& SERVICE MANUAL
Contents
1. BLEND CONTROL CONNECTIONS SPEAKER STEREOPHONIC REPRODUCTION Connect of the right hand speaker to the 8 16 ohm terminal of the upper R terminals on the back of the amplifier Connect of the right hand speaker to C of the upper R terminals Connect of the left hand speaker to the 8 or 16 ohm terminal of the lower L terminals on the back of the amplifier Connect of the left hand speaker to C of the lower L terminals MONAURAL REPRODUCTION When you use an 8 ohm speaker system for mon aural reproduction connect the upper and lower 16 ohm speaker terminals of your amplifier to the terminal of the speaker Connect the upper and lower C speaker termi Fw Ww w E ee SAS a E Mi ik i EKETA dani Bas nals of your amplifier to the terminal of the speaker THREE DIMENSIONAL STEREO PHONIC REPRODUCTION Your AU 70 is equipped with a terminal for a center channel amplifier so that it can be used for three dimensional reproduction To do this connect the input terminal of a monaural amplifier Either a main or combination amplifier can be used to the pin jack of the center channel output terminal at the left of the speaker terminal board with shielded wire The center channel mixes the right and left sounds to produce the three dimensi2. 14 Watt ly Watt 14 Watt Watt lv Watt 1 Watt 1 Watt 14 Watt Watt Watt 1 Watt ls Watt 2 Watt 20Watt Watt ly Watt Watt Watt l4 Watt l4 Watt Carbon Fixed Carbon Fixed Carbon Fixed Carbon Fixed Carbon Fixed Carbon Fixed Carbon Fixed Carbon Fixed Carbon Fixed Carbon Fixed Wire Wound Wire Wound Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Wire Wound Wire Wound Carbon Carbon Carbon Carbon Carbon 2 Carbon Carbon Carbon Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed 2 2 5 5 5 5 5 5 5 5 50 Electrolytic Electrolytic Electrolytic 10 10 10 1022 10 10 10 10 10 Electrolytic Electrolytic Electrolytic Electrolytic Electrolytic Electrolytic Electrolytic mylar mylar mylar mylar mylar mylar mica mica mylar Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resisto
3. sabe 519 GAIN AND SENSITIVITY PHONO MAG 84 dB Output 20W at 1 1mV input X TAL 54 dB Output 20W at 36mV input TAPE 86 dB Output 20W at 0 9mV input WEIGHT 30 Ibs HARMONIC DISTORTION HIGH AND LOW FILTER CHARACTERISTICS Imm MIC 86 dB i T arin EERDE OS at INPUT AUX S d ag add O TT AUX TAPE MON 51 dB Output 20W at 50mV input SH B8 T 222 DISTORTION Er Bo 6OHMS gt eS Hei cogn TUNER 51 dB Output 20W at 50mV input DISTORTION 46 RESPONSE dB 5 QN RATIO r Soi etre EN SS IN RATT 52 dB at TAPE terminal 30 1 CEBBILTEEHHRIL T TONE CONTROL Type CR 100 25 50 Hz 11 to 15 dB 10 000 Hz 12 to 13 EQUALIZER Type NF TAPE NARTB 505 PHONO RIAA INPUT MAIN 26 LOAD RESISTANCE 15 OHMS ACCESSORY CIRCUITS PRESENCE CONTROL Turnover at 150 Hz DISTORTION 96 LOW FILTER 50 Hz 12 5 dB zu HIGH FILTER 10 000 Hz 13 5 dB HH LOUDNESS CONTROL 25 TAPE RECORDER PLAYBACK CONNECTION DIN TERMINAL FOR CENTER CHANNEL AMPLIFIER LEVEL METER FOR OUTPUT Three ranges of 5 10 and 25W
4. Electrolytic Electrolytic MP MP MP MP Electrolytic Electrolytic Electrolytic Electrolytic tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular terminal terminal terminal terminal C72 C73 C74 C75 C76 C7 C78 C79 Cao Cal VR VR3 VR amp VR VR VRio 13 VRi4 VRis Vi V3b V 5b V9 TRi TR T2 SD 1B SW O5 5 o b 52 0 40 nF 40 uF 200 uF 200 uF 0 005 HF 0 005 uF 50 50 uF 200 uF 200 uF 0 005 uF 0 05 uF 2 500wV 5 300w V 600WV 5 25 25 25WV 500W V 400WV 500 A Electrolytic Electrolytic lug Electrolytic lug Electrolytic lug 10 oil 10 oil Electrolytic Electralytic Electrolytic Electrolytic 9946 102 oil terminal terminal terminal terminal tubular tubular tubular tubular tubular tubular tubular tubular Variable Resistor 240 type Loudness tap 120 Volume control Tone control 8 500 2 Variable Resistor 240 type Balance control 12 7 Pre amplifier 6AN8 Phase splitter 7189A Power amplifier Power transformer Output transformer Si
5. 10 10 10 1096 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 102 10 102 102 10 10 10 10 t 102 250 l4 250K 0 250K 2 250K ly Watt 410 10 10 10 10 Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon CRSOI CRSO CRSOI CRSOI CRSOI CRSO Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resisto Resistor Resisto Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Port No KO KO 40K 40K 25KQ 25K 1 50K 50K 160 160 300 300 2 5 2 5 SKO 150K 15K 4K 0 2K 12KQ 2k 5000 7KO 7KO 7KO 7KO 6K 30 uF 30 xF 30 nF 0 06 uF 0 06 uF 0 025 0 025 uF 0 01 0 01 150 1 50pF 0 01 pF l4 Watt Watt
6. These control the tone of the left speaker BASS and 17 TREBLE for R These control the tone of the right speaker HEU cnm 6 re 2 2060 4 Loi AZ VOLUME This knob is used to control the volume of the tuner records and tapes Turn it clockwise for louder reproduction To reduce the volume turn counter clockwise SELECTOR input selector TUNER For receiving broadcasts through the tuner PHONO For playing records MIC For using a microphone TAPE HEAD For playing tapes on the tape deck directly from the tape head AUX For reproducing voice input or using the MPX adaptor 20 MODE Stereophonic monaural switch This switch is used to shift from stereo phonic to monaural reproduction or vice versa STEREO Set the switch at this position for stereo reproduction Signals fed into A come out of A s speaker and those fed into B come out of B s speaker STEREO REV This position too is for stereo reproduction But signals fed into A come out of B s speaker and those fed into B come out of A s speaker Choose this position when the right and left are reversed in reproduction L R Signals fed into L and R are blended into one L4 R in the amplifier before they come out separately from L and R Signals fed into A and B become A B in the amplifier and come out of the speakers of A and B in the form of the comb
7. 150K 2 400K 400 1 5K 1 5K 5MQ 5MQ 100K 2 100K 2 Watt Watt Watt Watt Vi Watt 14 Watt ly Watt Watt 1i Watt Watt Watt 14 Watt Watt Watt Watt Watt 14 Watt Lo Watt i Watt 14 Watt Li Watt 1 Watt 14 Watt 1 14 Watt 15 Watt PARTS LIST Momenciature 10 10 102 102 102 102 102 102 102 102 10 10 10 102 102 10 10 10 10 1022 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 102 102 10 10 10 10 10 10 10 10 10 Carbon Carbon Carbon Carbon Carbon Carbon Carbon Fixed Fixed Fixed Fixed Fixed Fixed Fixed Noise Less Noise Less Noise Less Noise Less Noise Less Carbon Carbon Fixed Fixed Noise Less Noise Less Noise Less Noise Less Noise Less Noise Less Noise Less Moise Less Carbon Carbon Fixed Fixed Noise Less Noise Less Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Carbon Enclosed in CRSO2 Enclosed in CRSO Fixed Fixed Fixed Fix
8. diode AC RMS 280V ID 500mA 60 100 C 03 1 diode AC RMS 90V ID 500mA 55 C 100 C Cartridge switch Input Selector switch IMO Variable Resistor 240 type 50KQ B Variable Resistor driver type 1000 Hum Balancer driver type Transistor 258 381 Head amplifier S3 a c 54 5 a b 56 a d 57 4 S8 a b 59 510 S11 a b 12 513a 13b 514 14b CO 2 OA 9 Mode switch Tape monitor switch Loudness switch Tone defeat switch Low filter switch High filter switch Presence switch Speaker switch Level meter control switch Power switch Level meter pilot lamp switch Level meter switch AC outlet Ge diode VD 90V ID 25mA 552 75 SCHEMATIC DIAGRAM TR TR TUNER 25B 381 2 HEAD p REC D E MON AUX H 5 Ry EARTH a RED TUNER 6 WHITE PHONO Gr site 9 MIC G o85K 24 TAPE i HEAD 6 5 MON G AUX G OL MICA MP MYLAR NOISE LESS CERAMIC Sp MAG 2 Xtal S la f INPUT SELECTOR TUNER 2 PHONO a MIC 4 TAPE 5 AUX Syla e MODE SELECTOR REVERSE i NORMAL 3 MIX R L 4 CHAN R 5 CHAN L 5 OF F ON TAPE MONITOR GANG vwa BANB uu 7189 6 CRSOI Ra 8 w 7189 28 ee 40 i um fema
9. from records made of poor material or noise due to fluorescent lamps in the case of the tuner TONE DEFEAT Turn this switch ON to open the tone control circuits Then the frequency re sponse curve of the amplifier will become perfectly flat 19 TAPE MONITOR When you make recordings with a three head tape recorder turn this switch ON to use the amplifier as a monitor Then the sounds recorded on the tape re produced while you are recording Keep this switch ON when vou play the tape on the tape recorder sure to keep the switch OFF other Wise 42 BALANCE This knob is used to adjust the balance of volume between the right and left speakers for the best stereophonic effect Make the adjustment while watching the output level meters and listening to the sounds of both speakers When the amplifier is adjusted properly vou feel as if the sound comes from point midway between the two speakers 43 BLEND This knob permits continuous shift from stereophonic to monaural reproduction Turn it counter clockwise to bring repro duction closer to monaural R L For complete monaural reproduction turn it as far counter clockwise as possible The sounds of the right and left speakers become separated when you turn the knob clockwise R and L perform their respective functions The best stereophonic effect is obtained when you turn it as far as possible BASS and 45 TREBLE for
10. monaural tuner output to the input terminal of the adaptor and connect R and L of the adaptor output terminals to R L respectively of the AUX terminals on the back of your amplifer TAPE RECORDER 1 SINGLE CONNECTION TAPE RECORDER DIN STANDARD SPECIFICATION Connect the single connection connector to the receptacle on the back of your amplifier 2 PIN JACK TAPE RECORDER Recording Connect the tape recorder input terminals to R and L or L in the case of monaural opera tion of the terminals on the back of your amplifier with shielded wires b Playback Connect the tape recorder output terminal LINE to and L or L in the case of monaural operation of the TAPE MON terminals on the back of your amplifier 3 Playing tapes on the tape deck Connect the tape deck output terminals to R and L R or L in the case of monaural opera tion of the TAPE HEAD terminals on the back of your amplifier 4 Monitoring with a three head tape re corder a Single connection tape recorder Connect the single connection plug to the receptacle on the back of your amplifier b Pin jack tape recorder Connect the tape recorder input terminals and L R or L in the case of monaural opera tion of the REC terminals back of your amplifier Also connect the tape record
11. 773 7 500503 20 C NOISE LESS Se 4 K 2 f e x 8 R 2 C 18V Mo Een L O CERAMIC la 4 B Sen 1 OFF S ab 2 TONE DEFEAT 8 58 LEFT PL RIGHT PL 1 HAG Bo 3 5 4 OFF 24V x 2 ON LOW FILT 5 co S INPUT SELECTOR ER amp x TUNER a b ae 2 N NH FILTER T no LOW 3 MIC 2 3H FIL a 4 TAPE 2 LEVEL MIDDLE 5 AUX 3 LEVEL HIGH MODE SELECTOR 7 ON PRESENCE 52 Sie LEVEL METER OFF 1 2 3 4 OFF c i NORMAL VON uns 5 o d Sra PILOTLAMP CHAN 2 OFF SPEAKER 123 4 OFF Swe LEVEL METER E 5 CHAN L 5 QN 1 2 3 5 OFF 1 2 3 5 OFF 2 TAPE MONITOR 4 UN SANSUI ELECTRIC COMPANY LIMITED Head Office 14 1 2 chome Izumi Suginami ku Tokyo Japan TEL 323 1111 Printed in Japan 1200 6
12. al negative feedback 26 dB for the first time in this class of amplifiers in Japan This makes it extremely low in distortion over the whole frequency range Total harmonic dis tortion at 1 is 0 15 At 30 a very low frequency at which it is extremely difficult to minimize harmonic distortion the distortion is limited to not more than 0 95 This is quite a feat for a 50 watt amplifier Another remarkable feature is the damping factor of 18 a figure which is lower than that of triode power tubes coupled in P P This is why bass sounds come out with such clarity NFB USED IN ALL AMPLIFIER CIRCUITS FROM PREAMP TO POWER AMPLIFIER The low distortion of the power amplifier is meaningless if the preamplifier generates distor tions Your AU 70 uses a three stage amplifier circuit in its intermediate or control amplifier unlike conventional one stage control amplifiers and has all its circuits in a single negative feed back loop These make your AU 70 free from noise and distortion SUPER PRECISION TRANSISTOR PREAMP LIFIER ELIMINATES HUM AND NOISE The exclusive Sansui four transistor preamplifier which features a transistor circuit factor of 4 as compared with conventional 5 10 and a transistor noise factor of 2 dB as compared with conven tional 5 dB eliminates hum and noise the enemy of high fidelity reproduction The amplifier has a much better S N ratio and a gain three times larger than vacuum tub
13. alancer not properly adjusted Check VR and 5 Disconnected NF resistor Check Rs and B Hum on PHONO and TAPE 1 Defective shielded wire and or wrong con Replace and connect correctly nection of record player tape recorder others Keep proper distance between audio svstem and inductor Audio system and shielded wire induced from outside 3 Residual hum of audio system connected to the unit Replace or repair A Noise on AUX and TUNER 1 Fixed resistor badly connected or touched Check Ran Ras Rea Res by another part Ra Rez Ros and Check Ceo 2 Capacitor nearly short circuited or touched by another part 3 Primary coil of output transformer nearly Check and disconnected 4 Defective tube Check Noise on PHONO and 1 resistor defective or nearly discon Check R R 2 Defective capacitor Check C C 3 Noise or bad connection of audio system Replace or repair connected to the unit 5K 5 100K 2 100K 150K 2 150K 2 170K 170K 100K 100K 15K 15K 3000 3000 15 15KO 70KO 70KO 15KO 15K 2 12K 4 12K 100 100 3KO 3KO 12KO 12KO 16KO 16 SKO 5KO SOKO 50KO 2 5 2 5 150 150K 0 100K 100K 2 150K 0
14. ality of your recordings while thev are being made RECORDING 1 Set the SELECTOR switch at the proper position according to the program source broad cast or record vou are going to record 2 Set MODE switch at STEREO for stereophonic recording at R or L for monaural recording or at L R for monaural recording of a stereophonic source 3 Prepare the tape recorder for recording 4 Operate the recorder and amplifier adjusting knobs and switches properly Amplifier adjusting knobs do not affect the level and tonal quality of recordings but only control those of the sound from the speakers When you record a broadcast or record you can obtain better results by connecting the tape recorder directly to your amplifier instead of picking up the sound from the speakers with microphones PLAYBACK 1 a Tape deck Set the SELECTOR switch at TAPE b Tape recorder set the MONITOR switch at ON 2 Set the tape recorder in the play position 3 Other adjusting knobs and switches can be used for the most satisfactory reproduction CAUTION When you use a Tape Recorder keeping the TAPE MONITOR switch at ON the MODE switch is not operative If you want to use the MODE switch connect the recorder output to the AUX pin jacks on the back of your amplifier and the MONI TOR switch at off TAPE MONITORING To use your amplifier as a moni
15. ance 50 kilo ohm crystal dynamic or velocity microphone is accept able 1 Set the SELECTOR switch at 2 Set the MODE switch at STEREO when vou use onlv one microphone for stereo phonic effect at R when vou use only one microphone for monaural reproduction or at L R when you mix two different pro _ gram sources from two microphones 3 During stereophonic operation you can use the BLEND knob for mixing purposes 4 Other adjusting knobs and switches can be used for the most satisfactory reproduction Remember that your AU 70 accepts only high impedance microphones You cannot get the best performance if vou use too long micro phone cord which causes various problems and reduces treble Your amplifier has separate tone controls for rght and left speakers You will find this feature very useful when vou use one phone for music and another for voice Further more it gives added versatility to your amplifier particularly when you record on tape what is picked up by microphones RECORD AND PLAY TAPES Your AU 70 can be used with a tape recorder for recording and playback and can also play tapes on the tape deck If you use a three head tape recorder which has separate record and playback heads you can make recordings while listening to a reproduction of the recordings In other words your amplifier can be used as monitor which lets you know the qu
16. e amplifiers EACH CHANNEL CAN BE OPERATED IN DEPENDENTLY EQUIPPED WITH TONE DEFEAT Each channel has independent tone controls for bass and treble This makes fine adjustment possible Moreover each channel is equipped with tone defeat which cancels the tone control circuits You can easily obtain a flat frequency response without causing any undulation in response or reduced gain in bass and treble as in the case of conventional mechanical control by means of a tone volume knob Therefore you can get an accurate perfectly flat response from your AU 70 just by flipping a switch BLEND CIRCUIT PERMIT CONTINUOUS SHIFT FROM MONAURAL TO STEREO As you turn the BLEND switch clockwise your AU 70 gradually shifts from monaural to stereophonic reproduction This feature enables vou to get full stereophonic effect by compensa ting program sources which give a particularly strong effect of the concert hall EASY TO READ THREE RANGE OUTPUT LEVEL METERS Each output level meter can be switched over to any of the three scales of 5 10 and 25 watts The meters not only give direct readings of both channels but also indicate any lack of balance between the right and left outputs These prove very useful in balancing the outputs THREE DIMENSIONAL PERFORMANCE POSSIBLE WITH CENTER CHANNEL OUTPUT TERMINAL Your AU 70 has an output terminal for the center channel amplifier Connect it to your monaural amplifier to produce a th
17. eS Fe See OPERATING INSTRUCTIONS amp SERVICE MANUAL 1 SIX STEREO CONTROL AMPLIFIER SANSUI AU 70 SANSUI ELECTRIC COMPANY LIMITED This amplifier has a maximum output of 50 watts 25W 25W and features an amazingly low distortion factor of not more than 0 15 at 20W A high quality amplifier with many exci ting features it is delivered to you with Sansui s fullest confidence This booklet explains the steps necessary for operating and caring for your new the AU 70 Read all the instructions carefully and retain for future use CONTENTS E ERIS ERI SPEGIBIGATIONS CHARACTERISTICS she cioe ncs MR 6 CONNECTIONS 19 9 10 SWITCHES AND CONTROLS RR MEC 11 12 OPERATIONS 5 7 12851514 HINTS ON DONE TENE 15 16 SERVICE NOTE Axis C MM 2 17 18 PARTS LIST eR ME 19 20 21 SCHEMATIC DIAGRAM 22 PARTS LAYOUT PP re 28 SANSUI STEREO CONTROL AMPLIFIER AU 70 FEATURES 7189A P P PRODUCES 40W WITHOUT DISTORTION MAX 0 95 AT 30 CPS AND 0 15 1 000 CPS The 7189A power tubes operate in class AB P P fixed bias for high fidelity reproduction Their combined maximum output is limited to 50 W The amplifier incorporates a multiplex feedback circuit tot
18. ed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Part No 15K 15K 0 100K 2 100K 2 50K 2 50K 80K 80K 1 5K 1 5K 2 0 2 0 150K 150K 20K 2M 2MQ 2 0 2MQ IMO IMO SOKO 50KO 50KO 50K 50K 50K 0 3000 3000 1 5K 1 5KQ 2KO 600K 600K 150K 150K 12K Q 12K 2 6K 2 6K 30K 30K 50K 0 30K 1 30KO 14 Enclosed Enclosed Enclosed Enclosed Watt 14 Watt 14 Watt Watt ls Watt Watt 14 Watt 14 Watt Enclosed in Enclosed in Enclosed in Enclosed in Enclosed in Enclosed in 1 14 Watt lo Watt Watt by Watt 15 Watt l4 Watt Watt 14 Watt Watt lL Watt Ly Watt 1 Watt Nomenclature in CRSO2 in CRSO2 in CRSO2 in CRSO2 10 10 10 10 10
19. ed on but A the unit does not work at all 1 Defective tube Check V V and silicon diodes 2 Abnormal voltage in tubes and other parts Check voltage in tube and other parts and replace if necessary If voltage is OK check AUX input circuit and hereafter B and TAPE does not 1 Defective head amplifier transistor section Replace transistor head amplifier unit unction 2 Defective selector switch Replace or repair S a and or Soe Sor 3 Loose contact or short circuit between input Replace or repair terminal and pin jack 4 Defective record player tape recorder or Replace others connected to the unit 5 Defective coupling condenser Replace C and or Cs Weak sound on AUX 1 Abnormal voltage in power circuit Check and repair PHONO and TAPE other parts A Normal voltage at every part 1 Defective fixed resistance but weak sound on AUX Check Reg R and Compound part CRSO1 5 2 2 Short circuit in output transformer Check T and Ts 6 Discharged capacitor Check Coo Cae tubular electro lytic capacitor Cog Aged tube Check Defective slide switch or selector switch Replace or repair Sap Sga Sec Normal voltage at every part 1 Defective selector switch Re
20. en the right and left speakers In this case you can count on the output level meters for a rough determination of the balance Also make sure that the BLEND knob is kept at the point where it cannot be turned clockwise any further When you supply power to the player from the power plug receptacle on the back of your amplifier do not forget that the player is switch ed off when you switch off the amplifier BROADCASTS In the case of A and B above 1 Set the SELECTOR switch at TUNER 2 Set the MODE switch at STEREO or STEREO REV in the case of A and at R or L according to the channel selected in the case of 3 Tune in with the tuner 4 Use other adjusting knobs and switches to get the most satisfactory performance In the case of C 1 Set the SELECTOR switch at AUX 2 Set the MODE switch at STEREO or STEREO REV 3 Tune in with the tuner Prepare the FM MPX adaptor for stereophonic reception 5 Use other adjusting knobs and switches to get the most satisfactory performance When you use a tuner or FM MPX receiver read the instructions for them carefully There should be no mistakes in connections and operation When you use our TU 70 follow the instructions for A When you use an FM tuner without Multiplex and MP 2 follow the instructions for C USE A MICROPHONE You can use microphones with your AU 70 amplifier high imped
21. er output terminal LINE to R and L R or L in the case of monaural operation of the TAPE MON terminals the back of your amplifier 2300000000000000000000 909000090000000000000900000002900 00000 0000000000000 Tape deck Tape recorder recorder DIN 10 SWITCHES AND CONTROLS POWER INDICATOR This lights up when power is being sup plied It remains on while the amplifier IS in operation HEADPHONE JACK When you want to avoid disturbing others or when you use the amplifier as a monitor connect headphones to this jack You can still enjoy stereophonic reproduction through the headphones For this pur pose you can use any type of headphones or earphones if its plug fits into the jack But use dynamic headphones designed for stereophonic reproduction if possible SPEAKER SPEAKER OFF When you use headphones with the head phone jack set this switch to OFF to cut off sound to the speakers This feature enables you to enjoy stereophonic repro duction without disturbing others 4 PRESENCE If the Tone Control alone is used for bass compensation slightly higher frequencies are compensated at the same time To avoid this turn this switch ON This sets the turnover at 150 cps changing speaker damping and frequency response characteristics to compensate bass As a result all sounds beco
22. er for operation to use the upper R terminal for connection Be sure to set the MODE switch to the connected channel HUM AND HOWLING When you play a record or tape you may some times hear unpleasant humming or howling This does not mean that your amplifier is defective In most cases humming or howling is a result of these causes you place a record player on or near the speaker box the vibrations of the speaker cabinet caused by the sound waves from the speaker are transmitted to the player and cause howling To prevent this keep the record player away from the speaker cabinet or put a thick cushion be tween the player and the cabinet A low buzzing sound will also be produced if you do not use shielded wires for connection If this is not the cause examine the connections closely Make sure that the earth and live ends are not reversed so that the motor and arm inade quately grounded W CONNECT LEADWIRES PRO PERLY Connect leadwires properly to the speaker and other input and output terminals If connections are loose or touch other parts your amplifier will not work properly Moreover it may produce noise If you use your amplifier in such a way for a long time it may eventually break down Finally read the instructions for your tuner or tape recorder carefully before you connect it to your amplifier LEVEL METER SWITCH This is used to select the most suitable meter sens
23. erminals on the back of your amplifier When your amplifier will not work normally and may vou use two microphones connect one to R and also go out of order the other to L 9009090c090 50 0690 50c00 0 0690 0C00 0 0030 0 0020 002070080020 0020 00202009000089 99060 5020c09400020 0090 0 0 009020 O 99090900000090000009009000000000000990000000000000000006000000000000000000000 1 1 i al ___ 5600909 ____ CARTRIDGE SWITCH Set this to MAG X TAL depend ing on your player cartridge magnetic or crystal Player magnetic Player crystal Microphone CONNECTIONS TUNER You can listen to broadcasts easily by connecting vour amplifier to a tuner and MPX adaptor A STEREO TUNER Connect tuner output to the R and L TUNER terminals on the back of vour amplifier B MONAURAL TUNER Connect tuner output to either R or L of the TUNER terminals on the back of vour amplifier C FM MONAURAL TUNER AND FM MPX ADAPTOR Connect
24. ined sound A B R Mono R Signals fed into A come out of A s and B s speakers Use this posi tion for reproducing mono broadcasts and tapes L Mono L Signals fed into B come out of and B s speakers This position is rarely used OPERATIONS RECORD PLAYING I a to Set the SELECTOR switch at PHONO Set the MODE switch at STEREO or STEREO REV at R L in case of mon aural operation Switch on the player put on a record and adjust the number of revolutions as necessary before placing the pickup on the record Balance the sounds from both speakers by means of the BALANCE knob while watching the output level meters Adjust the amount of sound by means of the VOLUME knob Other adjusting knobs and switches can be used to get the most satis factory repreduction When you play a monaural record on a stereo record player follow the same procedure as for stereo records This will give you better results Catridges are either magnetic or crystal Both can be used with the AU 70 but if possible use a magnetic type for the highest fidelity If you feel that right and left are reversed when playing a stereo record turn the MODE switch to STEREO REV balance the sounds from both speakers play a monaural record in the same way as a stereo record and adjust the BALANCE switch in such a way that you feel that the sound comes from a point midway betwe
25. itivity from the three ranges of 5 10 and 25 watts The variable sensitivity is intended to make it easier to watch needle movement high up to 5 watts medium up to 10 watts low up to 25 watts maximum output Choose the appropriate range according to volume level vou want AC OUTLET The AC outlets on the back panel are connected or disconnected by the power switch on the front panel The total capacity is 80VA 30VA and another 50VA Be sure to use them within the limit WHERE TO BE PLACED The amplifier should be installed to the place as given below Easy to ground 2 Floor not vibrated Fig 3 SOLDERING THE LEAD TO THE PIN PLUG SHIELD WIR PIN PLUC 2 SOLDER SHELL CUT OFF EXCESS WIRE ED mS ST jo 1 aM VT SOLDER TIP gt VEA C 0 MP L 1 n 3 Not wet and dusty 4 Not exposed to the sun 5 Well ventilated 16 SERVICE NOTE Symptom Probable Cause What to Do No power when power switch is 1 Defective power switch Replace pushed on 2 Defective line cord Replace 3 Loose contact between plug and socket or Recondition or replace defective plug 4 Blown fuse Replace If again blown after replacing check power transformer T amp path condenser in power circuit for short circuit Power indicator is lit when power switch is push
26. l ys d 1 IRs 003 RN s ana E UNE ELS DEL OREL UND ees Ss b By OFF 2 ON LOUDNESS Sg lad OFF ES 2 ON TONE DEFEAT 58 5 OFF T og 2 ON LOW FILTER x 6 OFF Syta 8 2 UN HIGH FILTER LEVEL ow 2 LEVEL mes 3 LEVEL PRESE 5 Sua LEVEL METER 2 QN PRESERCE 1 OF 12 34 OFF TT i Sip a b 2 OW AC 5 ON Pa 2 OFF SPEAKER a BW ban ou 12 34 OFF Sua LEVEL METER aui n lm 5 1 2 3 5 OFF Sim 071 4 on 4 12 35 OFF E Pad qr Fac 4 ON Gg 2 CU CU F s ci gt inc Tw HEAD PARTS LAYOUT 2 v 2 7 2 7 gt GANG GANS 7189 CS ita TUNER 6 PHONO MIC TAPE HEAD REC TAPE MON AUX YELLOW fo on EARTH TUNER ix diaa y 0284 i MIC GRSK i 2 8 6 S3 E amp 6 AUX 6 lt N Ej LEVE Sus XT l P OIL P o MP 85 5T 5 x x S Gun wo HEAD MP 1 50005 26 2 5 ANS PHONE MYLAR 2 ON LOUDNESS
27. me impressive and you can enjoy clear magnificent bass 5 POWER This switch is used for connecting and disconnecting the power supply Push the button for power Push it again to shut it off The switch also activates and de activates the power supply plug receptacles on the back of the amplifier owe OUTPUT LEVEL METERS The right and left meters indicate the out put levels of the right and left speakers respectively Since output is shown separately for each channel the meters provide easy balance adjustment Besides you can watch changes in the output of each channel during ope ration Each meter can be set to any of the three ranges of 5 10 and 25 watts by means of the output level meter switch on the back of the amplifier Choose the appropriate range according to the output you want When the MODE switch is set to R L the meter for L or R does not work 7 LOUDNESS When sound volume is at a low level you feel as if bass and treble are missing In such a case turn this switch ON to compensate bass and treble This will make vou feel as if you were present at an actual concert LOW FILTER for eliminating low frequency noise Turn this switch ON to reduce phono motor and other unpleasant low frequency noises 9 HIGH FILTER for eliminat ing high frequency noise Turn this switch ON to reduce relatively high frequency noise such as the scratch
28. onal effect Speakers suitable tor the AU 70 are 20 to 30 cm coaxial speakers and for the best musical repro duction two or three way speaker systems which use different speakers for different frequency RECORD PLAYER Bre e 1 Connect the output terminals to the PHONO In choosing the cabinet take account of tonal R and PHONO L terminals in the case quality in addition to design of monaural reproduction to either of these CAUTION terminals on the back of your amplifier with shielded wires If you find that the sounds from both speakers do not mix well but leave a sort of vacuum in 2 3 gh are ampliher to MAG X TAL according midway between the speakers you can conclude puse eb Vic to the type of your cartridge that the amplifier and the speakers do not match 5 roy e WT lai Paty 3 Connect the power cord plug of the player ry le Fr We Gp in polarity phase TEYSIUE NUS to the power plug receptacle on the back of and connections of either speaker vour amplifier When you use two pairs of speakers for stereo phonic reproduction make sure that the speaker MICROPHONE output terminal connections do not cause contact between R and L and that the terminals connected properly If the connections are faulty 2 Set the cartridge switch on the back of your Connect the microphone to or L of the MIC t
29. place or repair Soa Sep See Sor Sga and but weak sound on PHONO Sub and TAPE 2 Abnormal input circuit loose contact Replace or repair between input terminal and pin jack defective shielded wire 3 Defective record player tape recorder or Replace others connected to the unit Defective coupling condenser Check C Cz Cs Cg and Ca gt 5 Discharged bypass condenser Check Cz Co and Cio _ _ Symptom Probable Cause What to Do 1 Aged tube Check V Vs4 Check and repair and A Distorted sound on AUX 2 Short circuit in output transformer 3 Defective loudspeaker Replace 4 Defective record player adaptor or others Replace connected to the unit ae SSS P B Distorted sound on PHONO 1 Defective record player tape recorder or Replace and TAPE others connected to the unit 2 Defective tubular electrolytic capacitor Replace C and or 3 Disconnection at fixed resistance Chech Re Ris Ris Eg Ris Rio Reo Re and Ros A Hum on AUX 1 Electrolytic capacitor discharged Check C4 2 Defective tube Check 3 Defective record player adaptor or others Replace connected to the unit 4 Hum b
30. r Resistor Resistor Resistor Resistor Resistor tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular tubular 0 01 xF 0 003 uF 0 003 uF 0 1 uF 0 1 uF 4uF 4 0 001 0 001 150pF 150pF 0 003 F 0 003 F 0 03 pF 0 03 F 201 0 1 uF 0 1 uF ApnF 0 005 0 005 0 005 0 005 0 01 xF 0 01 uF 300pF 300pF 200pF 200pF 200pF 200pF 30 xF 2 0 2 0 5 0 5 HF 80pF 20 4 F 20 4F 20 uF 20 I Omenciarur a 5 400WV 400WV 250WV 250WV 20 20 400W V 400WV 10 10 10 10 10 10 MP MP Electrolytic Electrolytic oil Enclosed Enclosed Enclosed Enclosed Enclosed Enclosed 300WV 250WV 250WV 6WV WV 20 20WV 400WV 400WV 400WV 400WV 400WV 400WV Enclosed Enclosed Enclosed Enclosed Enclosed Enclosed 10 5 2 CRSO2 5 2 5 2 CRSO2 5 2 Electrolytic MP MP Electrolytic Electrolytic Electrolytic Electrolytic 10 10 5 1 CRSOI 5 CRSOI CRSOI CRSOI oil oil oil oil oil oil 6WV WV 250WV 250WV 250WV 250WV 500WV 5 250WV 250WV 250WV 250WV 300WV 300WV 300w V 10 10 10 10 10 10 10 10 10 10
31. ree dimensional effect EQUIPPED WITH ADVANCED HIGH PERFORMANCE ACCESSORY CIRCUITS Your AU 70 is equipped with various advanced accessory circuits such as loudness control low and high filters tape monitor tone defeat pre sence blend speaker switch and headphone jack SPECIFICATIONS CHARACTERISTICS VACUUM TUBES TRANSISTORS AND DIODES TONE CONTROL CHARACTERITICS FREQUENCY RESPONSE CHARACTERISTICS MAIN AMPLIFIER MAXIMUM OUTPUT 25W 25W 50W total 7189A 4 2 12 7 x3 OA 91 germanium HARMONIC DISTORTION diode 2 258 381 transistor x 4 SD IB silicon diode 019 ae Rester comms TTT TTN eer n TC Se a 2 SW 0503 silicon diode x 1 TOTAL 9 tubes and 9 diodes Max 0 15 at 20W for 1 000 Hz Max 0 95 at 20W for 30 Hz RESPONSE dB INTERMODULATION Cot 110 224 EN POT TET EX co DISTORTION Max 0 852 at 20W 50 Hz POWER SUPPLY 117V AC 50 and 60 Hz E POWER CONSUMPTION 150 ERE FREQUENCY RESPONSE 10 80 000 Hz at 1 Ps AE uL LL 115 10 OUTPUT IMPEDANCE 8 and 16 ohms DIMENSIONS Width 151 Depth 12 9
32. speakers FUSE The amplifer does not work when the fuse 15 blown In such a case disconnect the power cord and replace the fuse on the back of the amplifier Use a 3 ampere fuse encased in a glass tube Never risk the danger of using fine wire or a fuse of a larger capacity as a substitute the fuse has burnt out because the amplifier is out of order locate the trouble and repair it before replacing the fuse The fuse blows if you use an AC plug receptacle larger than the specified capacity 80 VA for two HEAT GENERATED BY AMPLI FIER The top of the amplifier case becomes considerably hot after many hours of continuous operation But this should not worry you because air vents are provided on the top and back of the case If you place something on the amplifier or put it in a closed box or keep its front panel facing Fig 1 uw e up it might go out of order CONNECTIONS When you connect your amplifier to a tape recorder or tuner be sure to use an adequately thick shielded wires If you use untwisted vinyl cord like those used for lights you will suffer from hum Furthermore do not use a wire longer than 2 meters about 6 5 ft because the longer the connecting wire is the greater the attenuation of treble becomes For connection to a tuner or FM adaptor use a wire 1 to 1 5 meters about 3 3 to 4 8 ft long When you use the amplifier for monaural reproduction it is easi
33. tor for a three head tape recorder follow the same procedure as the one for playing tapes on a recorder When you use a recorder read the instruction manual carefully to avoid errors in connection and oper ation Unless you use your amplifier as a tape monitor or for playing a tape with a tape recorder be sure to switch off the TAPE MONITOR switch Connecting a tape recorder can be done by using either a single connection connector or by pin jacks The single connection plug conforms with German DIN standard specifications It makes it easier to connect the tape recorder to your amplifier because it has a five pin plug for both record and playback When you use your amplifier as a tape monitor turn on the TAPE MONITOR switch if you want to hear the sound you are recording HINTS ON USE SPEAKER POLALITY If the phase polarity viz and of the right and left speakers is not correct sounds at the center of the frequency range become weak You will particularly sense an attenuation of bass To make sure that speaker polarity is all right play a monaural record on a stereo record player If the polarity is reversed you will have the result mentioned above In such a case reverse the polarity of either speaker Connect the lead wire to When both speakers are thus made to agree in polarity you will feel as if the sound comes out of a single speaker placed midway between the right and left
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