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THE
AMPLIFIER
POWER
INSTRUCTIONS
for OPERATION
and KIT ASSEMBLY
CAUTION:
IF THE SPEAKER FUSES BLOW,
SOME DISTORTED SOUND CAN BE
HEARD. THEREFORE IF AMPLIFIER
MALFUNCTIONS, ALWAYS CHECK
serial number in all communications
FOR BLOWN FUSES FIRST.
THE DAVID HAFLER COMPANY
5910 Crescent Boulevard, Pennsauken, New Jersey 08109
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INTRODUCTION The Hafler DH-220 is a two channel audio power amplifier The oversized power transformer and bridge rectifier; the designed to the very highest performance standards. It is massive heat sinks; the conservative operating levels of the available either as a kit, or fully assembled. Its 115 watt per MOSFET output devices - all are evidence of the design efforts channel power rating is sufficient for driving all loudspeakers in to achieve exceptional reliability simultaneously with stat
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INSTALLATION The DH-220 is most likely to be installed out of sight in most than others, and require separation from the amplifier. Check at applications, since its power may be controlled by the AC a comparatively high volume setting, and while swinging the switching of most audio preamplifiers, like the Hafler DH-110. If tone arm throughout its arc. Often a few inches additional spac- your control unit does not provide switching capacity sufficient ing will eliminate the problem. for the ampli
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plugs are used, be sure they are color coded, or that you follow performance. Special low capacitance cables enable even the indexing mark on one side of the double connectors. greater distance between preamp and amplifier. It is desirable to keep the left and right input cables close together throughout their length to minimize the likelihood of hum pickup. Also, you Select speaker wire of sufficient size to preserve the high should avoid running them parallel to AC cords - these should damping
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A soldering “gun” is not recommended. The unfamiliar user is few seconds to allow a good bond. When cool, check the con- more likely to damage the etched circuit boards with its higher nection by wiggling the wire. If in doubt, or if the connection is heat potential and unbalanced weight. Also, because he may not shiny, re-heat the joint. Excess solder may be removed from not wait long enough for it to reach operating temperature each a connection by heating it and allowing the solder to flow on
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find it easier to first start them with a regular screwdriver, to set Wiring the Kit the thread, and then use the more convenient nut driver, if one is available. If any components are unfamiliar to you, checking the pic- torial diagram should quickly identify them. Or, the quantities, and the process of elimination as you check the parts list, will help. The pictorial diagram is necessarily distorted to some ex- Mechanical Assembly tent for clarity, so that you can trace every wire in a single
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5 n Select the two round fuse holders, and two each 1/2” rub- Connect the shorter lead to FC lug #l. (S). Connect the longer lead to the lower hole of TS lug #2. (S). Note that ber washers, lockwashers and nuts. First install the rub- ber washer on the holder, so it will be outside the chassis, lug 2 is the second protruding lug on the terminal strip. It and then fasten the fuse holders at LF and RF, with the is not the mounting bracket for the terminal strip. tip lugs pointing towards each othe
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shorter, middle set of tabs tightly around the bare wire, 19 c3 Prepare a 7” green wire. Connect one end to terminal and then bend the longer tabs around the insulation. LB. (S-2). Place this wire towards the center of the Then flow solder into the joint around the bare wire, chassis. keeping the solder away from the spade section. 20 Ll Prepare a 10” white wire and a 10” green wire. Starting 29 Prepare a 2” white wire. Connect one end to FC lug #2. with the white wire 3/4" longer, twist them
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these. If it is filled with solder, running the iron along the The transformer leads may be trimmed as desired for a neat job, underside will uncover the hole, and it may be cleared but be sure you do not cut any of them too short (particularly if with a wooden toothpick. yours is the multi-voltage version, and any change to a different supply voltage is likely). Cutting the leads too short for re-use Now position the right module (with the breaker at the may void its warranty, if it is thought
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55 I Select the white pair of wires at the front of the chassis. green ground leads from the black output terminals and Tuck the excess-wire into the corner and connect one the ground lug should be brought together through most wire to each of the lugs on the thermal breaker. Solder of their length. each. 68 Check all your soldered connections - especially those on the fuse clip lugs, which are sometines difficult to 56 [ Select the left output module, check it as before to see solder to. Cli
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Bias The transformer warranty is void if the leads have been cut Remove the B + fuse F2. This fuse is in the line from the ’ +’ too short for reuse. If you think a transformer is defective the capacitor terminal to hole #3 on the board. Connect an leads must be unsoldered, not cut, for its return. ammeter ’s ' + ' !ead to the fuse clip nearest the large filter capacitors. Connect the’ -’ lead to the other side of the fuse clip. Technical assistance to help you locate the source of a prob- Avoid
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The power transformer supplied in DH-220 amplifiers sold in the lJSA is intended for 120 volt, 60 Hz operation only. For use n in other countries, a multi-voltage transformer is available at higher cost. It has dual tapped primary windings which can be arranged in various series-parallel combinations for 100, 110, 120, 200, 220 and 240 volt 50 or 60 cycle AC mains. The schematic diagram details the wiring combinations which are represented pictorially here. Note that a separate 2-lug terminal st
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Fuse Envelope KIT PARTS LIST Part No. 6 Fuse, 5 ampere SF012 Minor variations may sometimes be encountered in value 2 Fuse, 2 ampere SF01 1 or appearance. These will not affect performance. 1 Fuse, 7 ampere, Slo-Blo SF02 1 1 Additional fuse, 4 ampere, Slo-Blo (International use only) SF026 Part No. Hardware Envelope Part No. 1 Chassis MS149 Cover 1 Lug, solder type, internal tooth, #6 HZ1 15 1 MS152 2 Capacitor. 10,000 mfd, 75V CL121 4 Lug, solder type, #lO HZ1 16 2 Bracket, round, for capacitor
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COMPONENT VALUES All resistors are l/4 w carbon film unless specified otherwise Part No. C21 0.1 mfd, lOOV, Film CC125 Rl 470,000 ohms RC044 0.1 mfd, lOOV, Film C22 CC125 1,800 ohms RC023 R2 C23 .OOl mfd, 25OV, Film CP136 R3 47,000 ohms RC043 C40 1 680 pF, 5OOV, Mica CM121 R4 47,000 ohms RC043 C402 0.1 mfd, lOOV, Film CE115 R5 1,000 ohms RC015 C403 10,000 mfd, 75V, Electrolytic CL121 R6 1,000 ohms RC015 C404 10,000 mfd, 75V, Electrolytic CL121 R7 47,000 ohms RC043 C405 .Ol mfd, lOOOV, Disc CZI
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SPECIFICATIONS Power Rating: Less than 0.02% total harmonic distortion at Input Impedance: 47,OOO ohms. any power level up to 115 watts continuous average power per channel into 8 ohms at any frequency between 20 Hz Input Sensitivity: 1.55 volts rms for 1 15 watts into 8 ohms. and 20 kHz with both channels driven. IM Distortion (SMPTE:) Less than O.OOS’%, from 1 watt to 1 15 Damping Factor: 300 to 1 kHz z into 8 ohms watts into 8 ohms. 60 to 10 kHz z into 8 ohms Typical THD at 115 watts into 8 o
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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 fuse blows in mono operation, both should be replaced, for it is amplifier to enable easy conversion to a high power likely that the second has been weakened. For equivalent load impedance, each speaker fuse provides the same power output monophonic amplifier, bridging the two conventional chan- nels to a single floating output which can deliver in excess of protection as
