Instruction/ maintenance manual of the product DH-500 Hafler
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_^.,_.. ._.. ,..-I_ THE POWE R AMPLI FIER 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.
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.
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.
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.
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.
number of specialty 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.
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.
MECHANICAL ASSEMBLY 1 0 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.
90 10 11 12 Selec t 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.
There are two gauges of wire supplied with the kit. For While excessive heat or careless “ scrubbing ” with the iron connections which pass substantial current, the heavier can lift the circuit foil from the board, more people tend to wire is used.
40 0 Prepare two 9 ” white wires. Connect one to eyelet 5 2 q Select the spade lug and connect it to the free end of #8 of the left board. (S). Connect the other to the white wire from LT lug 6. Place this wire to the eyele t #6. (S). Bend these toward the bottom, and left, and twist it lightly together with the green wire twist them together.
62 0 Prepare a 3 ” white wire. Connect one end to RY lug #4. (S). Connect the other end to red output termi- nal LR. (S). 63 [7 Prepare another 3 ” white wire. Connect one end to RY lug #6. (S). Connect the other end to output terminal RR. (S). 64 0 Prepare a 16 ” green wire.
80 0 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 meltin.
97 0 Select the .Ol mfd disc capacitor and trim each lead t o 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 #l. (S-3). Connect the other lead to DB lu g #4.
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.
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All resistors are ‘1’4 watt 5% carbon film unless otherwise noted. part N,,. Rl R2 R3 R4 R5 R6 R7 R8 R9 RIO RI1 RI2 RI3 RI4 RI5 R16 RI7 RI8 RI9 R20 R21 R22 R23 R24 R25 R26 R27 R28 R29 R30 R31 R32 .
A C LINE CONNECTIONS FOR OVERSEAS USE Th e power transformer supplied in DH-500 amplifiers sold in multi-voltage transformer is installed. This, the 600 oh m the USA is intended for 120 volt , 60 Hz operation only.
KIT PARTS LIST SMALL PARTS ENVELOPE 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. 2 1 1 Bracket, L-shape, 2 ” Bracket, L-shape, 3 ” Capacitor, 0.
DH-502 INSTALLATION INSTRUCTIONS 1. 3 2. 3 3. cl 4. El 5. 6. 0 7. 8. c! 9.3 Disconnec t AC power from the DH-500 and remove al l connect- ing cables. Remove the 1 7 screws which secure the cover along the top front, sides and rear. Set cover aside. DO NOT GRAB THE AMPLI- FIER PANEL OR HANDLES WHEN TH E COVER IS RE- MOVED.
INSTRUCTIONS FOR TH E HAFLER DH-502 AMPLIFIER BRIDGING KIT FOR THE DH-500 The DH-502 Amplifier Bridging Kit for th e DH-500 consists of a PC-7A circuit board comprising a 6 transistor phase inverting amplifler, a mounting bracket, necessary hardwareandconnecting wire.
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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 and electrical tests before shipment. The amplifier module assemblies of kit units are similarly tested to meet perfor- mance specifications prior to packing.
An important point after buying a device Hafler DH-500 (or even before the purchase) is to read its user manual. We should do this for several simple reasons:
If you have not bought Hafler DH-500 yet, this is a good time to familiarize yourself with the basic data on the product. First of all view first pages of the manual, you can find above. You should find there the most important technical data Hafler DH-500 - thus you can check whether the hardware meets your expectations. When delving into next pages of the user manual, Hafler DH-500 you will learn all the available features of the product, as well as information on its operation. The information that you get Hafler DH-500 will certainly help you make a decision on the purchase.
If you already are a holder of Hafler DH-500, but have not read the manual yet, you should do it for the reasons described above. You will learn then if you properly used the available features, and whether you have not made any mistakes, which can shorten the lifetime Hafler DH-500.
However, one of the most important roles played by the user manual is to help in solving problems with Hafler DH-500. Almost always you will find there Troubleshooting, which are the most frequently occurring failures and malfunctions of the device Hafler DH-500 along with tips on how to solve them. Even if you fail to solve the problem, the manual will show you a further procedure – contact to the customer service center or the nearest service center
