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INSTRUCTIONS FOR

THE HAFLER 

DH-222

 AMPLIFIER BRIDGING KIT

FOR THE DH-220

The DH-222 may be installed in a Hafler DH-220 power

amplifier to enable easy conversion to a high power

monophonic amplifier, bridging the two conventional chan-

nels to a single floating output which can deliver in excess of

400 watts into an 8 ohm load. Its rated power output is 350

watts across the audio band.

When switched to monophonic operation (UP), signal input

should be provided to the LEFT  input jack only, and the output

should be connected only to the two center BED 

( +)

 terminals.

No connection of the load is to be made to the black output

terminals. Because of the floating output, neither side of the

load may be grounded. Thus it is unlikely that stereo speaker

switching boxes, or headphone adapters may be used, as these

often have a common ground between the left and right chan-

nels.

The speaker fuses may be replaced with higher values than

the 2-5 ampere range suggested for stereo operation, if de-

sired, depending on the degree of protection for the speaker

which is intended. The graph shows the nominal sustained

power output limit of a 7 ampere standard fuse, which is the

maximum recommended value. Smaller values will provide

more protection for the speakers; larger ratings are at the

user’s risk.

fuse blows in mono operation, both should be replaced, for it is

likely that the second has been weakened. For equivalent load

impedance, each speaker fuse provides the same power output

protection as in stereo operation.

With the internal conversion switch DOWN, the amplifier

functions as a conventional stereo amplifier, with normal

input and output connections. The minimum recommended

load impedance, which is limited only by thermal factors (abil-

ity of the heat sinks to dissipate high energy levels), is 6 ohms

in mono; the usual 3 ohms in stereo. 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 DH-220 amplifier manual. You must

be certain you have made a good solder connection wherever

one is called for, not only to the wire you have attached, but to

any others already connected to that point. The notation (

 S)

indicates a soldered connection; (S-2) denotes that there are

two wires to be soldered. Use only 60/40  rosin core solder. Be

careful not to let the soldering iron touch adjacent components

on the circuit board: excessive heat could change their opera-

Both speaker fuses should be the same value. If one speaker tion, with the possibility of damage to the amplifier.

KIT PARTS LIST

Switch, DPDT

Mounting bracket

Indexing washer

Lockwasher

Nut, switch mounting

Nut, 6-32 KEP

Screw, machine, 6-32

Resistor, 3000 ohms

Wire, red, 22 gauge

Wire, green, 22 gauge

Wire, black, 22 gauge

sz114

MS183

HW123

HW122

HK125

HK112

HA116

12 16

RESISTIVE LOAD IMPEDANCE   

LIMITED WARRANTY

The 

parts in the DH-222 are guaranteed against defects for one year from the date of purchase. Installation in a DH-220

amplifier is the owner’s responsibility. In the event of difficulty with the completed unit, charges for service, if any, will be in

accordance with the warranty provisions for the amplifier, if it was purchased as a kit. If it was purchased as a factory

assembled unit, there is the further stipulation that faults incurred as a result of improper installation of the DH-222 are the

owner’s responsibility, but in other respects the original warranty applies. This warranty gives you specific legal rights. You

may also have other rights which vary from state to state.

5910 CRESCENT BOULEVARD, PENNSAUKEN, NJ 08109.609/662-6355

LM056

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...

Страница 14: ......

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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