connections to make ALL PARTS including 9 6 makes fantastic Christ semi conductors Simple as ABC Illustrated Plans etc ONLY 29 6 mas gift Made up looks plus 2 6 post etc Parts available separately Money pack guarantee worth 15 Money back guarantee 8 Westbourne Grove London W 2 CONCORD ELECTRONICS LTD Dept PW1 4 Nr Bayswater amp Queensway Tubes min
306. rd turntable and the staff William Thomas acted as the technician L H Rosenberg as the announcer and John Frazier and R S McClelland handled the telephone lines to the newspaper offices The chief engineer was D G Little a long standing friend of Dr Conrad Oddly enough the main force behind the project was not there on that night Fearful less the new equipment should fail Dr Conrad was standing by with his station 8XK five miles away ready to take over in the event of trouble Between the election returns and the occasional music listeners heard the same request over and over again Will anyone hearing this broadcast communicate with us as we are anxious to know how far and how well this programme is being heard The broadcast was a national sensation and newspapers all over the country carried reports on the broadcast The mailbag over the next few days was massive One of the reports came from H W Irving now transmitter supervisor of KDKA He heard the broadcast on the ship Antigone then off the coast of Virginia KDKA had a fair lead on other stations and it was not until several months later that the second station came on the air this one being WBZ in Springfield Massachusetts which made its first trans continued on page 677 ELECTRIC CLOCK WITH 25 AMP SWITCH Made by Smith s these units are eios as fitted to many top quality cookers to control the oven The clock is mains driven and re quency cont
307. ready to erect Colomor Electronics Ltd n canvas bag 4 P amp P 10j 170 GOLDHAWK ROAD LONDON W12 01 743 4946 Full List of our very large 01 j METERS stock of meters on request Tels 1 783 C698 LOW PRICE HIGH QUALITY SPEAKER SYSTEMS Evito STRE EV All cabinets are new and carefully designed acousticaily with speakers mounted on jin chipboard baffles All speakers are ex TV high quality with hi flux magnets carefully matched and tested COWDREY FIVE Specially designed pee Corner Cabinet 203 x 13 x 72 in deep CAXTON COLUMN This 2 Finished in natural teak veneers with sclumn eh Inet 234 x 5 x Stin Vynair front Fitted rubber feet Five eep finished in black or wood speaker units 15 ohms impedence handles Pipes cloth with blue or grey 15 watts 5 6 0 P amp P 11 6 ynair front Keyhole slot for wall mounting Fitted with three speaker units 9 ohms imped EARPIECES WITH CORD and 3 5mm plug ance Handles 8 watts Makes all i H x the difference in quality and vol E ERA EROR 4 2180 ohm with ume of tape recorders and record players Real bargain at 59 6d P amp P 11 each SPEAKER MATCHING TRANSFORMERS 3 7 15 ohms 8 watt 13 6 P amp P 2 6 VYNAIR Widths from 40 to 54in 15 yd off roll P amp P 1 9 yard 8 P amp P 1 9 Send 1 stamps for sampies CARTRIDGES Stereo Sonotone 9TA H C Diamond 47 6 Ronette 105 Medium Output 28 6 S106 High Outpu
308. red add 20 only 659 WELBROOK HI FI AMPLIFIER KIT During last year Welbrook introduced to the Hi Fi field their unique output stage which was a completely new break through in high fidelity Audio Design It enabled us to produce an amplifier giv ing a level of distortion at low output levels normally associated with CLASS A or truly complimentary output stages but still retaining the low relative cost and advan tages of a CLASS B quasi complimentary stage To maintain our position as a forerunner in the audio field we now introduce this amplifier in kit form Consider the following brief specification and then note the price POWER OUTPUT 10 watts R M S per channe 8 ohms T H D Typically less than 0 1 for all output levels up to 10 watts INPUTS Magnetic ceramic crystal P U Tuner Tape OUTPUTS 4 8 15 ohms Tape Output The kit consists of a fibre glass P C B 20 silicon tran sistors 12 silicon diodes approximately 140 electronic components and all materials required to complete a chassis mounted amplifier including front panel and knobs PRICE 32 0s Od Cabinet Extra Further delails and fully illus trated leaflets available Welbrook Engineering and Electronics Limited Brooks Street Hr Hillgate Stockport Ches Phone 061 480 4268 660 DIMMASWITCH WRAT ATI This is an attractive dimmer unit which fits
309. reports 20 metre sigs from AX2DD AX20Z AX3AYT AX5EJ CR6MT CR7IC CT3AN EP2DA ET3DS FG7TD HBOXJK M HK3BLD JA3XPO LUSDX MP4QBK OH NI PJ2HT PZIAC PZIDF TAIKT TF2WKI TES TU2BB VEIYY VE3FKD VP8HZ VP8KL VU2BEO VU2VAE YAIMLX YV4AU ZD7SD 4N2KO 4S7PB 5X5MP 5Z4MO 6W8DY 6Y5GA 7Z3AB 9Y4VV On 21MHz Andy hooked CE7DW CR6LC CR7IZ CT2AK CX9CO JA7BSD KSTSR KP4BBK KR6JU KV4AD LGSLG LUTSE PZIAP SVICC SV WY VE3AIU VP2MM VP2VI VP8KD VP8KL VSSRG W6MSM W7APA ZD8AB ZEIDG ZSINL 3V8AL 4N2LO 474AQj MM QO N 18 W SN2AAE 5VZWT SZ4KM 6W8AL 9GIGT M 9HICB 9J2PV 9M2VI 9Q5QR 9USDP 9VIPQ A Trelinski Warks has a Lasky s Skyrover with a b fo Hoards of G stations logged on 3 5MHz while on 14MHz CEIFF K6DXX STSAD VK9NT WB6NDC Alexander says that some of these stations were stronger than Radio 4 I don t know that callsign new country T Thornton Berks CR7OA 132ft end fed is pleased with the results of an eavesdrop on 28MHz Stations immediately responsible for causing such pleasure are CR6GA CX9CO DUIFH EA8GZ FG7XT KV4CM LUSFEH MP4BFO PY8GES TR8MC ZC4IK 4X4WP 9H1BL i S Davies S Wales Murphy B40C full wave dipole for 28MHz at 20ft claims great activity on ten metres Included in his log are CE8AA CR6FA CR7AF CX8DM CTIUN EL2AW HK3VK KG4AM KP4ATS K4EBW K8SMC LU2DEK LU7AAG PY2DSQ VE3BPX 4 WB4OSW WB60DA WSBY ZE2JO ZKS5DV ZPSGS ZSI
310. rice 18 10 0 each Available from all leading high fidelity dealers Designed and Manufactured in England by 9 metrosound Metrosound Manufacturing Co Ltd Audio Works Cartersfield Road Waltham Abbey Essex Telephone Waltham Cross 31933 609 E M I LOUDSPEAKERS MODEL 450 13j x8 elliptical with twin twee ters B ohm impedance 10 watts Brand New guaranteed Lind Air Price 79 6 P amp P 4 6 MODEL 150 13 x8 elliptieal 3 and 15 ohm impedance 10 watts Lind Air Price 59 6 P amp P 4 6 TEAK FINISH SPEAKER CABINETS Size 10 x 10 x 9 Ideal or above unita 49 6 Overload protec iion 20 000 opv AC volts 10 50 250 1 000v DC volts 5 25 125 500 2500v D C Current 0 50 uA 0 250 mA Resistance 0 60K 0 6 Meg ohm Deci hels 20 to 22dB Size of meter 4j x 3 x lin Complete with case 85 P amp P 8 6 20 000 p p v DC voltage 5 25 50 250 000 2 5 K 20 000 ohms per volt AC voltage 10 50 100 00 1000 volts 10 000 ohms per volt DC Current 0 50 uA 0 2 5 mA 0 250 mA Re tance 0 6K 0 6 Mg 300 ohm and 30K at centre scale Capacitance 10f to 001 mtd 001 uf to l uf Decibels 20 to 22dB Size 4 x 31 x lin 71 P amp P 3 6 lo iei An attractive alternative for the enthusiast prepared to assemble these excellent modules to make a stereo assembly 2 30 24 watt Power Amplifier 89 6 2 required Stereo Sixty Control Pre amplifier 29 19 6 PZ 5
311. rl and Tr2 The amplified signal across R6 is taken to the triple Darlington amplifier Tr4 Tr5 Tr6 which f provides a low impedance output at pin 1 with a voltage gain equal to RI1 R12 R10 5 14 dB Unlike the amplifiers in the MC1303P each amplifier in the CA3048 has an in built a c and d c negative feed back loop R7 R9 between the output and the inverted input Temperature compen sation for the emitter base junction of Tr3 is provided by DI The effect of this feedback is to give each Microphone level The KIT IDEA by HEATHKIT kit building is so easy the Heathkit way TRY IT FOR YOURSELF START WITH A SMALL BUT VERY USEFUL KIT THE NEW HEATHKIT BATTERY CHARGER PRICE ONLY 2 18 0 plus carr 6 POWERFUL OUTPUT UP TO 4 AMPS FULLY FUSED SOLID KNOCKABOUT CASE SAFE DOUBLE WOUND TRANSFORMER e FOR 6V OR 12V CARS e ROBUST AMMETER Here s the easy to build inexpensive kit to introduce you to kit building As well as the fun and fascination of building it yourself you get Do it Yourself savings The clear simple fully illustrated instructions make assembly foolproof This is the battery charger to keep your car battery in top working condition Hurry and make sure of your order today P S This also makes an excellent seasonal present Please send me a battery charger kit for which enclose 3 4 0 including carriage 51 128 THIS MONTHS WORKSHOP AID RESETTABLE FUSE
312. rolled so it is ex tremely accurate The two small dials enable switch on and off times to be accurately set Ideal SU for switching on tape recorders Offered at only amp traction of the regular prioe new and unused only 89 6 less than the value of the clock alone post and Insurance 2 9 FLUORESCENT CONTROL KITS Each kit comprises seven items Choke 2 tube ends starter starter holder and 2 tube clipa with wiring Instructions Suitable for norma fluorescent tubes or the new Grolux tubes for fish tanks and indoor plants Chokes are super silent mostly resin filled Kit A 15 20 w 19 6 Kit B 30 40 w 19 6 Kit C 80 w 23 6 Kit E 65 w 23 6 Kit F for 8ft 126 w tube 35 Kit MFI is for Gin Sin and 12in miniature tubes 19 6 Kit MF for 21in 13 w miniature tube 20 Postage on Kits A and B 4 6 for one or two kita then 4 6 for each two kits ordered Kits C D and E 4 6 on first kit than 3 6 for each kit ordered Kit F 6 6 than 4 6 for each kit ordered Kit MF1 3 6 on first kit then 8 6 on each two kits ordered BLANKET SWITCH Double pole with neon let luto ride so luminous in dark jdeal for dark room light or tor use with waterproof element new unc plastic case 5 8 each 3 heat model 7 6 BLANKET SIMMERSTAT Although looking like and fitted as an ordinary blanket switch this ia In fact a device for switching on for varying time periode thus giving a complete control from off to full hea
313. rom the record deck to minimise hum pickup TAPE HEAD EQUALISATION Very few commercial amplifiers or preamps provide for low level inputs from stereo ie track tape playback heads an input labelled tape is generally for medium level signals that have already been equalised in a tape recorder The circuit in Fig 5 provides NAB tape playback equalisation for either 74 or 33 inches per second playing speeds depending on the values of feedback components R4 C4 etc 637 For 14 ips speed the values given for 33 ip s are fairly satisfactory or optimum values can be found by experiment A two pole three way switch will enable the component values to be switched for different speeds on many tape decks this switch can be mechanically coupled to the deck speed selector ips sw 9s Pies sw 000 Fig 5 Equaliser for stereo tape playback TWO CHANNEL MIXERS The MC1303P can serve as an active mixer for two mono signals if the two outputs in Fig 3 are connected to potentiometers as in Fig 6 Such a circuit would be useful for mixing two microphone signals The 6 8k resistors serve to reduce inter action of the two level controls and can be increased Outputs from Fig 3 Right 6 Bk Fig 6 Additional circuitry to convert Fig 3 to an active two channel audio mixer Microphone se 1 3Vwkg cT cs Magnetic __ _ pickup Ei iad 1 3vwkg T Fig 7 Mixing preamp for d
314. rticle H N S Colborn Court Cottage Horton Nr Bristol BS17 6QR EXCHANGE Practical Wireless and Television Basic Electricity Short Wave Mag Tape Recorder Wireless World 40m transceiver b f o unit aerial tuner Morse code kit TW amplifier Grundig TK23 and Radio amp Television Servicing Vols Cummins 14 Munster Sq N W 1 INFORMATION WANTED handbook and circuit diagram for R209 Mk 2 together with info on mods A A Lightbody 42 The Uplands Harpenden Herts gen on converting the 38 set for Amateur band reception S L Lumb 4 Rydali Street Leeds 11 info or mods to the Indicator unit type 26 A Milne 67 1 Dumbryden Gardens Edinburgh EH14 2NU info on the Armstrong A10 Mk 2 amplifier and control unit P L Manley 85 Nursery Drive Banbury Oxon any info on the Reflectograph 500 tape recorder R Marks Cotswold Barnet Lane Elstree Herts COpy of fault finding chart No 1 issued with April 1968 P W S M Rashid 49 M Block 6 P E C H S Drigh Road Karachi Pakistan manual for Sony tape recorder TC777 not 777A S Coles Shattery Kingsley Avenue Camberley Surrey Circuit for Ekco RP364 record player G Davies Mochen Foch Farm Lower Mochen Nr Newport Mon NP1 8UW service manual on Philips TV model M236 805 which uses a A59 11W picture tube and works on 625 lines Looi Kok Cheow Radio Malasia Kajang Selangor jalaysia D
315. rtips 24 hours a day including ships at sea and mersages from all over the world truly nothing is secret You must hear it to believe it Superb sweet tone controlled from a whisper to a roar that will fill a hall Genuine push pull output Separate ON OFF volume and Treble Bass tone controls Press button dial illumination Take it any where runs economically on standard batteries obtainable everywhere or direct through battery eliminator from 220 240v AC mains supply Internal ferrite rod aerial plus built in telescopic aerial extending to full 8lin length It s also a fabulous CAR RADIO any speed requires no additional aerial UNIQUE Elegant Black Chrome finish case SIZE llin x 9in x 3jin overall approx Made to give years ot perfect service WRITTEN GUARANTEE manual with simple operating inatruc tions and circuit diagram ONLY 18 19 6 mains battery eliminator 20 extra POST ETC 8 6 Standard batteries 5 extra Can also be used through extension amplifier tape recorder public address on VEROBOARD the Universal Wiring Board obtainable from your local Retailer Trade enquiries to NORMAN ROSE ELECTRICAL LTD 8 St Chad s Place Gray s Inn Road London W C 1 Technical enquiries to VERO ELECTRONICS LTD Industrial Estate Chandler s Ford Hants Dp WP 104 UXBRIDGE RD SHOPERTUNITIES LTD EID facing Shepherd s Bush Green London W12 8AQ Thur 1 Fri 7 Aiso 87 High Holborn London
316. s b We cannot undertake to supply detailed information for converting war surplus equipment or to supply c rcuitry c It is usually impossible to supply information on imported domestic equipment owing to the lack of details available d We regret we are unable to answer technical queries over the telephone e It helps us if queries are clear and concise f We cannot guarantee to answer any query not accom panied by the current query coupon and a stamped addressed envelope Number 14 L A J IRELAND The Motorola MC1596G Modulator Demodulator interest to the amateur radio fraternity is the Motorola MC1596G modulator demodu lator circuit It can be applied to communications problems in particular the generation of suppressed carrier signals however it will also act as a standard A NEW special purpose ic which will be of a m modulator and in receiver circuits as a detector not to mention its possibilities in laboratory instrumentation Circuit The basic mode of operation can be deduced from the circuit diagram Fig 1 It should be remembered that in standard applications a signal of considerable amplitude is supplied as the carrier with the result that Tri Tr4 act in a switching rather than a linear mode The output is therefore the product of the signal input and a square wave of a frequency determined by the carrier signal the signal input alone determines the amplitude of the out
317. s F M tuner etc E 20 20 watts R M S stereo Two Z 30s Stereo 60 High quality ceramic or 26 18 0 51 18 9 amplifier for use with low and PZ 6 magnetic P U F M Tuner efficiency high performance Tape Deck etc speakers All dynamic speakers F 404 40 watts R M S de luxe Two Z 50s Stereo 60 As for E 32 17 6 57 17 6 stereo amplifier PZ 8 and mains transformer G Outdoor public address 2 50 Microphone up to 4 P A 5 9 6 system speakers 12V car battery with converter or 45V d c controls H Indoor P A OneZ 50 PZ 8and Microphone guitar heavy 17 8 6 mains transformer duty speakers etc controls J High pass and low pass filters A F U D E or F as above 5 19 6 lair 680 Sinclair Radionics Limited 22 Newmarket Road Cambridge Telephone 0223 52731 Z 30 amp Z 50 power amplifiers The Z 30 together with the Z 50 are both of advanced design using silicon epitaxial planar transistors to achieve unsurpassed standards of performance Total harmonic distort on is an incredibly low 0 0296 at full output and all lower outputs Whether you use the Z 30 or Z50 power amplifiers in your Project 60 system will depend on personal preference but they are the same physical size and may be used with other units in the Project 60 range equally well For operating from mains for the Z 30 use PZ5 for most domestic requirements or PZ 6 if you have very low efficiency loudspeakers For Z 50 use the PZ 8 described below
318. s 3 or 15 ohms Current production by well known British maker Now with Hiflux ceramic ferrobar magnet assembly 5 10 0 P amp P 7 6 Guitar models 25w 6 10 0 35w 8 10 0 EMI 3 in HEAVY DUTY TWEETERS Powerful ceramic magnet Available in 3 or 8 or 15 ohms 18 6 each P amp P 2 6 l2in RA TWIN CONE LOUDSPEAKER 10 watts peak handling 3 or 15 ohm 37 6 P amp P 6 35 OHM SPEAKERS 31in 14 P amp P 2 6 A MAGNAVOX DESK TYPE MOVING COIL MICROPHONE Medium imp Brand New Special Price 42 p amp p 2 SINGLE HEADPHONE With aluminium headband Approx 200 ohm 5 P amp P 1 6 BALANCED ARMATURE EARPHONE Approx 70 ohm impedance Can be used as ultra sensitive STOUKISTS OF SINCLAIR EQUIPMENT 2 30 Amplfler 89 6 p amp p 2 6 Stereo 60 Pre Amplifier 0 19 6 p amp p 5 PZ Power Supply 4 19 6 p amp p 3 6 PZ6 Power Supply 7 19 6 p amp p 3 6 1C 10 Integratee Circuit 59 6 p amp p 2 GENERAL PURPOSE HIGH STABILITY TRANSISTOR PRE AMPLIFIER For P U Tape Mike Guitar etc and suitable for use with valve or transistor equipment 9 18v battery or from H T line 200 300v Frequency response 15Hz 25KHz Gain 26dB Solid encap sulation size 1j x 12 x 1 Brand new complete with instructions Price 17 6 P amp P 2 6
319. s between 80 to 800deg F Price 10 THYRISTOR LIGHT DIMMERS Will dim incandescent lighting up to 600 watts from full brilliance to out Fitted on M K flush plate same size and fixing as standard wall ewitch so may be fitted in place of this or mount on surface Price com plete in heavy plastic box with control knob 59 6 MINIATURE WAFER SWITCHES 2 pole 2 way 4 pole 2 way 3 pole 3 wag 4 pole 3 way pole 4 way 3 pole 4 way 2 pole 6 way 1 pole 12 way All at 3 8 each 86 dozen your assortment WATERPROOF HEATING ELEMENT 26 yards lengih 70W Relt regulating temperature control 10 post frer 0 005mFd TUNING ER CONDENSER EL Proved design ideal fo straight or Oe reflex circuits 2 8 each 24 doz G Designed to operate transistor sets and amplifters Adjustable output 6v 9v 12 volta for up to 500mA class B working Takes the place of any of the following batteries PP1 PP3 PP4 PPG PP7 PP9 and others Kit comprises mains transformer rectifier smoothing and load resistor condensers and instructions Real snip at oniy 16 6 plus 3 6 postage ELECTRONICS CROYDON LTD Dept PW 266 London Rd Croydon CRO 2TH Also 102 3 Tamworth Road Croydon 675 m o TTT 6BJ6 9 6K7 1 9 787 45 20P4 20 78 5 DF92 3 6 ECF80 6 6 EM84 7 6 POCSO 10 6 PY800 8 6 UCH8l 7 VALVES 65Q74 7 ek7M 8 6 7Y4 8 6 20P5 20
320. s in emergencies Tune into the international distress frequency Covers the aircraft frequency band including HEATHROW GAT WICK LUTON RINGWAY PRESTWICK ETC ETC CLEAR AS A BELL This fantastic fully transistorised instrument can be built by anyone nine to ninety in under two hours Our design team built four everyone worked first time No knowledge of radio or electronics required No soldering necessary Fully illustrated simply worked instructions take you step by step Uses standard PP3 battery Size only 43 x 3 x 13 All you do is extend rod aerial place close to any ordinary medium wave radio even tiny portable NO CONNECTIONS WHAT has selected at random from a pack they themselves 4 shuffled THE ELECTRONICS NERVES TESTER puta your friends to a very lively test It gives out fail and finish signals the winner is the person with lowest number of fail signals Can be adjusted from the weakest to strongest person THE ELEC TRONIC MAZE tests the mental ability of the player because it uses psychology with an electronic twist to it You can change the maze pathways in seconds to prevent the maze becoming too stale after lots of use Completely safe and foolproof uses standard battery Size 18 x 12 x 6 Max You can play all these games and more beside after building the Brainbox WE GUARANTEE EVER NEEDED Use indoors or outdoors THERE WILL THAT ANYONE FROM NINE TO NINETY CAN EASILY ASSEMBLE ALL THESE PR
321. s on 6 bands Directly cali brated Variable R F at tenuator audio output Xtal socket for calibra tion 220 240V A C Brand new with instruc tions 16 Carr 7 6 Size 140 x 215 x 170 mm LELAND MODEL 27 BEAT FREQUENCY OSCILLATORS Frequency 0 20 Ke s on 2 ranges Output 500Q or 5k Q Operation 200 250V A C Supplied in perfect order 19 10 0 Carr 19 TY75 AUDIO SIGNAL GENERATOR Bine Wave 20c s to 200 kc s Square Wave 20c s to 30kc s High and low impedance output Out put variable up to 6 volta 220 240 volta A C Size 210 x 160 x 120 mm Brand new with instruc tions 18 Carr 7 6 LAFAYETTE TE 46 RESISTANCE CAPACITY ANALYSER 2 pF 2000 mFd 2 ohms 200 meg ohms Also checks impedance turns ratio insulation 200 250V A C Brand New 17 10 0 Carr 7 6 270 500 MICROAMP METER Incorporated in Radio Altitude Indicator 1D Men Idea for rev counter ete 16 8 P amp P 3 ADVANCE TEST EQUIPMENT Brand new and boxed in original sealed cartons AUDIO SIGNAL GENERATOR 31B 15 c s to 50 Ke s Bine wave Output 600 ohma or 5 obms 80 0 0 VM79 UHF MILLIVOLT METER 100 Kc s to 1 000 Mc s AC 10mV to 3v DC 10 mV to 3v Current 0 01 uA to 0 3 mA Resistance 1 ohm to 10 megohm 125 0 0 TT18 TRANSISTOR TESTER Full range of facilities for teating PNP or NPN tran sistors in or out of circuit 237 10 0 Carriage 10 per item MARCONI TF195
322. s this month owe their exis tence to either 14 or 21MHz Certainly these are nearly always the easiest bands to pick up DX although the EU stations sometimes make the going a bit rough K Hastie Roxburghshire CR100 60ft long wire Joymatch a t u had a peep at 14MHz and got HC8KKU HS3ACV HV3SJ K6GUY KJ6CF MP4BBA VE2BM 5Z4KL all s s b except the two sidebands from the HC station Twenty one megahertz was found to be harbour ing CR6FP CX4CR K7UIT OHONI WBODIR 4S7TB and 9VINR all on s s b J Moore Leicester still titivating the dial on his CR100 2 fed with 130ft of wire via an a t u man aged to bag these on 14MHz AX2AAR AX2AGN AX3JW AX4KS C3ICY CN8BG EA6BN ET3USA FM7WW HT6GAF LU2FAO OB4OS another prefix for Peru OH NK PY2DSC PY3AHJ PY7VGP TDRSR VK3AM VK3QX M VKSFM VK7AZ YSIO YViON YVIACT 5 YV5DFI ZB2A ZM4FX 4N2KO Korcula Island 4X4RW 6Y5GA 9GIBF 9Y4KR Fifteen metres gave a good account of itself where John heard CR4BB CR6GA CR6JW CR7AF CT3AS EL2BU EP2DX HK3AUE HSIABC ITISEZ P Ustica fifteen JA stations JHIJLR JRIHRX KC6RS KR6JU KS6DH LUIZE ODSEP PZIAP TI2ZALG VP8KL VP9MI VU2BEO VU2OLK WB6WQV W7HFD XW8DM ZCACB ZM6QK ZSSOE SN2AAE SR8AS 5VZWT 7Z3AB 9E3USA 9GIBF O9HIBX 9HICB 9J2PV 9VIPA A Crooks Leicester RAI PR30 45ft end fed 632 Oros have varied quite a lot this past THE AMATEUR BANDS David Gibson G3J0G
323. s to minimise crossover distortion with automatic temperature compensation to prevent thermal runaway A C and d c negative feedback from the output to the input of the i c is provided by preset potentio meter VR2 This must be adjusted to obtain half the supply voltage at the i c output pin 12 The 150 loudspeaker is fed via d c blocking capacitor Cil Overall negative feedback is taken from the speaker to Trl base by R9 and VRI to form the unusual volume control which operates as follows The arrow on VR indicates the direction of clockwise rotation When this control is set fully clockwise the slider is at earth and there is no feedback from R9 The amplifier then works at maximum gain As the control is rotated anticlockwise the amplifier gain is progressively reduced as more negative feedback is introduced from R9 into Tr base The advantage over a conventional volume control in this application is that the advantages of negative feedback namely reduced distortion and extended frequency response are gained to the maximum at all volume settings There is also an economy in components At the high volume setting used with a very weak noisy telephone signal there is little or no feedback and the resulting restricted frequency response of the unit aids intelligibility Telephone C R BRADLEY As with all Class B circuits the current consump tion of the PA234 depends on the signal level and varies widely It is ther
324. sage tape 300 Tin Standard play 1200ft cartridge is constructed of brass throughout heavily chrome 34 n Triple play 600ft Myla Acetate s 126 plated uses needle and miniature ballrace bearings both Sin Double play 1200tt Tin Standard play 1200 t coarse and fine balance adjusement ia provided The fixed head Sin Long play 9001 Acetate Mylar 26 has standard jin mounting centres and is finished in black enamel Standard play 600ft 7in Long play 1800ft Mylar 18 6 with chrome lifting spur Completely wired with ali fixing nuts and washers Arm rest Double play 1800ft Mytar 7in Double play 2400 t Mylar 2 0 also supplfed Tech details Overall length 285mm needle to pivot length 223mm in Long play 1200ft Acetate 7in Long play 1800ft Acetate 15 0 offset angle 24 overhang 10mm Requires single 7 flin dia mounting hole Standard play 900tt PVC P a P 1 extra per eal 4 a and over s Ner once ed rab LASKY PRICE 9 19 6 Post 3 6 L2 ask y Radio L2 imited 207 EDGWARE ROAD LONDON W 2 Tel 01 723327 HIGH FIDELITY AUDIO CENTRES 33 TOTTENHAM CT RO LONDON WIP SRB Ter 016362605 42 45 TOTTENHAM CT RD LONDON WIP SRO Tel 01 580 2573 Open albday Sami 6p rm Morsy tes Saturday TERETE iov tarda 22 NAND nun covssooonoa 109 FLEET STREET LONDON 0 4 Tel OF 363 9812 N8 EDGWARE ROAD LONDON W2 Vei aod rad 152 3 FLEET STREET LONDON E C4 T l U1 3532832 r
325. sbottom via Bury Lanes EXPERIMENTERS new V HF AERIAL KIT Unique push pull colour coded adjustable element system gives coverage of 2 metre Amateur band Aircraft BBC VHF FM and the new local stations plus Stereo For use in or outdoors easy to instal with universal mounting bracket and mast together with rotary ball clamp VHF boom and four elements S A E for leaflet Complete kit direct from makers or from your local dealers 52 post and packing paid TUBULAR METAL PRODUCTS 7 Lowesmoor Terrace Worcester COMPUTER PANELS 5 BC108 Diodes 4 10 American total transistors Minimum 30 Details types First grade components 3 10 6 Post 1 6 Assorted Components 7 b 20 C P J W B Radio 75 Hayfield Road Salford 6 Lancs FOR SALE SEEN MY CAT 5 000 items Mechanical amp Electrica Gear and materials S A E K R WHISTON Dept PW NEW MILLS Stockport MORSE iy H EASY rae FACT NOT FICTION If you start RIGHT you will be Teading amateur and commercial Morse within a month Normal progress to be expected Using scientifically prepared 3 speed records you automatically learn to recognise the code RHYTHM without translating You can t help it it s easy as learning a tune 18 W P M in 4 weeks guaranteed For details and course C O D ring s t d 01 660 2896 send 8d stamp for explanatory booklet to G8CHS BOX 11 45 GREEN LANE PURLEY SURREY 1925 WORKING RADIO P W
326. sh enhanced by good quality Teak cabinet P PHASE 50 P A AMPLIFIER A solid state A C mains unit for Vocal and instrumental Groups and General Public Address use 50 watts output Peak 4 High sensitivity 29 GNS X 3 30 ohms matching Recommended K 3 Separately controlled inputs Retail Price Je Freq Response 22 c p s 30 Kcs For heavy demands on power Phase 100 will provide 100 watts at music rating 4 Inputs Master volume etc 59 GNS For leaflets on the above and other models in the FAL range please send SAE to FUTURISTIC AIDS LTD 104 Henconner Lane Leeds 13 for fast easy reliable soldering Contains 5 cores of non corrosive flux instantly cleaning heavily oxidised surfaces No extra flux required THIN GAUGE SOLDER ESSENTIAL FOR soldering small components and thin wires High tin content low melting point i 60 40 alloy 170ft 22 gauge on plastic reel 3 Recommended wt retail price 15 x gf INVALUABLE FOR STRIPPING FLEX THE NEW AUTOMATIC OPENING BIB WIRE STRIPPER AND CUTTER easily 4 adjustable for all standard diameters Plastic covered handles 1 can also be used as wire cutter Recommended retail price 8 6 SAVBIT ALLOY ALSO REDUCES _ COPPER BIT WEAR Ecomically packed for general electrical and electronic soldering 75ft 18 gauge on plastic reel Recommended retail price 15
327. sim 2N1132 1oj 10 up SS each Packed with semiconductors and compo TRIACS UI3 30 PNP NPN Sil Tranaistors 06200 amp 98104 0 ADI6I NPN nents 10 boards give a guaranteed 30 VBOM 2A 6A 10A e s E 23 ADI62 PNP trans and 30 diodes Our price 10 boards TO 1 TO 66 TO 88 25 NI 2N MATCHED COMPLE 10 Plus 2 p amp p 100 14 5 22 6 r MENTARY PAIRS aor TRANSISTOR A oe gee Ge 3 SISTORS For mains Acom EQULVANT BOCK ivalent VBOM Blockingvoltage U ili ti 713 Ty driven output stages of book PESE Eu ees AMENAR and in either direction U NT i ik 19 Ampiners cand Radio details and data CODED x ecei 3 Japanese Transistors Exclusive to Bi 2N3055 115 WATT SIL C20 12 1 5 amp Silicon Rectifiers Top Hat up to 1 000 PIV 10 OUR LOWEST PRICE PAK I5 each POWER NPN G21 30 AF Germanium alloy Transistors 2G300Ser amp OC7L 10 OF 12 6 PER PAIR s OUR PRICE 12 6 EACH U23 30 Madi s like MAT Series PNP Transistors 19 Sil trans FULL RANGE OF U24 iermauiurm 1 arup Rectifiers GJM up to 300 PIV suitable for ZEXER DIODES B P E Organ VOLTAGE RANGE 2 Metal TO 16V 400mv DO 7 Case 2N2060 NPN SIL DUAL TRANS CODE D1699 TEXAS Our price 5 es 190VCB NIXIE DRIVER 0 UNIJUNCTION 10 UT46 Eqve 2N2646 Eqvt TIS43 BEN3000 5 6 EACH 25 99 5 100 UP
328. smissions from all over the world including ham radio ships at sea continental and international stations Amazing clarity of tone amp incredible station selection Just read the magnificent specification of this compact fully transistorised high quality sound reproduction equipment in matching unit form Four speed single Record Player deck lightweight arm with turnover sapphire stylus and transparent deck cover etc 164 x 12 x 62 approx Two Speaker Cabinets each 181 x 94 x 8 approx each containing 8 high efficiency unit and 3 cone tweeter Fully transistorised Tuner Amplifier 26 transistors 11 diodes 184 x 91 x 8 approx incorporating VHF FM Long Medium and 3 Short wave bands All Instantaneous Press Button top panel controls Push pull output etage Frontally controlled rotatable ferrite rod aerial internal FM aerial meter type tunthg indicator atereo balance control separate variable bass and treble controls give superb balance and tone Plus all usual extension sockets 110 127 220 240v AC All cabinets very strongly constructed with beautiful high gloss walnut polyester finish Long negotiations and a final purchase for cash made this incredible offer possible Please don t ask questions just hurry Only 500 will be Incky SPARES amp UK SERVICE CONSTANTLY AVAILABLE Only 49jgns plus carriage crating handling etc 2 gns and test on 7 days appro No more to pay U K Trade distri butors
329. sult shown in Fig 3 which can be desoldered quite easily for the component removal if this should become necessary at some later stage This is a well tried method and I hope it may help readers to make better printed circuit boards A Morgan Berkshire Born too soon I am now 71 years of age and I fear have entered my second childhood Some time ago found my old toy box with relics of my younger days and in it was a book by Maurice Child called Small Power Wireless Installations price 1s There was another book entitled Wireless Telegraphy for Amateurs by Hawgrave Graham I put the books down rested my old head in my hands and lapsed into reverie I remembered my first set built in a cigar box from instructions from the Scout Next came a more ambitious one in a Hudson soap box with sliders etc I had a fine aerial with broomsticks as spreaders and aluminium wire Alas near me lived a police sergeant and when the 1914 War broke out I was ordered to hand in the lot When 2LO came on the air I was off again Some time later I remembered an old domestic set for medium and long waves under the bench I stripped the coils out got new ones from Denco with a 3 gang 300pF capacitor and re built the chassis for long medium short and trawler reception It worked but the hum was nearly as loud as the signal Now I spend hours in my shed with this set and copies of P W wondering if TIl ever be abl
330. t Although suitable for controlling the temperature of any other appliances using up to 1 amp Listed at 27 6 each we offer these while our stocks last at only 12 6 each E 7 REED SWITCHES Glass encased switches operated by external magnet gold welded contacts We can now offer types Miniature lin long x approximately fin diameter Will make and break up to 4A up to 800 volte Price 2 each 24 dozen Standard 2in long x 3 16in diameter This will break currents of up to 1A voltages up to 250 volts Price 2 each 18 per dozen Flat Flat type 2in long just over 1 16in thick approximately iin wide The Standard Type flattened out so that it can be fitted Into a smaller space or a larger quantity may be packed into a square solenoid Rating 1 amp 200 volts Price 8j each 8 per dozen Small ceramic nagnets to operale these reed switches 1 9 each 18 dozen HIGH CAPACITY ELECTROLYTICS Brand new not ex equipment 100 mtd 25v 1 8 each 12 doz 200 mtd 25v 1 8 each 15 doz 260 mtd 50v 8 8 each 83 doz 400 mtd 40v 4 4 each 46 doz 500 mtd 12v 2 each 1 1 0 doz 500 mfr 25v 3 8 each 36 doz 500 mtd 50v 4 8 each 48 doz 500 mtd 350v 8 6 each 4 10 0 doz 1000 mtd 12v 8 each 1 10 0 doz 1000 mtd 18v 3 4 each 4 doz 1000 mtd 64v 7 4 each 80 doz 2000 mtd 25v 6 8 each 79 doz 5000 mtd 12v 4 8 each 2 8 0 d
331. t Keyhole slo at back Fitted with aot SHELLEY speaker unit nly Size 21 In P amp P 5 6 each Size ZI LEX An extremely elegant speaker system made THE of 12 mm chipboard covered with teak FIESTA leathercloth with dark i or grey Vynair front send S A E for cloth Y 59 vs This e t unique system uses threeex TV speaker P amp P 5 6 Carefully matched Brit Isles and tested Will Telephone Pick up 10 6 P amp P 1 Xtal lapel Mike 7 6 Guitar Mike 12 6 P amp P 1 FERROX RODS 6 x 4 amp in 2 9 44 x jin 2 9 P amp P 1 each FERROX RODS WITH COILS 8 x 5 in P amp P 1 each ROTARY SWITCHES 2 Pole Mains Sw 3 1 pole 12 way 2 pole 2 way 3 pole 3 way 3 pole 4 way 4 pole 3 way 3 6 each P amp P 1 TRANSISTOR SPEAKERS 8 ohm 2 in 9 6 3in 10 6 P amp P 1 6 SPEAKERS E M 1 132x8in 3 ohm 5 ohm P amp P 5 6 E M I 3in tweeter 18 6 P E MLL 134 x Bin fitted two 2iin tweeters 15 ohm 90 P amp P 5 6 E M 7 sx Sms 15 ohm Hi Fi quality 6 5 0 P amp P 5 6 E M I Crossover 18 P 1 EAGLE Crossover units 3 or 16 ohms 17 4 Fitted with 7 x 3 handles o le watts P amp P 1 6 Bakers 12 in 25 watt 8 amp 15 ohms T P amp P 5 6 9x 6in ELAC Speaker and Volume control Teak veneered ohms impedance If 18 ohm 3 0 0 56 RM 109 P amp P 5 6 SR Black Vynair 10 x TE x 34 deep 3 ohm Oreperred th
332. t 28 6 Acos GP93 1 Sapphire 37 6 GP94 1 Sapphire 39 6 GP91 Stereo Compatible High Medium or Low Out put 25 TA700 equivalent to B S R SX1M 35 Japanese equivalent to B S R TC8s 35 P amp P 1 6 ELF n exten Sion speaker of quality 9 x 51 x ADASTRA DOUBLE 5 stereo solid state amplifier housed in handsome 3 x cabinet veneered in natural teak Size 114 x 6 x 5tin 10 Transistors power 34in veneered in output 5 watts peak per channel 220 240v AC Output impedance 12 to 15 natural teak with ohms our Cowdrey speaker system eminently suitable Smart blue smart gold and brown or grey escutcheon 14 14 0 P amp P 10 6 Vynait front S ehm AAA SCOTT This efeaant tapered cabinet ane pa eee 37 6 P AP 10 x 16 x 5iin deep is attractively G rga Sin Seg finished in black cloth with striped grey Vynair front Suitable for table or for wall mounting Fitted with 13 x 8in speaker unit and volume control 3 or 15 ohms impedence please state imped ance required 4 15 0 P amp P 7 6d each Fitted with E M lI 13 x Bin speaker unit and twin tweekers 15 ohms impedence capacity 10 watts 46 extra Mono Acos GP67 2 will replace Collaro and Garrard Mono cartridges 18 6 T T C Crystal High Gain 15 B S R TC8H Jap equivalent IMP Wedge shaped exten 25 P amp P 1 6 sion speaker 7 x 6 x 4in max Covered in walnut wood grain cioth with fawn The Vynair fron
333. t connect one output to the other in any way Do not short circuit the outputs with the amplifier running and developing slider power There are fuses on 7 the power supply and the modules which will pro tect them against voltage surges and accidental overloading Do not tempt providence by poking around with a screwdriver whilst the units are running To power unit Disconnected from MU442 Signal plugs RH channe power module HOME RADIO Components LTD Dept PW 234 240 London Road Mitcham CR4 3HD Phone 01 648 8422 WAY OUT of the component finding maze It may be fun finding your way out of the maze at A 1651 Hampton Court but it s not so funny trying to locate ic and obtain just the components you need for a particu ES lar job In fact the number of problems and frustrations you can meet is quite a maze ing There is an easy way out however Simply get a copy of the Home Radio Catalogue and order whatever you need from the comfort of your easy chair This famous radio and electronic constructor s Bible lists over 8 000 items more than 1 500 of them illustrated At only 12 6d 8 6d plus 4 post amp packing it s a gift especially as each copy contains 6 vouchers each worth 1 when used as directed Once you have your Home Radio Catalogue you can make life even easier for yourself by joining our Credit Account Service Then you can order by telephone any t
334. t if is coupled to the product detector via a small capacitor C19 so that a signal of about lO0mV appears at the product detector input Tr5 is the a g c amplifier and in the absence of a signal only the voltage resulting from the potential divider R21 R22 appears on the a g c line as standing bias for Trl With the r f i f gain control at maximum R21 to earth this voltage will be 1 8 volts and is referred to as the a g c reference level In this condition Tr5 is non conducting A On receipt of a signal the rectified output from the diode in ift 4 is applied between base and emitter of Tr5 and the base will be made positive with respect to the emitter and Tr5 will conduct The increase in voltage across R21 will be propor tional to signal strength and is applied to Trl as forward a g c This reduces the gain of Trl in two ways first as the transistor is turned more into the on mode its current will increase resulting in a greater voltage drop across R2 and R3 so that with a very strong signal the voltage available across the transistor between collector and emitter will be very small At the same time the base emitter impedance becomes very low further attenuating the signal The reducing voltage at R2 serves as reverse a g c for the i f amplifier Tr3 and also for the r f stage in the pre selector The diode DI is reverse biased until the voltage on the a g c line rises when the diode will conduct attenuating the
335. t to within 4 2dB R LA A from 20Hz to 90KHz Tone Control Range Rass 134B at 60Hz Preble 14dB at 15KHz Total Dis tortion for 10 watt output lt 1 5 Signal Noise lt 60dB A O Mains 200 250V Size 124 n long 4tin deep 21in high Built and tested The Sound Fifty valve amplifier and speakers are sturdily constructed with smart housings and thoroughly tested electronics They are designed to last to withstand the knocks and bumps of life on the road Built for the small and medium sized gig they are easy to handle and quick to set up and can be relied upon to come over with all the quality and power you need Output Power 45 watts R M S Sine wave drive Frequency response 3dB points 30Hz at 18KHz Total distortion less than 2 at rated output Signal to noise ratio better than 60dB Speaker Impedance 3 8 or 15 ohms Bass Control Range 13dB at THE RELIANT SOLID STATE GENERAL PURPOSE AMPLIFIER 60Hz Treble Control Range 12dB at 10 KHz Inputs 4 inputs at SPECIFICATIONS 5mV into 470K Each pair of inputs controlled by separate volume Output 10 watts Output impedance 3 to 4 ohms control 2 inputs at 200mv into 470K a aca Anata E on OT Tone ee oe ee a TOE To protect the output valves the incorporated fail safe circuit will Feqruency Response with tone controls central Minus 3bB pointa at 20Hz and enable the amplifier to be used at half power gae 40K Hz Signal to Nolse Ratlo bett
336. table for nominal 470 k se match 3 15 Q speaker and 2 independent volume controls LF Size appox 2x1x1 Only 8 6 P amp P 2 6 and separate base and treble controle are provided giving good lift and cut Valve Ime up 2 EL84s ECC83 transformer and output trans TELESCOPIC AERIALS WITH SWIVEL JOINT Can EF86 and EZ80 rectifier Simple instruction booklet S former matched for 3 ohm be angled and rotated in any direction 6 section Lacquered 2 8 Free with parts All parts sold separately ONLY speaker Separate volume control and now with improved Brass Extends from 6in to 22tin approx Maximum 7 19 6 P amp P 8 6 Also available ready built and tested wide range tone controls giving bass and treble lift and diameter jin 5 each P amp P 1 complete with std input sockets 88 19 6 P amp P 8 6 cut Negative feedback line Output 44 watts Front eS s panel can be detached and leads extended for remote BRAND NEW MULTI RATIO MAINS TRANSFOR BRAND NEW TRANSISTOR BARGAINS GET 15 mounting of controls Complete with knobs valves etc MERS Giving 13 alternatives Primary 0 210 240v ERAT uw S NENS dE OC71 5 OC76 wired and tested for only 4 15 0 P amp P 6 inations 0 5 10 15 9095 30 35 40 i 26 ADORA 0510 15 20 25 90 35 Mov at Bet of Mullard 6 transistors OC44 2 OC43 ACIOBD HSL FOUR AMPLIFIER KIT Similar in appearance E ee M to HA34 above but employs entirely different and Dam B
337. tching our Super 156 and 30 amplifiers and of the same high standard of performance and reliability Printed circuitry A quality product at considerably lesa tban the coat of comparable units FACTORY BUILT 18 gna Or tn Teak finished cabinet as illustrated 21 gns Terms Deposit 26 1 0 amp 9 mthiy prints Qyne Total 24 19 0 STEREO VERSION 234 qns Carr 10 6 extra veneer housing 20 gns Dep 3 Gns and 9 monthly payments 47 High Grade Components Specifications comparable with unite costing considerably more TRANSISTORS 9 high quality types in each channel OUTPUT 10 Watts R M 8 continuous into 150 per channel 15 Watts R M S continuous into 3 Q INPUT SENSITIVITIES Mag P U 4 mV Ceramic P U 35 mV Tape Amp 400 mV Aux 100 mV Mic 5 mV Tape Head 2 5mV FREQUENCY RESPONSE 2 dB 10 20 000 c p s FACIA PLATE Attractive design in rigid plastic silver background black lettering Silver finish matching control knobs as available Eminently suitable for use with any make of pick up or Mic Ceramic or Magnetic Moving Coil Ribbon or Crystal currently available Superb sound output quality can be obtained by use with first rate ancillary equipment COMPLETE KIT OF PARTS Point to point wiring dia b E grams and detailed instructions TREBLE CONTROL 17 dB to 14 dB at 10 Ke s Gns Carr 15 BASS CONTROL 17
338. td 22 Sun Street Reading Berks at 7s 2s 6d post and packing 100k Fig 1 The complete circuit of the telephone amplifier Note the unusual volume control see text for explanation 649 small polythene soap box sold by most chemists The volume control a standard miniature Japanese radio type and most of the components are mounted on a small piece of Veroboard This is shaped so it wedges tightly into the smaller half of the box together with the loudspeaker and battery without any other fixing being needed The Veroboard layout is shown in Fig 2 and is not critical The components need not be so closely packed if a larger box is used and the Veroboard can be shaped to suit the box Careful soldering with a small hot iron is essential Resistors should be small 1 watt types The author chose to use a fractionally under rated electrolytic capacitor only 6 4V working for C9 as this value is available in a very small size SHE The sucker of the pickup coil should be located for best reception There are two breaks to be made in the Veroboard conductors one of which is a break between two holes These breaks can be made with a razor blade which is also useful for cutting holes in the box for the loudspeaker input socket and the protruding volume control knob The author intended to glue the i c to the Veroboard there is still room there but then succeeded in soldering it to the back of the loudspeak
339. ted complete with valves and speaker 23 0 0 plus 1 p p VHF AERIAL TUNING UNITS consisting of the following 1 1 500 micro ampmeter 1 smali 2 gang 75 PF capacitor 1 various large wattage resistors for dummy load Pair gears B N C type sockets Will tune 10 mtrs with 25 30 watts R F input Size only 51 x 4l x 5 Sealed Price 27 6 p p 5 CRYSTALS AS NEW He 6u 5 345 5 030 5 005 4 945 4 875 4 840 4 795 4 580 4 660 4 520 4 510 2 300 2 295 Kc s and 10 x J465 Ke s 10 each plus 1 6 p p SCOOP PURCHASE OF BRAND NEW CARBON RESIS TORS 10 tolerance amp watt Perferred values in packets of 10 Our price 10 per 100 19 per 200 27 per 300 500 at 42 6 Our selection p p 1 6 per 100 and 6d per extra 100 TRIMMER BARGAINS These are 10PF sub min air spaced trimmers on board with min wire ended Xtal Brand new No details Contents 12 trimmers some ceramic caps Xtal frequency 3RD overtone 249 mc a 250 Mc s 255 Mc s No choice Trimmers without Xtal 12 per doz plus 3 6 p p Trimmers with Xtal 15 per doz plus 3 6 p p Also 20 PF min brand new air spaced 10 per doz plus 3 6 p p MURPHY MOBILE MR 820 TRANS RECEIVER Low pand nat tested but complete with valves Built in speaker Less erystals anu mike 12 volt input RF output 4 6 watt 5 0 0 15 p p NEW TOGGLE SWITCHES 250 volt 3 5 amps 2 pole 2 way 12 8 dozen 2 6 post and packing SIGNAL GENERATORS OSCI
340. the circuit is unbalanced with the carrier null control a component at carrier frequency is introduced and a conventional a m signal results 8V dco For morse reception the b f o is offset from the carrier and the signal will be heard at a frequency determined by the extent of the offset As before for optimum results the b f o amplitude should be 300mV and the a m or s s b may be at any level between 5 and 500mV lt will come as something of a surprise to find that this unit is also adaptable as a f m detector In this case the i f output is applied to the carrier input of the i c the signal input is fed through a linear phase shift network which may be adapted from an old f m i t The extent of the phase shift is frequency dependent and therefore varies with the audio modulation the output of the ic will be a sum of the audio signal and a series of high frequency components which are rejected Other Uses Those interested in instrumentation will recognise in the MC1596G the essential elements of a lock in or phase sensitive amplifier widely used in research and industry to recognise and identify synchronous signals once a reference frequency is available In cases where a wideband or even a tuned amplifier is swamped with noise a lock in system is still abie to follow a signal since it switches in phase with that signal and adds the outputs with the result that the signal becomes more evident while the noise
341. the communica tion receiver that you have long been waiting for Fully transistorised and continuous coverage from 555 KhZ 3 MbZ in four bands including il luminated electronic bandspread for 160 10 metres Also incorpor ated is an internal speaker automatic noise limiter SSB AM CW Switch AVC Switch S Meter Receive and Standby Switch external socket for headphone or speaker bandspread control BFO control on off AF gain band selector antenna trimmer and RF gain The R 136 wil run off of 240v AC dry batteries or any 12v DC negative ground source PRICE 45 0 0 Modei R 135 10 WATT BUDGET STEREO ALL TRANSISTOR AMPLIFIER Model R 136 DES wie Tdeal as a second stereo system or for the newcomer to Hi Fi wno wishes to upgrade existing equipment the R 136 sounds every bit as good as it looks As well as inputs for crystal or ceramic JAcartridge the R 136 has a Stereo Tuner input which accepts the matching R 134 Stereo AM FM Tuner The Satin Finish front panel carries a stereo headphone socket as weil as volume balance tone all ganged speaker mode and selector controls Supplied complete with oiled walnut enclosure SPECIFICATION Output 10 Watta Total 5 Watts per Channel Frequency 35 18 000Hz Inputs Phono and Tuner PRICE 13 0 0 AM FM MPX STEREO TUNER Model R 134 ee Perfect Matching Unit to the R 136 Amplifier The R 134 Stereo Tuner is designed to give years of reliable performance The T
342. to control processing Regular price probably around 5 Special snip price 29 6 p amp ins 4 6 DOUBLE ENDED MAINS MOTOR On feet with holes for screw down fixing To drive models oven blower heater etc 8 6 each plus 3 6 post and in surance 6 or more post free ATLAS SLIMLINE FLUORESCENTS Fluorescent lighting units made by the famous Atlas com pany with super silent polyester filled vhoke and radio suppressed starter The tube springs in and ap vut and the whole unit is beantifully made and finished white enamel Amazingly economical Measures 2ft long Is ideal in Kitchen Bedroom Hallway Porch Loft ete Don t miss this amazing offer 39 6 with tube Assembled ready to install Postage and insurance 6 6 extra 4it twin model 59 6 post amp ins 6 6 5it twin with diffuser regular price 21 our price 10 carr amp 1 230 VOLT MAINS OPERATED KLAXON HORN This is small about 10in long but has a very piercing and effective note hence It would make good Fire Alarm or Works stop and start Siren Also useful for instance to scare birds off crops Made for the Q P O so obviously best quality Slightly used but OK 89 6 plus 1 6 p p THIS MONTH S SNIP 40 WATT 12in HI FI SPEAKER Is undoubtedly one of the finest loudspeakers that we have ever offered produced by one of the country s most famous makers It has a die cast metal frame and is strongly recommended for Hi Fi and
343. tra Bame as 4 Station Intercom for two way instant communication Ideal as Baby Alarm and Door Phone Complete with 6ft connecting wire Battery 2 6 P amp P 4 6 gt Why not boost d business effi ciency with this incredible De luxe Telephone Ampli fier Take down long telephone messages or converse without holding the handset A useful office aid On oft switch Volume Control Battery 2 6 extr amp P 3 6 Full price refunded if not satisfied in 7 days WEST LONDON DIRECT SUPPLIES PW 12 169 KENSINGTON HIGH STREET LONDON W 8 BRAND NEW AR88D COMMUNICATIONS RECEIVERS AC mains input 110 volts or 250 volts Frequency in 6 bands 535 k cs up to 32 megs output impedance 2 5 600 ohms Complete with erystal filter noise limiter B F O HF tone controls Price 80 including spare set of valves headphones and manual COMPUTER BOARDS Min 30 transistors and diodes and rea etc 10 boards at 10 plus 2 6 p p 25 boards at 22 6 plus 4 6 p p BARGAIN PARCELS 14lb at 29 plus 6 6 p p 28lb at 55 plus 12 6 p p 56lb at 90 plus 25 p p Contain pots Res Valves Diodes Tagboarda Chassis Valveholders etc Good value save 8 Lucky Dip Service FURZHILL BEAT FREQUENCY OSCILLATOR 0 10 kc s 110 250 volt Good condition complete with spares 5 10 0 plus 25 p p VHF Receiver Type 715 less crystal 60 100 Mc s can be operated on 2 or 4 meters or made tunable 12 volt input not tes
344. trip of thin aluminium 20 s w g glued along the lower edge of the panel For the original amplifier this strip was cut and polished given one coat of clear varnish and glued on with Evostik The upper section of the panel was painted matt black For its final listening tests the amplifier was used with a Lenco record transcription unit and Elac stereo magnetic cartridge radio tuner stereo output a Ferrograph Series 7 half track stereo recorder and a pair of Goodmans Magnum 15 ohm speakers The excellent performance of the amplifier did more than justice to the above signal sources and to the time and effort involved in construction a introducing MAXWELL by G8DSH I don t care how much Mr Anderson says it costs to build Fm not lending you a quid THE MW COLUMN VULTUM URING November medium wave stations in Middle East countries will be prominent in the late evening long after their normal signing off times The should be quite noticeable after 2230 hrs GMT when the band is becoming quiet This situation is caused by Ramadan which ends this year on the 29th of the month It provides the MW DXer with an opportunity to log the more difficult countries from this area while newcomers to the band should be able to hear several North Africans without difficulty Look for Oujda 593kHz Sebaa Aioun 611 and 1043 Agadir 935 Tangiers 1232 all in Morocco Ain Beida 529 Oran 548 Algiers 890 in Algeria Tunis 629
345. trnded Aluminium Front Panel Two AC Convenience Ontleis KG 375A Deluxe Solid State Auto Analyzer Kit Tune up and troubie shoot any car perform actual road testa Assembled 29 GNS Teak Case 5 extra It several testers in one do all this Set Engine Idle and Automatic Trans mission Shift Points Detect Condition of Point Surfaces Detect Distributor Wear Check Voltage and Current Regulators Check Generators for both Current and Voltage Output Find Poor or Open Earth Circuits Detect Variation in Dwell Angle Recommended List Price 23 17 6 16 GNS Assembled Price 21 GNS KG 625 Deluxe 6in Vacuum Tube Volt Meter Kit Huge Bin Meter Scale Ranges d c 0 0 5 1 5 5 15 50 150 500 1 500V full scale Accuracy 3 of full scale reading input Resistance JIM Q to 1 500V Banges a c 0 1 15 50 150 500 4 500V full scale 0 414 42 140 420 1 400 4 200 V fuli scale Accuracy 5 Frequency Response d B 30Hz to 3MHz 348 30Hz to 5MHz Ohm meter Ranges 1 1 000 10 000 ohms 0 1 10 100 1 000 M amp Battery 13V U2 Recommended List Price 24 19 6 12 GNS EG 620 as KG 625 same Ranges but diin Scale Recommended List Price 18 5 6 9 GNS WHY NOT BUY THE PAIR KG 371 Deluxe Solid State Timing Light Performance surpasses assembled units eosting much more Helps Set Ignition Timing Checks Synchronisation of Double Breaker Arms Checks for Sticking Automatic Spar
346. ug 49 6 P amp P 5j MONO HEADPHONES 2000 ohm 14 6 P amp P 2 6 STEREO STETHOSCOPE SET Low imp 25 P amp P 2 MONO BTETHOSCOPE SET Low imp 10 6 P amp P SPECIAL OFFER GARRARD SP25 MK II SINGLE RECORD PLAYER FITTED GOLDRING 850 MAG above Shure M3D Pair of Hi Fi ately PREMIER PRICE Battery operated PLINTH WITH RIGID PERSPEX COVER 6 dB Standard socket inputs output wood grain finish MONO MODEL 59 6 Total list price over 24 b PREMIER PRICE 18 Gns P amp P 10 SPECIALLY PRE STRETCHED MATERIAL TENSILISED to ensure age moisture heat cold or humidity output throughout the entire audio rai LPS 3 250 P V C 5 6 TT3 450 POLYESTER 7 6 DT3 POLYESTER 11 6 SP5 P V C 8 6 LP5 P V C 10 DT5 POLYESTER 15 TAPE SPOOLS 3 1 5 51 7 1 9 Post and Packing 3 1 5 61 1 6 le magnetic recording tape OTTENHAM COURT ROAD LOND bsolutely complete and supplied ready to plug in and play er channel with inputs for pick up tape and tuner also Balance Selector Power on off stereo mono switch d ends Size 12 x 54 X 34in high Amplifier NOW AVAILABLE MATCHING FM TUNER 21 GNS socket Attractive oiled walnut cabinet with brushed aluminium front panel List Price 28 7 0 PREMIER STEREO SYSTEM FOUR Teleton SAQ203E Amplifier as Garrard SP25 Teak base and cover
347. ully tested ready to use Type CKI A 13 5 0 P amp P 6 Portable Radio designed for world wide reception TT S PERFORMANCE with Also available Compukit Deluxe Model and Compukit 2 LC Patch probably make your present radio seem like a crystal set 39 ns RADIOS board Better than any other 8 wave radio that even they havi E E produced With optional battery eliminator for both battery Cash with order or further information from and mains use We re almost giving thein away at only 13 19 6 a mere fraction ot LI M RO SE E LE C TRO N C N PW L Ch hi even today s Russian miracle price In fact we challenge you to compare the perform y ymm es re ance and value with that of 39 gn radios You just can t lose we ll refund your money if you are not astounded Purer and sweeter tone than ever Wider band spread for absolute pin point station selection Yes the Russians have really surpassed themselves this time proving once again their fantastic ability in the fleld of elec tronics and brilliantly reflecting their advanced micro circuitry techniques in the field of space communications YOU GET THIS AMAZING SET FROM UB AT A PRICE THAT BEARS NO RELATION TO ITS TRUE VALUE Yes 8 separate wavebands including Standard Long Medinm and Short Waves to cover the entire world Uniqne side control waveband selection unit gives incredible ease of station tuning Thousands of different transmissions and stations at your finge
348. undig TK144 Grundig TK149 Grundig TK121 Grundig TK141 he Grundig TK146 Truvox R44 e vi Teleton T710 os oe Teleton 5L40 Teleton FXB 510D s Crown CTR8750 o os 59 10 39 5 44 18 49 19 57 12 54 15 59 4 68 2 34 15 37 10 62 0 32 11 ooooooo 0 ooOo0o0o0o000000000o000o000000 ooooooooooooo ooo ooooooo o ooooooooooooooooooooooooooco Cave s Cash P amp C on most units Ig 12 6 Insurance value P amp C on Tape Recorders is 17 6 P amp C on cartridge is 3 6 Prices quoted above are our sell oing to press and are Special Carriage ing prices at the time of subject to alteration E amp Charges for 48hr Delivery Services it makes SOUND SENSE buy from CAVES Price 25 8 0 5017 0 49 18 0 3210 0 2219 0 0 9 0 r 19 22 19 33 10 42 19 30 17 22 19 10 10 17 7 19 19 Ww a ec Se ocooooooooooooooooooooooncaocoooo ooooooo 42 5 48 19 45 19 49 14 51 3 45 10 30 10 32 19 52 15 24 19 2 per 10 m N a eoescocoeceoooess oo00000000000006000006000000c0o 617 A COMPLETE STEREO SYSTEM SAVE OVER 30 L amp M STEREO SYSTEM COMPRISES Rec Retail Our Price Price Garrard SP25 record player with Goldring G800 magnetic cartridge complete with plinth and cover and ready wired to 5 pin Din plug EE n E Ses
349. uning Band covers AM amp FM with a separate stereo beacon to indicate when stereo broadcasts are being received SPECIFICATION FM Frequency Rauge 88 108mHz Usable Sensitivity 181V Stereo Separation 26dB at 1kHz Image Rejection 55dB AM Frequency Range 535 1 605kHz Usable Sensitivity 280uV 4 PRICE 21 0 0 rd a c 4 WATT STEREO FM AM MPX TUNER AMPLIFIER Another Roc Exclusive offering top value for money performance the R 124 is a Stereo Tuner Amp with facilities only usually found in mush more expensive units Fea tures like separate bass and treble controls automatic frequency con trol switch and stereo headphone socket give the R 124 a price to specification ratio second to none Housed in a handsome walnit cabi net the classical low line styling of the R 124 will grace any home SPECIFICATION FM Frequency Range 88 108 MHz Usable sensitivity 20uV Rtereo Separation 26db at 1 KHz 20d Minimur Image Rejection 55 dB 9 Frequency Range 535 1605 KHz Usable Sensitivity 300uV Audio Section Total Output Power 4 Watts Phono Input 200mV at 1 megohm Tape Input 100m 100 Kohm PRICE 29 19 0 Model R 124 H P Terms available for personal callers on purchases over 30 RETURN OF POST MAIL ORDER SERVICE Dept PW Orders under 10 please add 5j post and packing Orders over 10 sent post free ROC ELECTRONICS LIMITED 193 EDGWARE ROAD LONDON W2
350. unities for yourself It will cost you a stamp to find out how we can help you Free Why not do the thing that really interests you Without losing a day s pay you could quietly turn yourself into something of an expert Complete the coupon or write if you prefer not to cut the page We ll send you full details and a FREE jllustrated book No obligation and nobody will call on you but it could be the best thing you ever did BRITISH INSTITUTE OF ENGINEERING TECHNOLOGY Dept D258 Aldermaston Court Reading RG7 4PF POST THIS COUPON TODAY NE NEM DN NR IND EN RD RD IE ERO DN UND To B LE T Dept D258 Aldermaston Court Reading RG7 4PF Please send me book and details of your Courses in B L E T IN ASSOCIATION WITH THE SCHOOL OF CAREERS ALDERMASTON COURT BERKSHIRE Published appr ximately on the 7th of each month by IPC Magazines Limited Fleetw Dunstable Beds Sole Agents for Australia and New Zealand Gordon Africa Stationery and Office Supplies Ltd Subscription rate includin PRACTICAL WIRELESS is sold subject to the following conditions otherwise disposed of by way of Trade at more than the recommended lated condition or any unauthorised cov r by way of Trade ay House Farringdon Street London written consent of the Publishers first given be lent resold hired out or that it shail not be lent resold or hired out or otherwise disposed of in a muti sing literary or pictorial matter whatsoe
351. urplus Supplies GOODMAYES Unique Radio Facade GT YARMOUTH The Record Shop HALIFAX Albert Hind Ltd HARTLEPOOL Specialist Radio HERNE BAY Purday s HUDDERSFIELD Radio Craft Ltd HULL Short Wave Newland Ave ILFORD Radio Dey Clayhall Ave IPSWICH Eagle Elect Dunslac LEICESTER S May 12 14 Church Gate FREE BROCHURE 5d STAMP OR DIRECT FROM PARTRIDGE ELECTRONICS LTD P W BROADSTAIRS KENT Tel THANET 62535 TYPE LO Z JOYMATCH New one knob joystick VFA tuner 3 kw 80 thru 10m 100W on 160m Excellent S W R all bands 7 19 6 5 6 p p LIVERPOOL Stephens James Priory Rd Super Radio Whitechapel LONDON City Radio Ealing W5 Newbury Radio Forest Gate R T amp i Ashville Rd E11 LUTON Coventry Radio Dunstable Rd NEWCASTLE LYME Sydney T Chadwick NEWCASTLE TYNE Richley amp Freeman NEWPORT MON K F Paull Dock St NEWQUAY R V Heming Ltd NORWICH Radiomatics St Benedicts St NOTTINGHAM Pete s Elect Arkwright St OLDHAM The Electronic Centre The Mumps PLYMOUTH Radioparts 5 Market Way PRESTON Croftfilm 46 Friargate ROMFORD Newbury Radio 120 North St SCARBOROUGH Derwent Rdo Hillcrest Ave SOUTHAMPTON Frank Victor Northam S SHIELDS J R Gough Elect tmeary St SUNDERLAND Red Radio Shop Crowtree Rd SWANSEA Holt High Fidelity WATEORD Davis amp Kays Woodlands Pde WESTCLIFF ON SEA Radio Constructor Co WEYMOUTH Dorset Radio Lectronic WORCESTER
352. ute ABC Cinema 679 Project 60 the world s most advanced high fidelity modules With the introduction of an entirely new and original high fidelity stereo F M tuner the Project 60 range can be said at this stage to be complete it offers the constructor a most attractive choice of modular arrange ments whereby a high fidelity system can be selected to suit the user s personal requirements Equally it is possible to use any Project 60 modules separately or partially grouped and so benefit greatly from the flexibility in use these modules afford The chart below shows some of the most popular applications for constructors to assemble The Project 60 manual free with the modules suggests others as well and its 48 pages are packed with valuable information The newtuner for example can be used with any good high fidelity system as well as Project 60 Project 60 now falls into four interdependent groups 1 The Z 30 and Z 50 amplifiers which have only 0 02 distortion at all output levels and are useful in a wide variety of other applications 2 The control units comprising the Stereo 60 preamp and control unit and the Active Filter Unit A F U with which both high pass and low pass filtering can be introduced between control unit and power amplifiers 3 The Stereo F M tuner as described opposite and 4 The power supply units PZ 5 PZ 6 and PZ 8 For most requirements when using Z 30 power ampli fiers the PZ 5 will be perf
353. ver E C 4 Tel 01 236 8080 Printed in England by Index Printers and Gotch A sia Ltd South Airica Central News Agency Ltd Rhodesia and Zambia Kingston Ltd East amp postage For one year to any part of the world 2 5s 0d 2 26 namely that it shall not without the selling price shown on the cover and or affixed to as part of any publication or adverti e HENRY S RADIO TD MAILORDER AND INDUSTRIAL SALES DEPT 303 EDGWARE ROAD LONDON W2 01 723 1008 9 ELECTRONIC COMPONENTS AND EQUIPMENT AUDIO AND TEST GEAR 356 EDGWARE ROAD LONDON W 2 TEL 01 402 4736 ELECTRONIC ORGANS PUBLIC ADDRESS j DISCOTHEQUE EQUIPMENT 309 EDGWARE ROAD LONDON W 2 TEL 01 723 6963 HIGH FIDELITY SALES AND DEMONSTRATIONS 354 EDGWARE ROAD LONDON W 2 TEL 01 402 5854 DPEN MONDAY TO SATURDAY 9AM TO 6PM THURS 9AM TO 1PM OPEN ALL DAY SATURDAY COMPLETE STEREO SYSTEM FOR 39 10 0 HENELEC 5 5 STEREO AMPLIFIER Inputs for ceramic cartridge Aux Tuner Output for 8 to I5 ohms speakers Silver with black and wood finish British made Size 122 x 31 x 64 Fitted headphone socket Complete system comprises 5 5 amplifier Garrard 3000 or model 50 with 9TAHC diamond cartridge Pair E M l lOwatt speakers twin tweeters and crossover with polished wood cabinets 18 x Il x7 Also plinth and cover COMPLETE STEREO SYSTEM Rec Price 50 10 Rec Price 50 39 10 0 AMPLIFIER ONLY 13 19 6 p p 7 6
354. viewing the event objectively we have no hesitation in declaring that to our eyes the recent RSGB show was a bit of a flop This is not a dyspeptic editorial gripe As a major ex hibitor P W has a right to be concerned not only as a participant but as a voice for those at which this exhibition is aimed It must also be made clear that we are not knocking the RSGB as such the future of amateur radio relies on a healthy prosperous and influential RSGB We do feel however that in the organisation and conception of their annual exhibition they have gone sadly adrift Falling attend ance figures and lack of stand support show this clearer than any words What has gone wrong What has caused this downhill spiral of diminishing support both by traders and visitors The reasons may be complex but no doubt one contributory cause is the problem of TVI which has resulted in most amateurs buying their equipment rather than making it This is supported by the appalling lack of support for the RSGB constructional trophies only eight entries all told and none at all for the John Rouse Trophy which is for constructional entries from the under 16 s Another contributory reason must surely be the evolution of title from the humble RSGB Exhibition to the cumbersome pompous and pretentious International Radio Engineering and Communications Exhibition Whoever thought that one up deserves an OBE for sheer effrontery But what of the future The RSG
355. w York city training board and its practical results have been one amazing success story We are proud to have been selected as the only commercial training organisation permitted to use the Eduputer in the U K Thanks to Eduputer nine out of every ten can learn to operate the most advanced computers in only four weeks Unlike Computer Programming no special educational qualifications and no maths required Just you and the incredible Eduputer Jobs galore The moment you qualify our exclusive computer appointments bureau introduces you to computer users every where with good jobs to offer up to 40 a week full time 50 a week as a temporary More than enough to go round too because 144 000 new operators will be needed over the next five years alone This is your big opportunity to get out of a rut and into the world s fastest growing industry And remember LCOT is the only commercial computer school to have Eduputer It means a lot to employers Telephone 01 437 9906 NOW Or post the coupon today for full details FREE and without obligation London Computer Operators Training Centre B31 Oxford House 9 15 Oxford Street London W 1 Telephone 01 437 9906 127 131 The Piazza Dept B32 Piccadilly Plaza Manchester 1 Telephone 061 236 2935 Please send me your free illustrated brochure on exlusive Eduputer hands on training for computer operating Name Address LJ 1 NI I p A A pol 644
356. x 7 x in 8 8 14 x 11 x Rin 14 6 ALUMINIUM PANELS 18 s w g 12 x 18in 6 6 14 x in 5 6 12 x 8in 4 6 10 x 7in 8 0 8 x Bin 2 6 6 x 4in 1 6 l Inch DIAMETER WAVE OHANGE SWITOHES 2 p 2 way or 2 p 6 way or 3 p cried esch p 12 way or 4 p 2 way or 4 p 8 way 4 6 each 1 inch DIAMETER Wavechange MAKITS 1 p lg way 9 p 6 way 3 p 4 way 4 p 3 way 6 p 2 way 1 water 12 2 water 18 8 water 24 4 water 30 5 water 36 6 water 42 TOGGLE SWITCHES sp 2 8 sp dt 8 6 dp 8 6 dp dt 4 6 WOUNDS WATT STANDARD SIZE POTS ALL PURPOSE HEADPHONES H R HEADPHONES 9000 ohms Super Sensitive 35 LOW RESISTANCE HEADPHO 8 5 ohms 89 6 DE LUXE STEREO HEADPH 8 ohms e5 THE INSTANT BULK TAPE ERASER AND RECORDING HEAD DEMAGNETISER 200 250 v A C Leaflet B A E Minimum Post and Packing 2 6 ONE 47 6 Post 2 6 RETURN OF POST DESPATCH RADIO COMPONENT SPECIALISTS List Written guarantee with every purchase Export Remit cash and extra postage Buses 133 68 pass door S R Stn Selhurst GENERAL PURPOSE TRANSISTOR PRE AMPLIFIER BRITISH MADE for Mike Tape P U Guitar Battery 9 19v or H T line 200 300v D C operation Size 19 x 11 x 1 Response 25 c p s to 25 Ks s 26db gain For use with valve or transistor equipment Full instructions supplied 7 6 Post Brand new Guaranteed Details 8 A E 2 6 NEW TUBULAR ELECTRO
357. y This magniflcent machine is unobtainable elsewhere Brand New and Fully Tested only 4 19 6 plus 10 6 postage C O D with pleasura Money back if not delighted Please send s a e for interesting illus details Dept PW STANFORD ELECTRONICS Rear Derby Road North Promenade Blackpool Lancashire LADDERS VARNISHED TIMBER LADDERS from manufacturer LOWEST PRICES anywhere 154ft ext 5 10 17ft ext 5 15 20ft ext 6 5 2lift ext 7 244ft ext 8 2 29ft ext 9 5 314ft Triple ext 11 2 6 36ft triple ext 14 10 Carr 13 6 Free Lists Also Aluminium Ext and Loft Ladders CALLERS WELCOME Dept W L S HOME SALES BALDWIN ROAD SUOUREORE WORCS Phone Stourport PADGETTS RADIO STORE OLD TOWN HALL LIVERSEDGE YORKS TEL HECKMONDWIKE 4285 AIR POSITION INDICATORS Contains gears Ball Races Dimmer units Lamps four numbered Counters 24 Volt motor etc Great interest to the model makers in good condition 15 Carriage 10 GROUND POSITION INDICATOR Contains 24 Volt Lamp Prisms mirror gears Could interest schools and model makers 15 Carriage 15 NEW BOXED UNIT TYPE 8197 Contains two Toggle D P 8 T switches also one press Toggle D P 8 T Sixteen miniature 500 Ohm Pre set Pots RX TX Switches etc 5 P P 4 6 3 per dozen Carriage paid TOGGLE SWITCHES D P B T 1 P P 9d on any Switch 1 doz Post Free Ex Units D P D T SWITCHES 1 8 PRE
358. y C3 the proportion of the output signal fed back to the invert input is approximately R2 R3 1 100 Since the open loop gain of the amplifier is very high this sets the gain of this channel at 100 at audio frequencies At higher frequencies additional feedback is provided by C4 and the gain falls off Only 0 05V r m s input is sufficient to drive either channel to full output 5V r m s beyond this distortion increases rapidly Larger inputs can be handled if the gain is reduced by reducing the values of R3 and R6 The gain can be recalculated from the relation given MAGNETIC CARTRIDGE EQUALISER The circuit in Fig 4 is a useful addition to audio amplifiers with no provision for magnetic pickups Inputs 100k Fig 3 General purpose stereo preamp with level frequency response and it also enables a record player to be improved by conversion to a magnetic pickup The feedback network R3 R4 C4 CS is chosen to give the standard RIAA LP record playback curve frequency response Gain is 34dB 50 at 1kHz For a maximum output of 5V r m s at IkHz 100mV r m s input is required and total harmonic distortion is 0 1 Noise SS Left 13V 4l Fig 4 R I A A equalised preamp for magnetic pickups is 70 dB below a 10mV input and hence the circuit is suitable for the lowest output stereo cartridges As the input impedance is high special care must be given to adequate screening of the input leads f
359. y are required since the 40 metre dipole will act as a 3 2 wavelength aerial on 15 metres There will be a slight mismatch but not enough to prevent satisfactory loading of the p a Fig 7 If the ends of the additional dipoles are tied off to the supports used for the 20m dipole the direction of maximum radiation will be the same for all three dipoles A very effective aerial often neglected is the ground plane Fig 8 which is simplicity itself to erect yet can provide very low angle radiation which is so essential for DX working It is omni directional however and so will not give any discrimination against very strong Continental stations under con ditions of short skip A multiband version of the ground plane is shown in Fig 9 y 4 Wavelength Fig 8 The ground plane aerial The four radials may be sloped down wards and may even be used as stays with a lightweight mast Provided the ground plane wires for 20 metres are fitted the others are not essential although they should be erected if possible Coaxial feeder of 500 impedance should be used and the match between the aerial and the feeder can be much improved if the ground plane wires are sloped down at about 45 degrees to the horizontal Another useful multiband aerial that can be erected and forgotten is the well tried G5RV Fig 10 While the matching to the feeder is a compro mise no trouble will be found in loading the trans mitter satisfactorily on all
360. y linear over the range 2000 14000Hz falling off rapidly thereafter Sensitivity is 85dB below IV Dyne cm typical and output for normal speech is approximately 1mV true r m s Mullard Ltd announce that Mr Stanley Mullard M B E Mil Hon C G LA FLEE who founded the company 50 years ago retired from the Board at the end of September after com pleting nearly 72 years with the electrica and electronics industry Stanley Robert Mullard was born on November Ist 1883 and was apprenticed to an electrical engineering firm at the age of 15 In 1910 he joined Ediswan Three years later he became head of their lamp laboratory and in 1915 invented the Pointolite arc lamp widely used in projection apparatus During World War I he en listed in the Engineers Battalion of the Royal Naval Division and in 1916 was commissioned in the Royal Naval Volunteer Reserve and attached to the Royal Naval Air Service As a member of a small team of scientists and technologists at H M Signal School Portsmouth he was involved with the inven tion and development of high power transmitting valves in fused silica bulbs which were urgently needed by the Navy In 1920 after his demobilisation he was invited by the Admiralty to pro duce these valves in quantity The first company to bear his name the Mullard Radio Valve Company was founded in 1920 It occupied premises rented from the Z Lamp amp Electrical Com pan
361. y of which Mullard had become managing director With the spread of radio Mullard became involved in the manufacture of small receiving valves Under the trade name The Tilley Go Torch A new product from The Tilley Lamp Company is a useful butane gas blow lamp complete with paint stripper and soldering bit attachment Called the Tilley Go Torch it operates on a Tilley Go Gas 60z disposable cartridge Made from high quality chrome plated steel brass and aluminium ORA these were soon being turned out at the rate of hun dreds a week Demand rapidly outstripped factory capacity and the firm moved to larger premises at Hammersmith And in 1923 Mullard acquired still larger accommodation at Balham By the end of 1924 production stood at 25 million valves a year In 1927 a large factory at Mitcham was purchased and this is still the main centre for silica high power transmitting valves for industrial electronic applications In 1930 Mullard reluctantly decided to relinquish his leader ship of the company He had been working at full pressure since 1910 and his doctors had warned him to ease up He has since been far from inactive He has retained his seat on the Mullard Board and has continued to participate in com pany affairs Since 1945 he has also interested himself in new horticultural and other industrial developments And he has seen the company he founded 50 years ago grow to occupy a leading positio

Download Pdf Manuals

Related Search

Related Contents

Rexel Taurus  Contract Batch Import File Layout/Format User Guide  取扱説明書 - デロンギ・ジャパン  Operating Instructions Rerailing Equipment Double  Gear Head MP1200RED mice  Ditec PASAA2  Manual de configuración del sistema  Green Terminal    gpd70 cover.qxp  

Copyright © All rights reserved. Failed to retrieve file