Hafler DH-200 User Manual download pdf (Page 20)

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

(

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

FLzo17

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

DH-222

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Hafler DH-200 User Manual Page 20

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