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DH-222 INSTALLATION INSTRUCTIONS

Disconnect AC power from the amplifier, and remove all con-

necting cables. Wait 5 minutes to allow capacitors to discharge

before proceeding with disassembly.
Remove all 8 screws between the fins of each amplifier module

so that the cover may be removed, and the modules tilted out-

wards for easier access.
Unsolder the pair of twisted wires connected to holes 1 and 2 at

the top of the 

right 

channel PC-19 circuit board. The right

channel is the one nearest the power switch. This pair must

also be unsoldered from the right input socket on the back

panel, because it will be more convenient to use lighter gauge

wiring.
Prepare a 6%” red wire, and a 6 1/2" black wire. Start with the

black wire 1/2"”longer than the red wire, and twist them together

uniformly throughout their length. At the end where the black

wire projects, connect it to the 

short 

lug of the right input sock-

et. (S-2). Be sure the existing wire to the adjacent ground lug is

properly connected. Connect the corresponding end of the red

wire to the long lug of the input socket. (S). Place this pair off to

the right edge.
Prepare a 5%” red wire, and a 5%” black wire. With the ends

even, twist these together and connect ,the red wire to hole #l

at the top of the right channel PC-19 circuit board. 

(S)

 Connect

the black wire to hole #2. (S).
Prepare a 20”green wire. Cut a 20” black wire, but remove the

insulation from only one end. Starting with the bare end of the

black wire 1/2”longer than the green wire, twist these together.

At the far end, where the black insulation has not been re-

moved, the black wire will not be connected, but instead will be

secured by wrapping it in a tight circle around the green wire a

short distance from the bare green end. It is very important

that no bare wire be visible from the black insulation. The

single green wire is to be connected near the center of the lefi

circuit board to the hole designated “B”, located just below the

bias adjustment potentiometer. t

 S).

 It must be securely sol-

dered, but be careful that you do not damage adjacent compo-

nents.
Making sure that no wires are pinched between the module

and the chassis in the process, reinstall the left module to the

chassis with 4 sheet metal screws.
Select the switch and its 2 nuts, lockwasher and indexing flat

washer, and the switch mounting bracket. Install one nut all

the way onto the switch collar, and follow it with the indexing

washer with its lugprojecting towards the handle lever. Mount

the switch on the bracket so that the lever points in the direc-

tion of the bracket flange, and the indexing lug engages the

locating hole in the bracket. Secure it with the lockwasher and

the second nut.

9

 Select the two machine screws and nuts, and install the switch

bracket between the two transistors at the rear of the right

module, so that the switch lever points towards the fins.

10

 Select the 3000 ohm resistor and trim its leads to  1/2" Connect it

between switch lugs #4 and #5. Solder only lug #5.

11   Select the red and black pair from the right input socket and

12

 

13 

I4 

I5 

16 

connect the black wire to switch lug #3. Do not solder this con-

nection yet. Connect the red wire to switch lug #1. (S).

Select the red and black pair from the right channel circuit

board holes 1 and 2. Connect the black wire to switch lug #3.

(S-2). Connect the red wire to lug #2. (S).

Select the green and black pair and separate the wires for

about 1%“. Connect the green wire to right circuit board hole

“A”. (S).  Connect the black wire to hole “E”. (S). Hole “A” is

located in line with the switch about 1 1/2” from the rear edge of

the board. “E” is located 

1/2”

 below hole 2, near the top of the

board.
Place the green and black pair towards the rear of the module,

and down past the midline of the switch. Where it passes lug

#5, approximately 

 the end of the wires, cut 

only 

the

green wire. Strip each end 1/4" Connect the short green section

to switch lug #4. (S-2): Connect the longer green wire from the

left board to switch lug #6. (S).

Be careful no wires are pinched as you reinstall the right mod-

ule to the chassis with 4 screws. Place the long green and black

pair under the rear lip of the chassis. The pairs to the top

eyelets on each board, and to the connections in the center of

the board should be kept at least   off the board, where they

are clear of the components. Make sure the unconnected black

wire end near the left circuit board cannot touch any compo-

nents.
The switch lever should be placed in the upper position for

monophonic operation. In the lower switch position, the

amplifier functions as a conventional stereo amplifier. Rein-

stall the amplifier cover with the remaining 8 screws.

Содержание DH-200

Страница 1: ...SEMBLY CAUTION IF THE SPEAKER FUSES BLOW SOME DISTORTED SOUND CAN BE HEARD THEREFORE IF AMPLIFIER MALFUNCTIONS ALWAYS CHECK FOR BLOWN FUSES FIRST serial number in all communications THE DAVID HAFLER COMPANY 5910 Crescent Boulevard Pennsauken New Jersey 08109 ...

Страница 2: ...e made a better choice The oversized power transformer and bridge rectifier the massive heat sinks the conservative operating levels of the MOSFET output devices all are evidence of the design efforts to achieve exceptional reliability simultaneously with state of the art sonics and specifications And this circuit is convertible to a high power monophonic amplifier with comparable stability and sp...

Страница 3: ...l content such as oscillation Failing evidence of this the amplifier may have malfunctioned Because of the very large heat sinks it is highly unlikely that any normal signal will cause the amplifier to overheat Loudspeaker Fuse Selection The DH 220 power amplifier is supplied with 2 amp fuses in the speaker lines Experience has shown that since an overload must exist for a few seconds for a fuse t...

Страница 4: ...s been internally modified for monophonic bridged operation the output is taken from the two red terminals only Then the black terminals are left unconnected Headphones are normally operated from the loudspeaker outputs but are usually connected through a junction box which provides switching from phones to speakers Such a box usually provides some added resistance to reduce the sensitivity of the...

Страница 5: ...bond When cool check the con nection 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 heating 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 electronic work Silver solder is also not suitable ...

Страница 6: ...lements is left to the builder Take the time to be accurate and neat and you can be sure that your completed amplifier will meet the performance of a factory assembled unit and can con tinue to perform properly 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 KEP nuts have been s...

Страница 7: ...front The switch snaps into chassis hole PS from the outside 13 q Select the AC line cord and the plastic strain relief Separate the two conductors for 2 Cut 1 off one of the two leads and strip 1 4 of insulation from each lead Twist the strands tightly and tin each end Make a sharp V in the cord 81 2 from the longest cut end by bending it back on itself Install the relief with the small end neare...

Страница 8: ...uter tabs while the wire does not protrude into the spade clamp area Tin the bare wire end Bend the shorter middle set of tabs tightly around the bare wire and then bend the longer tabs around the insulation Then flow solder into the joint around the bare wire keeping the solder away from the spade section 29 Prepare a 2 white wire Connect one end to FC lug 2 S Select another spade lug and solder ...

Страница 9: ...dered You will be making con nections from the top side to holes 3 5 6 7 8 and 10 Make sure the proper connection point is clear at each of these If it is filled with solder running the iron along the underside will uncover the hole and it may be cleared with a wooden toothpick Now position the right module with the breaker at the front when the long bottom row of eyelets is next to the chassis wi...

Страница 10: ...terminals and the ground lug should be brought together through most of their length 68 Check all your soldered connections especially those on the fuse clip lugs which are sometines difficult to solder to Clip off any excess bare wire which could short to adjacent lugs or the chassis Pay particular attention to the stranded wires from the transformer and line cord and check the power switch conne...

Страница 11: ...lp you locate the source of a prob lem may be obtained by calling the Technical Services Depart ment at 609 662 6084 8 a m 4 30 p m E T It is helpful to know the serial number of the unit and the results of any tests you have performed SERVICING AN AMPLIFIER MODULE If you are certain that the problem is confined to one of the amplifier modules comprising the circuit board heat sink and output tran...

Страница 12: ...uired when the multi voltage transformer is used This is supplied in kits which include the special transformer If the amplifier is operated with 200 to 240 volt tines the 7 amp line fuse which is supplied should be replaced with a 4 amp Slo Blo type fuse n VOLTAGE CHART measured with 120 volt line no signal with respect to the ground buss between the two capacitors in the power supply E B c E B c...

Страница 13: ...3 XA012 XA014 XPO14 WA016 AH326 XKOll XK012 SLlll HR144 XK018 XK016 TA123 Hardware Envelope 1 Lug solder type internal tooth 6 4 Lug solder type lO 3 Lug spade l 4 12 Nut 4 40 KEP 11 Nut 6 32 KEP 4 Nut l0 32 KEP 2 Nut l 2 for fuse holder 12 Screw machine 4 x 5 16 10 Screw machine 6 x l 2 4 Screw machine l0 x l 2 4 Screw l0 x l 4 SEMS 16 Screw sheet metal 6 x l 2 1 Screw machine 6 x 3 4 4 Washer fl...

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Страница 15: ...36 RZo13 RMo21 RM013 RC023 RC053 RZOll RZOll RD114 RDl15 RC013 RW012 RW013 RM053 RDll7 RDI 17 RDll4 RDl14 RDI 13 CP115 CP134 CP135 CP136 CP136 CC125 CC125 CN113 CP133 CP134 CP135 CL122 CP135 CL122 CP135 CP135 CP133 CP135 CP135 CC125 C22 C23 C40 1 C402 C403 C404 C405 C406 C407 C408 Dl D2 D3 D4 D5 D6 D7 D8 D9 DlO Dll D12 D13 D14 D15 D16 D40 1 0 1 mfd lOOV Film 0 1 mfd lOOV Film OOl mfd 25OV Film 680...

Страница 16: ... IO kHz 0 007 20 kHz 0 012 Frequency Response into 8 ohms 3 dB 2 Hz to 160 kHz at 1 watt O 0 5 dB 6 Hz to 60 kHz at 1 15 watts Rise Time 10 kHz 60 volts peak to peak square wave 10 to 9 0 2 5 us Slew Rate 10 kHz 60 volts peak to peak square wave 30 VI s Semiconductor Complement 26 transistors 8 power Mosfets 29 diodes 4 zener diodes 1 diode bridge Typical Channel Separation 20 Hz 75 dB 1 kHz 85 dB...

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Страница 20: ...The amplifier circuit can safely accommodate lower impedance loads of course The conversion which takes less than an hour involves only changes to the input wiring and installation of the switch with its mounting bracket and one resistor These instructions assume familiarity with the usual kit building descriptions and reminders For more details in this regard see the con struction section of your...

Страница 21: ...tal screws Select the switch and its 2 nuts lockwasher and indexing flat washer and the switch mounting bracket Install one nut all the way onto the switch collar and follow it with the indexing washer with its lugprojecting towards the handle lever Mount the switch on the bracket so that the lever points in the direc tion of the bracket flange and the indexing lug engages the locating hole in the...

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