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Hafler DH-500 Stereo Amplifier User Manual

1. The wiring of the amplifier is now to be completed with the installation of the power transformer and two disc capacitors The following instructions refer to the 120 volt transformer supplied for the USA If your kit is supplied with the optional multivoltage transformer for overseas use separate instructions in this manual will diagram both in pictorial form and schematically the connection for each line voltage NOTE FOR MULTIVOLTAGE option The following steps which describe the installation of the capacitors and the connec tion of the two red leads and the red yellow lead of the transformer are to be followed for all units Only the con nections for the black and black white transformer leads and the additional leads supplied on your transformer may differ You should follow all the other steps to the comple tion of your amplifier 01 Select the 4 sets of 10 hardware and the 4 washers and the power transformer Carefully place the transformer in position making sure no wires are trapped with the transformer leads protruding to ward the large capacitors You may if you choose shorten any lead for neatness but be sure you do not cut any lead too short as leads which are cut too short for re use may void the transformer war ranty If you are using the multivoltage transformer be sure you leave leads long enough for possible alternative voltage applications The washers are to be placed on the screws on top of the
2. Connect one end to RY lug 4 S Connect the other end to red output termi nal LR S 63 Prepare another 3 white wire Connect one end to RY lug 6 S Connect the other end to output terminal RR S 64 L Prepare a 16 green wire Connect one end to black output terminal LB S Connect the other end close to the center of the bare wire between the two capacitors S 65 LL Prepare an 18 green wire Connect one end to out put terminal RB S Connect the other end to the bare wire between the two capacitors S 66 L Prepare an 11 E green wire Connect one end to dual fuse clip FL lug 4 S Connect the other end to CR lug 4 67 L Prepare a 7 white wire Connect one end to FL lug 3 S Connect the other end to CL lug ml 68 _ Prepare a 12 white wire Connect one end to FR lug 7 S Place this against the chassis and connect it to CL lug l 69 Prepare a 13 white wire Connect one end to CL lug 1 S 3 Connect the other end to the rectfier block DB lug 2 S This is the lug marked on the rectifier 70 L Prepare a 71 2 green wire Connect one end to FR lug 8 S Connect the other end to CR lug 4 71 J Prepare another 8 green wire Connect one end to CR lug 4 S 3 Connect the other end to DB lug 3 S 72 L Strip a 3 4 piece of light wire bare Connect it be tween the short ground lug of input socket LS and the separate ground lug between t
3. 15 R402 C401 J403 INPUT 3 o 9401 OUTPUT p o o e e LEFT CHANNEL Do gt RY 90V Ce 4 6 H e e C106 e o 0 o PC Rios e o RIO AUDIO FROM AMP RU ri02 RIOS Rios clo Cw2 coa TB402 TB40l TR4OI SCHEMATIC DIAGRAM l20V O Copyright 1985 16 All rights reserved COMPONENT VALUES All resistors are a watt 5 carbon film unless otherwise noted part No All capacitors are 100 volt minimum unless otherwise noted Part No RI 470 000 ohms RC044 Cl 2 mfd 50V Film CP115 R2 1 800 ohms RC023 ee 330 pF Film CP 134 R3 47 000 ohms RC043 c3 Ol mfd Film CC124 R4 47 000 ohms RC043 c4 001 mfd Film CP136 R5 560 ohms RC045 C5 OO1 mfd Film CP136 R6 560 ohms RC045 C6 1 mfd Film CC125 R7 47 000 ohms RC043 c7 I mfd Film CC125 R8 560 ohms RC045 C8 470 mfd 6 3V non polar Electrolytic CNI13 R9 560 ohms RC045 c9 150 pF Film CP133 R10 1 800 ohms RC023 C10 330 pF Film CP134 R11 1 800 ohms RC023 Cl 1 01 mfd Film CC124 R12 270 ohms RC029 C12 100 mfd 100V Electrolytic CL122 R13 47 ohms RC039 C13 01 mfd Film CC124 R14 47 ohms RC039 C14 100 mfd 100V Electrolytic CL122 R15 47 ohms RC039 C15 Ol mfd Film CC124 R16 47 ohms RC039 C16 01 mfd Film CC124 R17 1 800 ohms RC023 C17 150 pF Film CP133 R18 1 800 ohms RC023 C18 Ol mfd Film CC124 R19 270 ohms RC029 C19 01 mfd Film CC124 R20 1 800 ohms RC023 C20 1 mfd Film CC125 R21 82 ohms RC053 c2l mfd Film CC1
4. 2 amp fuses and install them in the round fuse holdders on the back of the chassis This will keep the caps from being loosened and lost This completes the basic mechanical assembly of the chassis Set it aside for the present 20 L Select the large front plate the smaller front panel with the edges turned back the two handles and four flO screws With the power switch cutouts aligned place the screws through the panel from the rear through the front plate and secure the handles Set this assembly aside 21 L Select the amplifier module Handle it with care The fan is mounted on the front of the module with a foam gasket on the rear On the bottom two thermal sensors for the fan and two safety thermal breakers are already mounted on the heat sinks With the module upside down and the fan away from you to keep the left channel on the left for consistency cut the right fan lead to 5 3 4 strip it 1 4 and connect it to TS2 lug 6 22 _ Cut the left fan lead to 4 strip it 1 4 and connect it to TBI lug 1 A soldering iron will be used regularly from now on Be sure you wipe its tip frequently with a damp cloth or sponge as a bright tip will make connections easier with less likelihood of overheating components If it is difficult to heat a connection in a couple of seconds apply a small amount of fresh solder to the tip so it can flow around the connection and provide good heat transfer There are
5. 200 240 volt AC lines See page 18 A 220 volt fan must be used part AAI28 and will have been fitted if specified 82 _ Select the remaining 300 ohm resistor Trim each lead to 3 4 and place this resistor on the back side of the terminal strip and connect one lead to LT lug 5 S 3 Connect the other lead to LT lug 7 S 2 83 Select the white wire from the left circuit board protruding from underneath the module Connect it to RY lug 7 S 2 84 _ Select the long white wire from eyelet 5 on the right circuit board Place it under the relay and connect it to RY lug 9 S 2 85 Connect the short white wire from the left side of the module to fuse clip FL lug fl S 86 L Connect the longer green wire from eyelet 7 on the left side to the bare wire between the 2 large capacitors S Place it down against the chassis 87 Connect the green wire from eyelet 10 on the left side to FL lug 2 S 88 L Connect the short green wire from eyelet 10 on the right side to FR lug 6 S 2 89 LJ Connect the long green wire from eyelet 7 on the right board to the bare wire between CL and CR S Place this wire down against the chassis One more connection will be made at the center of this bare wire 90 _ Connect the white wire from eyelet 3 on the same board to FR lug 5 S 2 Now is the best time to turn the amplifier upside down and shake out any loose bits of solder wire clippings etc
6. 5 carbon film RC 4 470 R5 47 ohms l 4w 5 carbon film RC 4 470 R6 8 2K 1 4w 5 carbon film RC 2 822 R7 8 2K 1 4w 5 carbon film RC 2 822 R 47 ohms 1 4w 5 carbon film RC 4 770 RO 47 ohms 1 4w 5 carbon film RC 4 770 RIO 2 2K 1 4w 5 carbon film RC 4 222 RII 2 2K 1 4w 5 carbon film RC 4 222 R12 22 1K 1 metal film RMP 4 2212 R13 I00 ohms 1 4w 5 carbon film RC 4 101 R14 100 ohms 1 4w 5 carbon film RC 4 101 R15 47 ohms 1 4w 5 carbon film RC 4 770 R16 3 8K lw 5 metal film RM 1 332 R17 3 3K Iw 5 metal film RMI 332 Cl 1 OmF 16V non polarized CERNP 106 c2 6 8pF 100V dipped mica CM 068 c3 22mF 25V electrolyte CER 226AA c4 _ 22mF 25V electrolyte CER 226AA QI BC5S50C NPN nansistor SSH 650 Q2 BCSS5OC NPN transistor SSH 650 03 BC560C PNP transistor SSH 65 1 Q4 BC360C PNP transistor SSH 65 1 Q5 MPSA63 PNP transistor SSH 695 Q6 _ MPSAI13 NPN transistor SSH 645 INSTRUCTIONS FOR THE HAFLER DH 502 AMPLIFER BRIDGING KIT FOR THE DH 500 The DH 502 Amplifier Bridging Kit for the DH 500 consists of a PC 7A circuit board comprising a 6 transistor phase inverting amplifler a mounting bracket necessary hardwareandconnecting wire Installation may take about an hour All changes to the amplifier wiring are performed on the right channel the side nearest the power switch Only the left channel input will be utilized after conversion so an additional pair of input wires will be connected to that jack to ena
7. end of the red wire to eyelet 1 of the board which is to your left as you face the rear of the module Eyelet 1 is the upper eyelet Con nect the black wire to eyelet 2 Be sure both eyelets are securely soldered Place these wires down under the module 32 Prepare an 8 1 2 black wire and a 7 1 2 yellow wire Allow the black wire to project 1 2 beyond the yel low wire and twist these together The black wire connects to the upper eyelet 2 of the circuit board to your right S Connect the yellow wire to eyelet 1 S Place this pair under the module Now turn the module around so the fan is toward you The eyelets are numbered consecutively one to each cir cuit tab visible along the edge of the board from 3 to 10 The small tab numbers are visible adjacent to each tab on the underside of the board 33 Prepare two 7 white wires Connect one to the right circuit board eyelet 8 towards the bottom S Connect the other wire to eyelet 6 S You may find it easier to work if the module is laid flat on its back foam gasket Bend these wires toward the bottom of the fan bracket and twist them to gether throughout their length 34 Prepare a 13 green wire Connect it to eyelet 7 of the right board S 35 Prepare an ll white wire Connect it to eyelet 5 of the right board S Bend this wire toward the bot tom of the bracket 36 _ Prepare a 3 green wire and connect it to eyelet 10
8. of the right board S 37 U Prepare a 612 white wire and connect it to eyelet 3 of the right board S as U Prepare a 13 green wire and connect it to eyelet 7 of the left board S 39 U Prepare a 13 white wire and connect it to eyelet 5 of the left board Bend this wire toward the bottom 40 Prepare two 9 white wires Connect one to eyelet 8 of the left board S Connect the other to eyelet 6 S Bend these toward the bottom and twist them together 41 Prepare a 3 white wire and connect it to eyelet 3 S 42 O Prepare a 6 green wire and connect it to eyelet 10 S Set the module aside temporarily CHASSIS WIRING 43 _ Select the chassis and the 39 mfd capacitor Trim each lead to 1 2 Connect one lead of the capacitor to LT lug 3 Connect the other lead to lug 4 44 Select the silicon diode Note that one end has a stripe for 1dentification Connect the striped end to LT lug 3 Connect the other lead to lug 2 45 L Select the 12 watt megohm brown black green resistor Trim each lead to 1 2 and connect one lead to LT lug 2 S 2 Connect the other lead to LT lug Hl 46 L Prepare a 71 2 white wire Connect one end to LT lug 1 S 2 Connect the other end to fuse clip FC lug ffl S 47 Prepare a 12 green wire Connect one end to LT lug 3 S 3 48 _ Select one of the spade lugs Connect it to the other end of the green wire just attac
9. relay to cut off the output briefly because the sensing circuit sees this as DC offset If this 1s annoy ing and you are willing to accept a little less relay protec tion you you can change R107 and R108 to a higher value These are now each 39000hms orange white red and are located above the IC on the small circuit board PC 9A We suggest 4700 ohms as the next step At the other extreme it is possible to increase the sensitivity so that the relay would protect the speaker if a stylus were dropped on the record but then it might be activated by powerful low fre quency transients If the fan does not turn or makes a ticking noise make sure it is properly centered in its supports and that ship ping abuse has not twisted it so the blades are rubbing the housing Moderate pressure on the struts will recenter it CIRCUIT DESCRIPTION The DH 500 amplifier components have been selected to pro tect against failure and all parts are operated conservatively to assure unaltered performance and proper operation for many years The semiconductors have been thoroughly researched and selected for minimum noise and distortion in sustained use and the printed circuit board associated with the audio signals has been pretested in the circuit to insure that each kit amplifier will meet or exceed all specifications The amplifier stages are fully DC coupled with a dual differ ential pair for the input and a fully complementary MOSFET output
10. secure the cover along the top front sides and rear Set cover aside DO NOT GRAB THE AMPLIl FIER PANEL OR HANDLES WHEN THE COVER IS RE MOVED You might bend the chassis Turn the amplifier over or stand it on the nansformer end Loosen but do not remove the two front screws which secure the amplifier module near the front center of the chassis Remove the two screws at the rear which secure the module Return the amplifier to its upright position Prepare one each red and green wires each 16 long Twist them together throughout their length Select the PC 7A circuit board Note that the eyelets arcnumbered on the circuit side of the board with eyelet 1 to the left when the row of eyelets is nearest you and the board is upside down to make soldering easier Connect the wires from the components side of he board and be sure each is securely soldered to the circuitry Connect the red wire of the twisted pair to eyelet 1 of PC 7A S Connect the green wire to eyelet 3 S Prepare a 3 1 2 green wire and a 4 red wire With one pair of ends even twist these together At the uneven ends connect the green wire to cyelet 4 of PC 7A S Place the pair off toward eyelet 1 and connect the red wire to eyelet 6 S Prepare a 5 red wire and a 6 green wire Twist these together with one pair of ends even At the even ends connect the red wire to eyelet 2 S Connect the green wire to eyelet 5 S Unsolder the
11. solder and wire clippings from the chassis Three wire ties have been included in the kit which you may wish to install around groups of wires to make your finished amplifier look neat Because it is desirable that the ground wires which connect between CL and CR be kept close together we suggest using one tie at the base of the capacitors 100 _ Select the front panel assembly and the power switch and make sure that the power switch is oriented with the red window 3 lug or separate lug to the right or nearest edge The switch is a press snap fit from the outside of the panel 101 L Select 4 sheet metal screws and bring the front panel to its approximate position Carefully attach the 3 wires to the switch lugs white to the left green to the right Push the lugs fully on and as semble the front panel to the chassis NEVER AT TEMPT TO PICK UP THE AMPLIFIER BY THE HANDLES IF THE COVER IS NOT SCREWED IN PLACE 14 102 Select the remaining sheet metal screws and the cover Before closing up the unit plug it in and check to see that the fan turns Because it normally operates at low voltage for low speed a new fan may need a bit of encouragement at first Any stiff ness is normally overcome after a few minutes op eration Once you are sure it turns on each time the power switch is turned on secure the cover 103 LJ Peel off the backing from the serial number label and affix it to the bottom of the chassis CONGR
12. systems Smaller fuses tend to blow too easily and it is unlikely you will be using speakers with low power ratings with the DH 500 Larger fuse sizes may not adeguately protect the majority of speakers intended for home listening If the manufacturer of your speakers recommends a specific fuse value for their protection you should obtain 3AG type fuses of that value and substitute them for the ones supplied The speaker fuses are included in the amplifier design solely for speaker protection They do not protect or affect the amplifier s operation A blown speaker fuse does not indicate malfunction simply a higher than normal output signal If the amplifier produces a low level distorted signal a blown speaker fuse is the most likely cause We do not recommend the use of a slo blo type fuse for speaker protection If your speakers can handle the higher power levels safely and you wish to install fuses of higher ratings we suggest for the sake of the speakers that you increase fuse size in 1 2 ampere increments THIS AMPLIFIER IS ABLE TO DELIVER SUBSTAN TIALLY MORE POWER THAN MOST SPEAKERS CAN SAFELY TOLERATE Therefore the Hafler Com pany cannot assume any responsibility for damage to the load loudspeaker because the choice of fuse six is in your hands The 2 amp fuse with an 8 ohm load permits continuous power up to 32 watts with peaks well above that 2 1 2 amps passes 50 watts 3 amps 72 watts 5 amps 200 watts We
13. unchanged If the amplifier is to be operated with line voltages between 200 and 240 volts a different fan part FAA128 is required the 600 ohm resistors must replace the 300 ohm values and the 7 ampere slo blo fuse must replace the 15 ampere line fuse 100 V 120V IJ BKR BR R KIT PARTS LlST Minor variations may sometimes be encountered in value or appear ance These will not affect performance Some of the hardware listed here has been used to secure parts for shipping the kit o tb ra Y ee Chassis Cover Front plate rack mount Front panel inside Handle Amplifier module with fan AA1 13 Power transformer AC line cord with plug 16 Ga Bracket capacitor round Capacitor 20 000 mfd 100 volt Circuit board PC 9C assembled Label serial number Relay enclosed Manual Warranty card Wire white 18 Wire green 18 Wire Yellow 18 Wire Black 22 Wire Red 22 HARDWARE ENVELOPE Lug ground internal tooth 6 Lug plain connecting 10 Nut 4 40 KEP Nut 6 32 KEP Nut 10 32 KEP Nut 1 2 Screw machine 4 40 x 5 16 Screw machine 6 32 x 1 2 Screw machine 10 32 x M Screw SEMS 10 32 x 1 4 Screw sheet metal 6 x 38 Screw machine 6 32 x 3 4 Washer flat 10 x 7 8 Washer internal tooth 1 2 Washer rubber M Wire ties nylon 4 Part No MS127 MS126 MS161 MS128 HZ167 AH324 TA116 WA016 HZ124 CL123 AC009 LR015 sz1
14. wire is inserted from the outside This requires an iron with a small tip preferably chisel shaped and some care on your part It is easiest to melt a small blob of solder on the tip and position it at the eyelet so that the solder blob more than the tip itself is heating the eyelet If the eyelet is first filled with solder and the wire end is pushed all the way through the heated eyelet first then withdrawn part way to expose a bit of the bare end outside the board before the solder cools you should have a firmly soldered connection if it cools undisturbed Always tin a wire that is to connect to an eyelet After soldering go back and check by twisting each wire to make sure nothing moves on the other side of the board It is wise to check any existing wire connected to an adjacent eyelet to make sure your work has not loosened it When connecting heavy gauge wire to the eyelets if you get too much solder on in the tinning process it will be hard for the wire to penetrate the eyelet 10 While excessive heat or careless scrubbing with the iron can lift the circuit foil from the board more people tend to use insufficient heat making it difficult for the solder to flow smoothly around the connection A smooth bright connection is important 31 Prepare an 8 black wire and an 8 red wire Start with the red wire 1 2 longer at one end and twist these wires together throughout their length Con nect the longer
15. 13 Swcnedli2zcOh Part No HZ115 HZ1 16 HKIII HK112 HK113 HK118 HA1 13 HA116 HA119 HA118 HP 17 HA1 15 HW114 HW116 HR117 HR138 SMALL PARTS ENVELOPE Part No 2 Bracket L shape 2 MS153 Bracket L shape 3 MS154 Capacitor 0 005 mfd Disc CZ113 Capacitor 0 01 mfd Disc ez112 l Capacitor 0 39 mfd Film CE117 Diode IN4003 QDII5 l Inrush Limiter RZ016 l Resistor 1 megohm Mwatt RD113 2 Resistor 300 ohm 7 watt RWOI5 3 Spade lug terminal xzol4 LARGE PARTS ENVELOPE Diode block silicon rectifier QD117 4 Foot rubber HR146 Fuse clip single XA012 2 Fuse clip dual XA014 2 Fuse holder round panel mount XA013 2 Input socket XPO14 Power switch SLllU Strain relief plastic HR144 1 Terminal post black complete w black washer and 2 nuts XK013 2 Terminal post red complete w red washer and 2 nuts XK014 Terminal Strip 7 lug XK019 FUSE ENVELOPE 2 2 ampere SF011 2 5 ampere SF012 4 10 ampere SFO13 l 15 ampere slo blo SF014 For Alternate M ulti Voltage Transformer Only Power Tmnsformer TA117 Terminal strip 3 lug XK017 Screw machine 4 40 x 5 16 HA1 13 Nut 4 40 KEP HKIIl Fuse 7 ampere slo blo SF021 2 Resistor 600 ohm 7 watt RW024 For use with 200 240 volts AC a different fan part AA128 must be fitted to the amplifier module 8 0 DH 502 INSTALLATION INSTRUCTIONS Disconnect AC power from the DH 500 and remove all connect ing cables Remove the 17 screws which
16. 25 R22 560 ohms RC045 c22 mfd Film CC125 R23 470 ohms RC04 1 C23 OO1 mfd 250V Film CP136 R24 10 ohms RCO 3 C101 39 mfd Film CEl17 R25 33 000 ohms RC036 C102 39 mfd Film CEl17 R26 3 300 ohms lw metal film RZ013 C103 39 mfd Film CEI 17 R27 1 000 ohms Ya w metal film RM02 C104 1 mfd 25V Non polar Electrolytic CN114 R28 150 ohms 4 w metal film RMO13 C105 22 mfd 100Y Electrolytic CL125 R29 1 800 ohms RC023 C106 Ol mfd 1000V Disc CZ112 R30 82 ohms RC053 C401 680 pF Mica CM121 R31 47 ohms carbon comp RZOll C402 1 mfd Film CC125 R32 47 ohms carbon comp RZ011 C403 1 mfd Film CC125 R33 220 ohms Y w RDI 14 C404 20 000 mfd 100V Electrolytic CL123 R34 2 200 ohms 2 w RDI15 C405 20 000 mfd 100V Electrolytic CL123 R35 10 ohms RC013 C406 01 mfd 1000V Disc CZ112 R36 l ohm 10 w RWO12 C407 39 mfd Film CEl17 R37 lOohms 5 w RWO13 C408 005 mfd 1000V Disc CZ113 R38 28 000 ohms Ya w metal film RM053 D1 D8 1 N4 148 Diode QD116 R101 100 000 ohms RCO17 D9 FDH400 Diode QD121 R102 120 000 ohms RCO19 D10 FDH400 Diode QD121 R103 150 000 ohms RCO2 I Dll 1N4148 Diode QD116 R104 150 000 ohms RC02 1 D12 IN5240B10V Zener Diode ODIII R105 27 000 ohms 4 w RD122 D13 1N5240B10V Zener Diode QDIll R106 22 000 ohms RC026 D14 1N4148 Diode QD116 R107 3 900 ohms RC037 D15 1 N4003 Diode QDIIS R108 3 900 ohms RC037 D16 1 N4003 Diode QD115 R109 22 000 ohms RC026 D101 IN5240B10V Zener Diode ODIII RI 10 27 000 ohms Y w RD122 D102 IN5240B10V Ze
17. 4 R5 c2 R6 i R12 R15 4 6 UL INVERTED OUTPUT R7 TO DRIVER CARD RBS S R9 ro oe C4 R10 R14 R17 QE B LIMITED WARRANTY The parts in the DH 502 are warranteed for a full year from the purchasedateincluding parts and labor If a defective componcnr is found on a circuit board or in the kit simply return the individual part or if the problem is unknown retumthedefcctive board to the factory prepaid together with the serial number and a copy of the dated bill of sale and it wil be repaired or replaced at no charge This warranty is limited to repair or replacement of the DH 502 bridging module only Hafler is not responsible for consequential damages This warranty gives you specific legal rights You may also have other rights which vary from state lo state This warranty is void if acid core solder or paste flux has been used Hafler A Division Of Rockford Corporation 613 S Rockford Drive Tempe Arizona 85281 602 967 3565 HAFLER DH 500 STEREO POWER AMPLIFIER PICTORIAL DIAGRAM E Copyright 1983 All rights reserved REAR ah RF naD 3 7 N 4 TB 2 a gt A x ZZ Mi ee H OC OO OOOO Cs ui 120 Voit AC Line Connections Shown SERVICE POLICY AND LIMITED WARRANTY The DH 500 Power Amplifier has been carefully en gineered to provide many years of use without requiring any maintenance or servicing Factory assembled units are subjected to many physical
18. 6 T40 1 Power Transformer TAl16 TS40 I Thermal sensor SF025 T402 Power Transformer multi voltage TAl17 TS402 Thermal sensor SFO2S RY40 1 DPDT relay SZ113 Fan 120 volt AAli3 Fan 200 240 volt alternate AAI28 SAN TWA LNANOdWOD AC LINE CONNECTIONS FOR OVERSEAS USE The power transformer supplied in DH 500 amplifiers sold in the USA is intended for 120 volt 60 Hz operation only For use in other countries a multi voltage transformer is supplied in Export versions available at higher cost It has dual tapped primary windings which can be connected in series or parallel combinations for 100 120 200 220 or 240 volt 50 or 60 Hz power sources The connections which are different from the standard 120 volt connections described in the kit assembly instructions are all related to the transformer lead terminations and to the large resistors on the 7 lug terminal strip An additional 3 lug terminal strip is required when the 1402 100v 120V 200V 220V F404 T8401 o TB402 ome O DO BR 3 R411 Y BK K W 240V a ED a R412 U TS402 BX R e C408 1 401 BK multi voltage transformer is installed This the 600 ohm resistors the mounting hardware and the alternate line fuse are supplied in kits which include this transformer The diagrams below show pictorially and schematically the alternative wiring Only the pertinent wire connections are shown There are other wires connected to the 7 lug terminal strip which are
19. AP ULATIONS YOU HAVE COMPLETED ONE OF THE FINEST AUDIO AMPLIFIERS EVER DESIGNED ENJOY ITS SUPERB SOUND IF PROBLEMS ARISE If you are certain the problem lies in the power amplifier check first to see that the red pilot lamp is lighted If it is blinking at about 3 times a second this indicates that the thermal safety breaker on one channel has shut down the amplifier because of excessive temperature In this case the exhaust air will be warm After a few minutes of cool ing the amplifier will commence operation automatically If it shuts down again and the amplifier has sufficient ven tilation the malfunction is either internal or is the result of an excessive and possibly inaudible input signal If the lamp is not lighted at all the main fuse in the single fuse clip inside the chassis at the front is probably open If a replacement 15 ampere slo blo fuse also blows the amplifier needs service and there is a power supply prob lem If the relay will not close no signal at the output with an input signal check for excessive DC offset over 1 8 volts from either channel at locations 7 or 8 on PC 9 the small relay circuit board This indicates a defective amplifier channel reguiring competent service If there is no indication of excessive offset the fault is in the relay or on the PC 9 circuit board On rare occasions with some arm cartridge combina tions very high signal levels at subaudible frequencies may cause the
20. S Connect the other wire to the tip lug of RF S Make sure that all of the unconnected long wires except for the green wires to eyelet 7 on each board are placed off to the right so that when the module is installed on the chassis these wires will protrude between the feet below the right circuit board The wires to the 7 eyelets as well as those to eyelets 3 and 10 connect towards the front of the amplifier Carefully lift the module without touching the components on the circuit boards Swing it into posi tion on the chassis and check to make sure that no wires are trapped under the mounting feet Make sure that the input socket long lugs have not been bent so that any shorts are possible there or to the chassis Keep all wires away from the inrush limiter disc against the chassis It is a good idea at this time to check the fan by hand to make sure it rotates freely Shipping sometimes may cause a misalignment If it rubs bending a strut will correct the problem 78 L Select 4 sheet metal screws and secure the module to the chassis The easiest procedure may be to tilt the whole assembly backwards so that the module is again lying on the gasket giving you access to the bottom of the chassis Start the screws and then check again to make sure no wires are trapped be fore tightening the screws fully 79 L Select the green and white twisted pair from the bottom of the module Connect the green wire to the terminal st
21. THE natie FIER DH 500 INSTRUCTIONS for ASSEMBLY and OPERATION CAUTION IF THE FUSES BLOW SOME DISTORTED SOUND CAN BE HEARD THEREFORE IF AMPLIFIER MALFUNCTIONS ALWAYS CHECK FOR BLOWN FUSES FIRST LM153 Please refer to this serial 3 00 number in all communications regarding this eguipment THE DAVID HAFLER COMPANY 5910 Crescent Boulevard Pennsauken New Jersey 08109 DH 500 SPECIFICATIONS Power Rating Less than 0 025 total harmonic distortion at any power level up to 255 watts continuous average power per channel into 8 ohms at any frequency between 20 Hz and 20 kHz with both channels driven IM Distortion SMPTE Less than 0 007 from 1 watt to 255 watts into 8 ohms Typical THD at 255 watts into 8 ohms 1 kHz 0 002 10 kHz 0 007 Frequency Response into 8 ohms 3 dB 0 5 Hz to 120 kHz at 1 watt 0 5 dB 5 Hz to 40 kHz at 255 watts Typical Channel Separation at 1 kHz 60 dB Signal to Noise Ratio Exceeds 100 dB referred to 255 watts into 8 ohms unweighted Exceeds 90 dB referred to watt into 8 ohms A weighting Input Impedance 47 000 ohms Input Sensitivity 2 35 volts for 255 watts into 8 ohms 0 145 volts for 1 watt Damping Factor 200 to 1 kHz into 8 ohms 60 to 10 kHz into 8 ohms Rise Time 10 kHz 80 volts p p square wave 10 to 90 2 5 us Slew Rate 1 kHz 120 volts p p square wave 45 V us Semiconductor Complement 27 transistors 12 power Mosfets 33 diodes 8 zener di
22. aired and returned to you transportatiion prepaid and your 75 less the shipping charges will be returned to you If the problem is found to be an error in your assembly of the amplifier the amplifier will be put in proper working order tested to be sure it is meeting specifications and returned to you freight prepaid within the continental U S Excess shipping charges for expedited service or overseas delivery are your responsibility At the sole discretion of the factory service department if the time required for diagnosis repair and testing and the nature of the malfunction warrants it a portion of the submitted repair fee may be rebated This warranty is void if the kit has not been completely assembled or if other than rosin core solder has been used Units assembled with acid core solder or paste flux will be returned unserviced WARRANTY FOR FACTORY ASSEMBLED UNITS The DH 500 is warranted for three years from the purchase date including parts and labor and normal ship ping costs from the factory to the owner within the conti nental U S The owner is responsible for returning the unit to the factory and must submit a copy of the dated bill of sale This warranty gives you specific legal rights You may also have other rights which vary from state to state
23. and electrical tests before shipment The amplifier module assemblies of kit units are similarly tested to meet perfor mance specifications prior to packing In spite of this shipping damage does occur a kit may not be assembled properly or human error interferes so service may be needed The David Hafler Company provides complete service facilities at the factory to make any necessary re pairs Because many of the components in this refined de sign are not readily available through local sources and the performance of the unit is likely to be compromised with similar type substitutions we strongly recommend factory service or obtaining the requisite parts from the factory It is the owner s responsibility to return or ship the unit freight prepaid to the factory service department Units shipped freight collect will not be accepted For units to be repaired under warranty a copy of the dated bill of sale must accompany the unit Use the complete original carton and all packing mate rial to ship your amplifier Enclose with the unit the follow ing information Complete shipping address Post Office box numbers are not acceptable except for correspondence 2 The serial number if it is not on the unit 3 Copy of dated bill of sale if repairs are to be made under warranty 4 Description of the malfunction If intermittent be sure to so indicate 5 You may also wish to attach your address directly to the u
24. apability the result is complete freedom from listening fatigue The longer you listen to this re markable amplifier the more certain you will be that you could not have made a better choice While modest in cost through the elimination of frills and gadgetry the quality is evident not only in the sound but in the conservatively rated components The over sized power transformer the conservative operating levels of the MOSFETs the computer grade electrolytics total ling 40 000 microfarads the enclosed relay the use of film capacitors in signal circuits all are evidence of the design efforts to achieve exceptional reliability simultaneo usly with state of the art sonics and specifications So rugged is the DH 500 that it can deliver over 20 amperes into a short circuit For those with special power needs the DH 500 can be adapted to monophonic operation delivering in excess of 800 watts into 8 ohms by installing the DH 502 input bridging kit Those who have chosen to build this amplifier from the kit will find the assembly instructions assume no technical ability other than how to make a good solder connection Even that has been described for those who are new to the fun of kit building Through pre assembly and testing of the complete signal module the performance of the kit has already been assured for assembly involves little more than interconnection of the power supply and control ele ments You can look forward to jus
25. bie it to feed the complete amplifier When converted to monophonic operation the loudspeaker load is to be connected to the two centerred outputs only The right will act as the common and should be attached to the speaker _ This is what is known as a floating output for no connection is made to either black ground terminal It is sug gested that once the amplifier has been converted some clear KIT PARTS LIST PC 7 Board WP PC7 M ounting bracket SM BRT202 2 Screw Machine 4 40 x 5 16 HWH 145 2 Nut 4 40 KEP HWH 105 Wire Red 20 GA 3 0 Wire Green 420 GA 3 0 MAN Warranty Card LIT WAR 30 indication be made as to the appropriate connections and that be attched to the back panel Because of this floating output neither side of the output signal may be grounded such as thru a speaker switching box or head phone adapter that has a common ground between the left and right channels For equivalent load impedances the speaker fuses provide the same power output protection as in stereo operation but because of individual fuse variations only one fuse may blow at these levels It is best to replace both fuses if one blows asthe other may have been weakened These installation instructions designate connections in ac cordance with the DH 500 owner s manual and pictorial diagram and use the same terminology i e S indicates a soldercd connection B Ge R16 R2 R3 R13 os C3 01 a2 lt R
26. cessive heat sink temperature The fan will be operating at its highest speed and as soon as the heat sink temperature has declined the amplifier will automatically return to normal operation Such an occurrence is extremely unlikely and if the amplifier shuts down again and the lamp flashes you should check for inadeguate ventilation or an excessive input signal an extremely low load impedance or an input which may have dangerous signal content such as oscilla tion Failing evidence of this the fan or the amplifier may have malfunctioned Because of the very effective fan cooling any normal signal will not cause the amplifier to overheat At normal home use levels the average power con sumption is likely around 250 watts The units efficiency is about 50 so some full power tests may exceed the ca pacity of a 15 amp circuit When performing tests voltage losses due to long lines should be taken into consideration or compensated for Loudspeaker Fuse Selection The DH 500 is supplied with 2 ampere fuses in the speaker lines This conservative value has been chosen for initial use because most high guality speaker systems can not safely handle very high power levels even though a high power amplifier invariably makes them sound their best Since a substantial overload must continue for a few seconds before a fuse blows a 2 ampere fuse will allow very high power peaks to pass without hindrance yet will protect most speaker
27. crew will pass through a 6 nut aiding iden tification A set of hardware includes one screw and one KEP nut with its attached lockwasher Always install the lockwasher side of the nut first If the size of the hardware is not specified use the 4 size which is the smallest 10 is the largest Always insert the screw from the outside of the chassis 2L With the chassis upside down select the 4 rubber feet and 4 sheet metal screws The screw head re cesses fully into the foot Install these in the holes which are about I in from each corner 3 Select the AC line cord and the plastic strain relief Separate the two conductors of the cord for 2 in ches Strip 14 of insulation from each lead Twist the bare strands tightly and tin each lead 13 from the ends make a sharp V in the cord by bending it sharply back on itself Install the strain relief as shown with the small end of the strain relief nearest the stripped end of the line cord Crimp the two halves of the strain relief around the wire at the V with heavy pliers to partially form it before in sertion into the back panel Considerable squeez ing is necessary because the thick insulation pops back quickly Then grip the larger diameter of the strain relief with the tips of heavy pliers squeeze it tightly and insert the end of the cord through the back panel AC hole from the outside Note that the hole has two flat sides and the relief is s
28. d resistance to abusive operating con ditions at such high powers This is one of the direct ben efits of the power MOSFET s ability to current limit under abnormal conditions Where the conventional bipolar transistor must be pro tected by special circuits from entering thermal runa way when it gets hot due to heavy signals tending to get even hotter the MOSFET self corrects to reduce the cur rent and thus the heat under the same conditions You thus gain the dual advantages of simpler circuitry and the elimination of one of the chief causes for distorted signals imposed on the music the sound of the actuation of com plex protective circuits The speed measured as the slew rate of the DH 500 delivers unmatched transient linearity revealing the most delicate nuances of the music In refining the basic Hafler MOSFET circuit the overall open loop gain was reduced by using more local feedback in the input stage This re guired less compensation to stabilize the circuit with the result that it was faster overall With the built in bandwidth limitation at the input all other stages are free of any trans ient overload The fully complementary symmetrical push pull circuit is direct coupled throughout except at the input It uses all silicon discrete devices in a format which is directly re lated to the acclaimed Hafler preamplifier circuit With its unconditional stability into virtually any load and its enormous power c
29. ductors Never butter par tially melted solder on the joint as it is useless A good connection looks smooth and bright because the solder flows into every crevice when the parts are hot enough The iron must have a bright shiny tip to transfer heat eas ily to the junction That s why the damp sponge should be used freguently to wipe the tip and occasionally you must add a small amount of solder to the tip too If a connection Is difficult to heat wet the tip with a small blob of solder to provide a bigger contact surface to the Joint Once the solder flows around the conductors any movement must be avoided for a few seconds to allow a good bond When cool check the connection by wiggling the wire If in doubt or if the connection is not shiny re heat the joint Excess solder may be removed from a connection by heat ing it and allowing the solder to flow onto the iron which is then wiped on the sponge ALL SOLDER USED MUST BE ROSIN CORE Never use acid core solder or any separate flux in elec tronic work Silver solder is also not suitable If in doubt about unmarked solder always obtain a fresh supply of rosin core solder We recommend 60 40 for easiest use Do not confuse it with 40160 which is harder to melt The general procedure is to use a hot iron for a short time to heat a connection then add solder with the iron still in contact Remove the solder once it flows and then remove the iron A cooler iron appl
30. ecommended The unfamiliar user is more likely to damage the etched circuit boards with its higher heat potential and unbalanced weight Also because he may not wait long enough for it to reach operat ing temperature each time it is switched on poor solder connections are more likely Pencil irons are much lighter and easier to use and there is no waiting time when solder connections follow in sequence as in kit building Make sure you have a holder for it though and always unplug it when you take a break Proper Soldering There are four steps to making a good solder connec tion 1 Make a good mechanical connection to hold the wire in position while heat and solder is applied 2 Heat thejunction of the wire and lug or eyelet with the bright shiny tip of the iron 3 After heating for a couple seconds apply solder to the tunction It should melt immediately and flow smoothly around both surfaces SS 4 Allow the connection to cool undisturbed Remember that the connection is made by the solder not by mechanically attaching the wire to the terminal Usually the wire is looped through the lug and crimped in place but some prefer to just place it through the hole and rely on the stiffness of the wire to hold it while soldering Eyelet connections of course are handled this way Good solder connections are essential for trouble free noise free operation A good solder joint does not require much solder around the con
31. fd disc capacitor With the red window or on some switches the 3 lug or the separate lug of the switch to your right temporarily slide the white wire s spade lug part way onto the left switch lug Slide the line cord s spade lug part way onto the middle switch lug This simply makes it easier to attach the capacitor to these two spade lugs Cut each capacitor lead to one inch some freedom of movement is desirable wrap one lead around the shaft of each spade lug and solder each Then carefully disconnect the wires from the switch 99 _ Install the fuses The 15 amp slo blo fuse goes in the single fuse clip near the power switch The four 10 ampere fuses with the thicker elements go into the two dual fuse clips on the chassis If you have not already placed fuses in the speaker fuse holders on the back panel install the 2 ampere size for these will give good protection to most speakers A pair of 5 ampere fuses are also included for the speaker holders in the event your needs require very high powers However for steady state test signals at the full amplifier capabilities even larger fuse sizes will be needed in the speaker fuse holders Now you should make a last check of all the solder connec tions Look closely for possible bare wire shorts Check for secure hardware especially that on the output termi nals Check that wires are not lying on top of the power resistors on the 7 lug terminal strip Remove all pieces of
32. haped ac cordingly This is a very tight fit you will have to pull on the cord to help but it snaps into position when fully inserted 4 Select the two input sockets and 4 sets of hardware 5S 6 7 Ll 8 L Install the sockets at LS and RS inside the chassis so that the short lug is nearest the hole in the chas sis between the two sockets Select the single ground lug with lockwasher teeth and one set of hardware Install it between the input sockets Point it toward the bottom and bend it out for access Be certain this lug is tight The locking teeth must cut through the chassis paint for a good ground connection Select the two round fuse holders with caps and their 1 2 hardware rubber washers metal lockwashers and nuts First install the rubber washer on each holder so it will be outside the chassis and then fasten them at locations LF and RE The holes have flats which mate with the fuse holder to keep it from turning Point the tip lugs to wards each other Be sure all of this hardware is tight as it will not be accessible once the amplifier is completed Select the two red output terminals and their hardware the red washers 4 nuts without lockwashers and two plain connecting lugs Note that each part of the terminal has a flat which mates with the flat top of the chassis hole Install the ter minals in the two center holes LR and RR so that the washer flat is engaged tighten one nut securel
33. have included a pair of 5 amp fuses as alternates for temporary use as spares for testing the amplifier at very high power levels and for operation into very low load im pedances 5 amps will pass 80 watts into a 4 ohm load We suggest that you obtain additional type 3AG fuses of the appropriate size for your speakers Loudspeaker Power Ratings There are no U S standards for rating the power han dling capabilities of loudspeakers As a result the manufac turers usual music power ratings or suggested amplifier limits are of only minimal help in determining safe operating levels with amplifiers which can deliver enormous amounts of power On the other hand some speakers particularly tweeters can also be damaged through the use of too small an amplifier if it is driven into sustained clipping However tweeters are also more vul nerable to high level signals which are not always notice ably loud to the ear as from electronic music sources so you may wish to separately protect the tweeters with fuses of lower rating You must take into consideration the type of music and the levels you like to provide long term trouble free operation of your speaker choice when you have a very powerful amplifier like the DH 500 If more than one pair of speakers will be connected to the amplifier proper protection would dictate that each speaker be separately fused since when they are operated in parallel the combination of lower im
34. he 2 input soc kets 73 L Prepare a 14 black wire but strip 34 of insulation from one end Thread the longer bared end through the separate ground lug and connect it to the short ground lug of input socket RS Solder only the two wires at the center ground lug at this time Place the wire against the chassis and connect the other end to the bare wire between the two large capacitors S This is the 4th of 7 wires connected at this point Remember to leave space in the exact center for the last wire but keep all of these close to gether Now place the wired amplifier module behind the chassis in line with the input sockets so that it is resting on the foam gasket with the mounting feet against the chassis Its wires will protrude toward the chassis or to the right 12 74 O Select the yellow and black twisted pair from the left side of the module Connect the black wire to the short ground lug of input socket LS S 2 Connect the yellow wire to the long lug of LS S 75 Ll Select the red and black pair from the right side and connect the black wire to the short lug of input socket RS S 2 Connect the red wire to the long lug of RS S 76 J Select the twisted white pair from the left side Connect the longer wire to the side lug of the fuse holder LE S Connect the other wire to the tip lug of LF S 77 Ll Select the twisted white pair from the right side Connect the longer wire to the side lug of RF
35. hed to lug 3 S The proper way to connect one of the spade lugs to the wire is to bend the shorter wider set of tabs tightly around the bare wire and bend the outer longer set of tabs around the insulation Then flow solder into the joint around the bare wire 49 Ul Check both conductors of the power cord to see that they are tinned to secure every strand Con nect one lead of the power cord to FC lug 2 S 50 Select another spade lug and connect it to the free end of the power cord S 51 UU Prepare a 13 white wire Connect one end to the lower hole of LT lug 6 S Using the lower hole will make 1t easier for other wires to be connected to the same lug NOTE FOR MULTIVOLTAGE oprion This wire may need to be 1 longer and may connect to another termi nal for some line voltages 52 LJ Select the spade lug and connect it to the free end of the white wire from LT lug 6 Place this wire to the left and twist it lightly together with the green wire from LTlug 3 When connecting wires to the PC 9 circuit board note that the eyelets on this board are numbered in the reverse direc tion from the lug numbers on the terminal strip 53 U Prepare a 234 red wire Connect one end to PC 9 eyelet 8 S Connect the other end to relay RY lug 7 54 Prepare a 2 yellow wire Connect one end to PC 9 eyelet 7 S Connect the other end to RY lug 9 55 C Strip a 1 1 2 length of heavy wire bare Con
36. ialty speaker cables preferred by perfec tionists If you have 4 ohm speakers larger wire is recom mended than for the typical 8 ohm speakers too The black output terminals are connected to ground in ternally The black terminals may be connected together common ground when in the normal stereo mode to utilize headphone junction boxes or other accessories employing a common ground system ASSEMBLY There are three basic rules for success in electronic kit building 1 Read the instructions carefully and follow them in or der 2 Make secure solder connections which are bright and smooth 3 Check your work carefully after each step The DH 500 amplifier is a versatile component with sophisticated circuitry which has been made remarkably easy to build by individuals with many years ofexperience in the design and engineering of the finest performing audio kits and in the preparation of their manuals Kit building should be fun and we are certain you will find this to be so Assembly will be faster easier and more enjoyable if you have someone help you by reading the steps aloud selecting the required parts and preparing the necessary wire lengths in advance as you proceed Fatigue increases the risk of error so take a break rather than push to early completion There are relatively few separate components in this design to make it easy to pack every thing away if need be Your work area should have good lighti
37. ied for a longer time is more likely to damage components or lift the copper circuit pat tern from the boards A break in the etched circuit can be mended by simply soldering a small piece of wire across it Do not allow much build up of solder on the tip of the iron or it may fall into adjacent circuitry When soldering to an eyelet or hole on the board insert the wire from the components side and apply the iron to the bottom leaving some bare wire exposed so that you can see that the eyelet is then filled with solder for a secure bond A round wooden toothpick is suggested so that you can heat and clear an eyelet of solder if it hinders your in serting the wire Some builders prefer to clear every eyelet first with a touch ofthe iron and toothpick Others connect the lead by bringing it up to the center of the eyelet on top of the board applying the iron from the bottom of the board and pushing the lead in as the solder in the eyelet melts If the wire has first been tinned usually no addi tional solder is necessary but it is a good practice to push the wire through and then back it up a bit to be sure solder fills the eyelet On the bottom of the board make certain a bright shiny flow is evident from the wire onto the circuit pattern on the board Tinning refers to the process of applying a light coat ing of solder to the bared wire end This keeps all the strands secured and also makes a good connection easier S
38. imply touch the wire with the iron for a couple seconds and apply solder Allow the excess to flow away onto the iron When properly done the wire is uniformly bright and no larger than before The hookup wire supplied with this kit does not normally need tinning for it is pre tinned Wiring the Kit If any components are unfamiliar to you checking the pictorial diagram should guickly identify them Or the guantities and the process of elimination as you check the parts list will help The pictorial diagram is necessarily distorted to some extent for clarity so that you can trace every wire in a single overall view for verification as you work You may wish to check off on the diagram as you solder each location To prepare a wire means to cut the designated length from the coil of that color and strip about 1 4 of insulation from each end The wire supplied in the kit is 18 and 22 so you can set adjustable wire strippers accordingly The transformer leads are 18 and the line cord is 16 Be careful that you do not nick the wire when you strip it that can happen more easily if you do not use wire strippers for that weakens it The wire supplied in this kit is bonded stranded which provides exceptional flexibility with re sistance to breakage for easier use Whenever a connection is to be soldered the instruc tions will so state or indicate by the symbol S If more than one wire is to be soldered to the sa
39. in the DH 500 D7 D8 D9 and D10 prevent the gates of the MOSFETs from being overdriven in the event of abnormally high signal levels The B B and speaker fuses limit the maximum current in the outputs The thermal protection unlike most circuits does not interrupt the output of the amplifier If the heat sink temperature rises to 75 C the amplifier is turned off until it cools The relay circuit has a 3 section low pass filter which prevents signals above 10 Hz from opening the relay This circuit allows DC to pass to ICIOIA and ICIOIB which sense any offset above 1 8 volts opening the relay to protect the speakers DIOI RIO6 and R107 form the reference for the positive offset detector ICIOIA D102 R109 and RIIO form the reference for the negative offset detector ICIOIB C104 s charging time is the time delay at turn on and after any relay actuation FUNCTIONAL BLOCK DIAGRAM AMPLIFIER CIRCUIT CURRENT SOURCE Q Q7 Qg DIFFERENTIAL AMPLIFIER Q3 aa PASSIVE INPUT E FEEDBACK SIGNAL NETWORK DIFFERENTIAL AMPLIFIER Q 5 Q 6 PREDRIVER CURRENT SOURCE Q2 Q10 Q11 B PREDRIVER DRIVER OUTPUT O16 CLASS AB BIAS REGULATOR P Qg OUTPUT SIGNAL NEGATIVE OUT PUT NEGATIVE DRIVER RELAY CIRCUIT POSITIVE OFFSET LEFT LOW PASS FILTER NEGATIVE I OFFSET D ETECTOR IC B SPEAKER RELAY RELAY DRIVER Q
40. ingle hole between the two dimples at the front of the chassis The dimples prevent the clip from turning too far 15 Select the 2 dual fuse clips and 4 sets of hardware Install one of these in the pair of holes nearest the center of the chassis and the other in the pair of holes aligned with it near the left edge 16 LJ Select the 3 4 long 6 screw and a nut and the rec tifier diode block which has four lugs Install the rectifier DB in the front center hole nearest the fuse holders Note the lug positioning in the diagram and check the marked location of the lug 17 L Select the two round capacitor brackets the two large capacitors and 8 sets of 6 hardware Place a bracket around the bottom of each capacitor and fasten it with one set of hardware through each clamp Note the direction of insertion of the screw for easy servicing access in the future The clamp should be snug but not tight Place each assembly so the clamping screws are accessible from the front at locations CL and CR and secure each with 3 sets of hardware Then loosen the clamps and ro tate the capacitors so that each terminal is positioned as in the diagram Make sure the capacitors are seated against the chassis and tighten both clamps 18 L Select the 4 plain connecting lugs and four 1 4 long large screws with lockwashers attached Install these on top of the capacitors with the lugs pointing as in the diagram 19 LJ Select the two
41. ipment or if your control unit does not have the 15 ampere switching capac ity you should use the power switch on the DH 500 and connect it directly to the AC line In such use turn the amplifier on last and switch it offfirst This will avoid pos sible loudspeaker damage from turn on transients gener ated by source equipment A power transformer of this size puts out a noticeable hum field even though the special design of this trans former minimizes such radiation If the amplifier is to be installed close to a record player you should first check for freedom from hum pickup by the phono cartridge Some cartridges are much more sensitive than others and re quire more separation from the amplifier Check at a rela tively high volume setting while swinging the tone arm throughout its arc A few inches additional space will usu ally solve any problem Ventilation is most important Unobstructed air circula tion at the sides and back is important for long trouble free life A 3 speed fan operates at its lowest speed whenever the amplifier is turned on and is automatically switched to higher speeds at the power output demands it Air is drawn in at the sides and expelled to the rear With normal home music levels the cooling capacity is sufficient that the fan will rarely operate at other than low speed where it is so guiet that your ear must be close to a vent to hear it The front panel is designed to facilitate moun
42. kelihood of hum pickup They should cross AC cords at right angles never running parallel to AC lines at close range For professional applications the phono inputjacks may be easily replaced with 14 phone jacks Be sure in that case that they are grounded to the adjacent ground lug Output The loudspeakers connect to the red and black 4 way binding posts These are of a particularly heavy duty con struction to handle the high currents which may be in volved They are spaced for double banana plugs or you can connect stranded wire through the vertical hole in the shaft which is visible when the cap is unscrewed To be cer tain that no strands of wire are unsecured a tinned end or a spade lug soldered to the wire is recommended Be sure to maintain correct speaker phasing by watching the lead identification in the hookup wire and the identifi cation of the speaker terminals It is important that the sense of one speaker s connections match the others If the speakers are out of phase you will find that the sonic image has a hole in the middle and there will be a loss of bass This will be most evident on monophonic material Correct it by reversing the leads to one speaker Select speaker wire of sufficient size to preserve the high damping factor of the DH 500 Standard 18 gauge lamp cord is the minimum suggested and is suitable for short distances The next larger wire is 16 There are also a number of spec
43. me point they will be indicated by S 2 S 4 etc If soldering is not called for other connections have yet to be made to that termi nal They would be more difficult if the connection was al ready soldered Every connection in the kit will be sol dered when it is complete After soldering a connection it Is best to clip off any excess lead length to minimize the possibility of a short circuit as on switch lugs where ter minals are very close together and for neatness Be sure that uninsulated wires cannot touch adjacent terminals or the chassis metalwork The symbol mf indicates a connection is to be made to that point When a lug number is specified without ff it is simply a locating reference When the instructions call for twisting two or three wires together the length of wire indicated anticipates a fairly tight uniform twist by hand of three full turns every two inches If you find the wires too short loosening the twist will gain some needed length Handle the circuit boards carefully They represent a major part of the kit cost Stand up components such as transistors should be checked when you install the mod ule to be sure all leads are separated and that the large electrolytic capacitors have not broken loose from the board Take the time to be accurate and neat and you can be sure that your completed amplifier will meet the per formance of a factory assembled unit and can continue to perform pr
44. nect one end to large capacitor CL lug X2 S Connect the other end to CR lug 3 S Be very sure that these connections are well soldered because they will carry considerable current 56 Prepare an 812 red wire Connect one end to PC 9 eyelet 6 S 57 _ Prepare a 19 black wire Connect one end to PC 9 eyelet 5 S 58 LJ Prepare a 9 yellow wire Connect one end to PC 9 eyelet 4 S 59 Place the red black and yellow wires toward the left and twist them lightly together Keep these against the chassis and connect the red wire to dual fuse clip FR lug 5 Connect the yellow wire to FR lug 6 Connect the black wire to the center of the bare wire between the two capacitors CL and CR S Six other wires will be connected to the center of this bare wire The amplifier will have the lowest hum if the last wire to be connected from the transformer a heavy wire is placed in the exact center of this link between the two capacitors so leave a small space for it However all 7 wires should be connected as near to the center point as possible 60 Prepare a 41 2 red wire and connect one end to PC 9 eyelet 3 S 61 _ Prepare a 534 yellow wire and connect one end to PC 9 eyelet 2 S Place this wire and the red wire from eyelet 3 to the left Twist them lightly together and connect the red wire to RY lug B S Con nect the yellow wire to RY lug A S 62 _ Prepare a 3 white wire
45. ner Diode ODIlN R111 10 megohms RCOIS D103 IN4148 Diode QDI 16 R112 4 700 ohms RC042 D104 1N4148 Diode QD116 R113 10 megohms RCO18 D105 1 N4003 Diode ODI15 R114 1 megohms RC047 D106 1N4003 Diode ODI15 R115 10 000 ohms RC016 D107 1 N5240B I OV Zener Diode QDI1II R116 100 000 ohms RCO17 D108 1N5240B10V Zener Diode QDIII R117 150 000 ohms RCO2 I D40 1 I N4003 Diode QD115 R118 10 megohms RCOL8 Ol 2N540 1 OP122 R119 22 000 ohms RC026 Q2 2N5550 QN128 RI20 1 500 ohms 2 w metal film RZ015 Q3 2N5550 ON128 R401 470 ohms w RDI 17 Q4 2N5550 QN128 R402 470 ohms Y w RD117 Q5 2N540 QP122 R403 470 ohms Ya w RD117 Q6 2N540 1 QP122 R404 220 ohms 2 w RD114 Q7 2N540 1 QP122 R405 220 ohms Y w RD114 Q8 2N5415 QP123 R406 220 ohms Ya w RD114 Q9 NP2222A ON124 R408 1 megohms Y w RDI13 Q10 2N5550 QN128 R409 300 ohms 7 w RWO15 Ol 2N3440 ON125 R410 300 ohms 7 w RWOIS Q12 2N3440 QN125 R41 600 ohms 7 w RW024 Q13 2N5415 QP123 R412 600 ohms 7 w RW024 Q101 2N 5550 QN128 DB401 Diode Bridge QD117 Q401 2SK 176 QNI13 F40 Fuse 2A 3AG value optional SFOI 1 Q402 2SK176 ONI 13 F402 Fuse IDA GLH SFO13 4403 2SK176 ONI 13 F403 Fuse 10A GLH SF013 Q404 2S156 QPI 13 F404 Fuse 15A Slo Blo MDA SFO14 Q405 2SJ56 QPI 13 F405 Fuse 7A Slo Blo MDA SFO21 Q406 2SJ56 OP113 IC40 1 LM339N OBl15 S401 Power switch SLIL LI Inductor 1 4uH TAI12 TB40 1 Thermal breaker SF024 Pl 1000 ohms trimpot RPOII TB402 Thermal breaker SF024 P2 1000 ohms trimpot RPOII TR40 1 Inrush limiter RZO1
46. ng the proper tools and a place where the large pictorial diagram can be tacked to the wall within easy reach for checking The tools should include 1 A 40 to 60 watt pencil soldering iron with a 306 or smaller tip which reaches 700 F 2 60 40 60 tin ROSIN CORE solder 1 16 diameter or smaller 3 A damp sponge or cloth to wipe the hot tip of the iron It is important that the red terminals never be connected together when operating in stereo Thus it is important that you carefully observe the proper connections when using a common ground device to be sure there is no reversal In the special case where the amplifier has been inter nally modified to convert it to monophonic bridged opera tion with the addition of the DH 502 then only one input Jack is connected and the output is taken only from the two red terminals Such a floating connection must be maintained with no connection to the black terminals INSTRUCTIONS 4 A wire stripping tool for removing insulation This can be a single edge razor blade but inexpensive stripping tools are safer faster and easier A medium blade screwdriver about 1 4 wide A l or 2 Phillips head screwdriver Needle nose pliers a long narrow tip Diagonal or side cutting small pliers o o m DW Large gas or slip joint pliers 10 A 1 4 Spin tite nut driver may be helpful but is not necessary A soldering gun is mof r
47. nit or to the line cord All service work 1s guaranteed for 90 days Warranties apply to the original purchaser only The warranty is void 1f the amplifier has been modified without factory authorization or if parts have been substituted which in the factory s judgment are not suitable or if the amplifier has been either physically or electrically abused or used for some purpose for which it was not designed or intended The warranty on the transformer is void if the leads have been cut too short for re use If you think the transformer is defective unsolder do not cut the leads for its return Technical assistance to help you locate the source of a problem may be obtained by calling the Technical Services Department at 609 662 6084 8am 4 30 pm E T It is help ful to know the serial number of the unit and the results of any tests you have performed However we do not rec ommend that you attempt your own servicing unless you are knowledgeable in this regard 20 The weight of a DH 500 unless it includes the special multi voltage power transformer when packed exactly as it came from the factory should be just under 50 pounds and may be shipped by UPS However be certain it is fully protected and insure it for the full value If you choose it is possible to return only a portion of the amplifier for factory service with some disassembly on your part This assumes that you are certain the prob lem lies only in the re
48. odes one integrated circuit one diode bridge Power Consumption 240 VA quiescent 1200 VA rated power into 8 ohms 2 channels Size 7 1 4 high 19 wide 13 deep including handles Net Weight 45 lbs Shipping Weight 49 lbs CAUTION For continued protection replace the power fuse only with the same type and rating as indicated WARNING TO PREVENT FIRE OR SHOCK HAZARD DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE Copyright 1987 All rights reserved INTRODUCTION The Hafler DH 500 is a two channel audio power amplifier designed to the very highest performance stan dards It is available as a kit or factory assembled Its power rating of 255 watts per channel is very conservative and it can deliver appreciably higher powers into impe dances below the rated 8 ohms You must be very cautious in the application of this amplifier as its output capability is more than most speakers can safely tolerate We urge you to read the Operation section of this manual so your speakers will be reasonably protected The best protection is still common sense in choosing program levels which your speakers can tolerate The DH 500 combines power MOSFET technology with a uniquely simple and effective circuit which reduces all types of distortion at all power outputs over the entire audio spectrum to levels where the finest test equipment has great difficulty in measuring it The DH 500 sets a new high in reliability an
49. operly for years to come Check your work and make sure the entire step has been completed before plac ing a check mark in the space provided and continuing on to the next step MECHANICAL ASSEMBLY IL For security in shipping the power transformer and the amplifier module have been fastened to the chassis Remove the chassis cover the inner front panel and the larger front plate and set these aside Be particularly careful in handling the amplifier module to see that the leads of the upright compo nents on the circuit boards are not stressed This module accounts for more than half the kit cost and has already been thoroughly tested for specified performance before it was packed Turn the chassis upside down and rest it on the module and transformer to remove these parts In clude all of the hardware you have removed with the rest when you check off the components against the parts list in the back of this manual We recommend this check off to be sure you have ev erything and to enable you to identify any unfamil lar items by comparing them with the pictorial diagram Although the perspective of the diagram has sometimes been distorted to show connections more clearly it should enable you to recognize any unfamiliar component An egg carton is ideal for keeping small items like hardware at hand It will simplify matters if you first separate the 4 nuts from the 6 nuts which have the same outside dimen sions A 4 s
50. pedance and the higher power handling capacity would suggest a much larger fuse at the amplifier than would provide individual protection If full power tests are to be performed particularly at low load impedances fuse ratings above 10 amps may be reguired for the duration of the test CONNECTIONS AC The standard unit is intended for 120 volt 60 Hz opera tion If it is controlled by an AC switch on a preamplifier the DH 500 power switch may be left on If your line voltage is other than that provided in the United States be sure you have the alternate multi voltage power transformer and be sure it is wired for your mains voltage before you plug in the amplifier The connections for other line voltages will be found in the back of this manual Input Standard phono jacks are installed to accept conven tional shielded cables such as those supplied with your preamplifier Be sure that the outer shield connection is secure to avoid hum The length of these cables so as to permit remote location of the amplifier if desired is lim ited only by the output impedance of the preamplifier If it is 1000 ohms or less as with Hafler preamplifiers cable lengths of up to 100 feet are permissible without loss of per formance Special low capacitance cables enable even greater distance between preamp and power amplifier It is desirable to keep the left and right input cables close to gether throughout their length to minimize the li
51. rip LTlug ffl Connect this wire to the lower hole in that lug and solder 1t separately from the two wires which are soldered to the upper part of the lug Make sure all 3 wires are soldered Connect the white wire to LT lug 4 Use the lower hole for this wire and solder it separately now Do not solder the capacitor lead to the upper part of the lug at this time 80 O Select the triad of black red and yellow wires from under the module These will be connected to the right end of the terminal strip and to prevent the heat from the large resistors from melting the insu lation on the wires connect the wires from behind the terminal strip and keep them against the chas sis so the resistors will be above them Connect the black wire to LT lug 5 Connect the yellow wire to LT lug 6 Connect the red wire to LT lug 7 81 _ Select one of the 300 ohm 7 watt resistors Trim each lead to 3 4 Strip two 1 Z lengths of insulation from a piece of heavy wire and place one piece over each resistor lead as insulation Connect one lead to LT lug 5 on the front side of the strip Connect the other lead to lug 6 Because lug 6 will eventually have several wires it is important that each wire be placed as low as possible in the opening and crimped so as to maintain the largest possible opening for the last wire Tn these two steps use the 600 ohm resistors instead if the overseas multivoltage transformer option is wired for
52. stage Its power supply is a full wave bridge with 20 000 mfd capacitors on both the plus and minus supplies to provide excellent filtering and dynamic load stability Protection circuitry includes two separate power supply fuses for each channel individual thermal sensing devices for each channel to turn the amplifier off if the heat sinks should reach excessive temperature a relay to disengage the output if excessive DC offset is detected and output fuses to protect the speakers in ad dition to an AC line fuse Transistors 03 Q4 Q5 and Q6 the input differential pairs are matched to control the DC offset of the amplifier To optimize the input pair parameters they are driven from constant current sources l and O2 An adjustable voltage reference is formed by transistor Q9 and potentiometer PI Thus the signal sees the bases of transistors Ol2 and Q13 tied together Pl adjusts the voltage to bias the amplifier for Class AB operation and therefore determines the guiescent idle current in the driver and output stages Complete circuit stability is assured by the positive temperature coefficient of the power MOSFETs The driver and output stages of the DH 500 are of the full com plementary configuration Q14 QIS and Q16 are N channel MOSFETs in parallel for the positive half of the signal and Q17 Q18 and Q19 are P channel MOSFETs for the negative signal half There is none of the usual volt amp limiting
53. t secure the board to the outer surface of the bracket tabs 12 LJ Select the short twisted pair of wires connected to eyelets 4 and 6 Connect the red wire to the upper eyelet 1 of the right circuit board at the center rear S Connect the green wire to the lower eyelet 2 S 13 Place the long pair of wires from eyelets 1 and 3 down between the amplifier module mounting bracket and the back of the chassis The module can be tilted forward to facilitate this Connect the red wireto the lower ey elet 1 on the left circuit board S The easiest way is to wrap it in a tight loop around the bare stub of the wire presently connected to this eyelet Be sure both wires are soldered securely to he board Connect the green wire to the upper eyelet 2 in the same fashion S 14 1 Making sure that no wires are trapped by the mounting bracket reinstall the two screws securing the rear of the module to the chassis Tighten all 4 screws 15 0 Connect the red wire of the remaining twisted pair from PC 7A to eyelet 6 of the PC 9 circuit board behind the power trans former S This wire may be connecred to the stub of the existing wire as before Connect the green wire to eyelet 4 of PC 9 S Eyelei 1 of PC 9 is nearest the edge of the chassis 16 0 Reinstall the amplifier cover PC 7A PARTS LlST RI 22 1K 1 metal film RMP 4 2212 R2 2 2K 1 4w 5 carbon film RC 4 222 R3 2 2K 1 4w 5 carbon film RC 4 222 R4 47 ohms l 4w
54. t a few hours of con struction fun to hear the finest audio amplifier yet pro duced CONTENTS installation Page 4 Schematic Diagram 16 Operation 6 4 Component Values 17 Connections case Y Oo 5 AC Line Connections for Overseas Use I8 Assembly Instructions 6 Kit Parts List Le DE Do cea e I9 If Problems Arise 14 Service and Warranty 20 Circuit Description I5 Pictorial Diagram Insert INSTALLATION The DH 500 may be installed out of sight in many appli cations where its power can be controlled by the AC switching of a preamplifier control unit However any high power amplifier may draw enormous amounts of cur rent so you should make sure your preamplifier has the switching capacity for the amplifier s needs as well as any other eguipment which it also switches inadeguate switch current capacity may eventually render the switch in operative The power switches in Hafler preamplifiers have been chosen for their high ratings and have been tested and deemed suitable for normal home switching of the DH 500 However if the amplifier is intended for operation at sustained high power levels or where power switching is very freguent or where the control unit must switch sub stantial additional current for other equ
55. ting in a standard 19 rack Be sure all of the cover screws are instal led when the unit is supported by the front panel OPERATION The AC power cord should be plugged into a source of 120 volts 60 Hz unless the amplifier is specially provided with the multi voltage optional transformer Press the power switch to the right to turn the amplifier on A red pilot lamp in the power switch signifies that it is on If it is not illuminated the most likely cause is a blown AC line fuse That is the single fuse close to the switch inside the chassis However since the amplifier uses a 15 ampere slo blo fuse and the typical home circuit is also rated at 15 amps check that as well To avoid the turn on transients generated in many con trol units there is a 3 second delay before the relay con nects the speakers A few preamps may reguire a longer delay to avoid their internally generated turn on pulses Information on extending this turn on delay is available from the company on reguest A standard 2 wire power cord was chosen in preference toa 3 wire grounded AC cord because there is no signific ant current leakage in this design Where local reguire ments dictate the need for a 3 wire power connection a ground lug may be attached to the chassis adjacent to the AC line fuse holder If the pilot lamp should ever blink about 2 3 times a second this signifies that a protective thermal breaker has shut down the amplifier because ofex
56. transformer feet for stiffening Install the bolts near the edge of the chassis first That will determine which of the inner sets of holes are to be used It may be easiest for you to tilt the assembly up on its right side so the transformer weight is supported by the work surface or you can turn it upside down Be careful the transformer does not swing into the circuit board on the module Before you tighten any of the mounting bolts check to be sure the line cord and other wires are clear of the transformer feet 92 UU Connect the black lead to LT lug 4 S 3 One of these wires has most likely already been soldered to the lower hole of this lug 93 LJ Connect the black white lead to LT lug 6 S 4 One wire has most likely been soldered to the lower hole of this lug 94 Connect the red yellow lead to the center of the bare wire between CL and CR Be sure all 7 wires are well soldered 95 Connect one red lead to DB lug 1 Connect the other red lead to DB lug 4 96 LJ Prepare a 13 1 2 red wire Connect one end to PC 9 eyelet ffl S Place this wire down against the chassis and connect it to DB lug ml I3 97 J Select the Ol mfd disc capacitor and trim each lead to 3 4 Strip two 1 2 lengths of insulation from a piece of heavy wire and install these on the capacitor leads Connect one lead to DB lug ml S 3 Connect the other lead to DB lug 4 S 2 98 _ Select the power switch and the 005 m
57. turned portion and that you assume full responsibility for reinstalling it correctly since a ser vice warranty cannot be extended for other than the actual portion serviced Because the transformer is so heavy and a problem there is most unlikely its removal by unsolder ing a few leads is a logical choice The balance of the amplifier should be insured for at least 700 It is also pos sible to unsolder the module and return it if that is where the only problem lies However it requires much more care in packing to protect the delicate components on the circuit boards and many more connections must be unsol dered so there is more risk for reinstallation error It should be insured for 400 The service fee for the module is 50 If you return an amplifier for service or checkout and it is functioning correctly a charge will be made for the testing time required as well as for packing and shipping WARRANTY FOR KIT BUILT UNITS The parts in a DH 500 kit are warranted for a full year from the purchase date If a defective component is found on a circuit board or in a kit simply return the individual part to the factory prepaid together with the serial number and the date of purchase and it will be replaced at no charge If you cannot locate what is wrong with your DH 500 return it to the factory along with a copy of the dated bill of sale and a check for 75 If the cause of the problem is a defective part the unit will be rep
58. twistcd pair of leads from eyelets 1 and2 of the right amplifier module at the center rear of the amplifier This pair of leads which connects to the right inputocket will no longer be used while the amplifier is funtioning monophonically These leads must be taped securely so that there is no possibility for the bare wire to contact any portion of the circuit Masking tape is sufficient but electrical tape is preferred These leads may be removed if desired COMPONENT SIDE PC 7A 06 05 A e R2 a R 3 e Rito o R10 e e R12 e eo R5 e BUS R3 04 02 e R7 e e Ri1 R6 e e R9 e re C1 0 amp R6 e ecis nis A Me RN ZF ES 1 03 01 ie ne Ri6 10 Remove the rear rop screw securing the right channel amplifier 11 circuit board to the hear sink just above where the twisted pair was disconnected Do nor lose the fiber spacing washer which is between the circuit board and the heat sink This washer is not used on later production DH 500s Select one of the screws from the bridging kit and the mounting bracket The bracket is anchored at this location flat surface up with the screw inserted fust through the single tab from inside the bracket then through the circuit board the fiber spacing washer optional and into the heat sink Select the two screws and nuts and the circuit board PC 7A With the components facing ou
59. two gauges of wire supplied with the kit For connections which pass substantial current the heavier wire is used Other connections need only the lighter gauge wire Connect the wires to the bottom of the module from the right side 23 _ Prepare a 9 1 2 red wire and connect one end to TS2 lug 6 S 2 24 _ Prepare a 71 2 green wire and connect one end to TBI lug 1 S 2 25 L Select the inrush limiter which is a disc about the size of a quarter Trim the leads to 1 2 and connect it between TBI lug 2 and TB2 lug 3 Solder both lugs 26 _ Prepare a 712 white wire and connect one end to TB2 lug 4 S 27 _ Prepare a 1 1 4 black wire Connect one end to TSI lug 7 S Connect the other end to TS2 lug 8 28 LJ Prepare a 9 black wire Connect one end to TS2 lug 8 S 2 29 Prepare a 10 12 yellow wire Connect one end to TS lug 5 S 30 Twist the red yellow and black wires from TSI and TS2 together Also twist together the green and white wires from TBI and TB2 Place both of these wire groups off to the right of the module Then turn the module right side up with the fan away from you and the wires extending off to the left When soldering to eyelets holes on the circuit boards the wires will be connected to the outside top of the board but they must be soldered securely to the circuitry on the underside It is best to heat the eyelet on the inner surface while the
60. y add the lug pointing up and tighten the second nut Select the two black output terminals their hard ware and two plain connecting lugs Install them at LB and RB as in the previous step E bh NS ae PS Y i 5 S Nui A A gt a y 2 ae er 4 4 A 7 P f a sS E kue ea 2 y N y y ia Y S l r i TN y dit md ua lt lt a an ah Ba y gon L E 9 Select the plastic encased relay the longer L shaped mounting bracket and 2 sets of hard ware Insert the screws through the bracket with the bracket foot pointing away from the lugs at the opposite end of the relay lighten this hardware se curely but do not risk breaking the plastic 10 Select 2 sets of hardware and mount the relay near the 2 red terminals with the bracket facing front Install the screws from below the chassis 11 Select the 2 shorter L brackets 4 sets of hardware and the circuit board PC 9 Mount the brackets on the circuit side of the board with the feet pointing away from the board 12 Select 2 sets of hardware and install the circuit board between the line cord and terminal RB with the components facing to the rear 13 Select the 7 lug terminal strip and 2 sets of hardware Install it at the two inner holes in front of PC 9 The hole near the right chassis edge is not used The mounting feet face forward 14 L Select the single fuse clip and a set of hardware In stall it in the s

Hafler DH-500 Stereo Amplifier User Manual

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