Hafler DH-200 Instruction Manual

THE

POWER

AMPLIFIER

DH-200

INSTRUCTIONS

for

ASSEMBLY

and OPERATION

929204

$3.00

THE

DAVID

HAFLER COMPANY

5910 Crescent Boulevard, Pennsauken,

New

Jersey 08109

Please

refer to this serial

number in all communications

regarding this equipment.

INTRODUCTION

The

Hafler

DH-200 is a two channel audio power amplifier

designed to the very

highest

performance standards. It is

available either as a kit, or fully assembled. Its 100

watt

per

channel power rating is sufficient for

driving

all

loudspeakers in home applications, and its design provides

extremely low distortion of

all

types. A combination of high

performance,

dependability and reliability, and moderate

price

is in the

Hafler

tradition of using the

latest

technology

to provide outstanding value.

Combining

the

latest

power

MOSFET

technology with

uniquely

simple

and

effective

circuit

topology reduces distor-

tion of all types, and at all power

levels,

over the

full

audio
frequency spectrum, to the vanishing point. In addition to its
pace-setting performance achievements, the conservative
mode of operation accomplishes a new high in long term
reliability

and exceptional resistance to abusive operating

conditions.

This

is one of the direct

benefits

of

MOSFET

utilization

in overcoming a serious limitation of conven-

tional

transistors — their tendency to self-destruct under
other than normal operating conditions. So rugged is the
DH-200

that it can deliver as much as ten amperes into a

short circuit!

The

speed — measured as the

slew

rate — of this design
delivers unmatched transient linearity, revealing the most
delicate shadings,

textures

and nuances of the music, surpass-

ing

the capabilities of the most revealing loudspeakers and
cartridges by a wide margin. Coupled with its unconditional
stability, and ability to deliver adequate power into any
loudspeaker load, the result is absolute freedom from listen-
ing

fatigue. The longer you listen to this phenomenal
amplifier,

the more certain you will be that you could not

have made a better choice.

Though

modest in

cost,

the DH-200

evidences

the very
finest electrical and mechanical design. It avoids costly frills
and

unnecessary gadgetry while

providing

quality sound and

reliability

based on top grade components conservatively

operated.

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 (with an internal accessory bridging circuit
board)

to a high power monophonic amplifier with

equivalent stability and specifications.

The

fully complementary, symmetrical push-pull circuit,

which

is direct coupled throughout

(except

at the input), in-

corporates all silicon

devices

in a format which is directly
related to the highly acclaimed DH-101 preamplifier. Its
unique self-protecting output

stage

prevents the thermal

runaway

which is a common threat to solid

state

amplifiers.

The

ruggedness and conservative operation of the output

stage

allows the DH-200 to avoid the need for special protec-

tive circuits which could compromise audio performance.

Basic

protective

systems

provide maximum security against

malfunction

damage to the amplifier or the speaker: the AC

line fuse, B+

fuses,

thermal breakers,

and

loudspeaker

fuses.

Nothing

hinders the essential purity of the audio signal.

Those who use

these

instructions to

assemble

the

DH-200

kit will

find

that the

left

and right audio modules

(printed

circuit and

heat

sink

assemblies)

are preassembled

and

pretested.

This

greatly simplifies the kit assembly so that
it can be done in only a few hours without special skills or
know-how. Because of the modular arrangement, it is possi-
ble to operate on one channel if the other requires service,
and

obviates the need to return the entire amplifier in

cases

where one channel is inoperative.

Accessories for special applications include the input

bridging

circuit board for monophonic use; a panel for stan-

dard

19"

rack

mounting; and an alternative power

transformer

for international AC line

voltages.

Through

advanced engineering geared to the audio per-

fectionist, and an efficient no-frills approach,

Hafler

is mak-

ing

high technology high fidelity affordable.

CONTENTS

Operation

Page

3 AC

Line

Connections

for

Overseas

Use 12

Assembly

Instructions

4 Kit

Parts

List

13

Wiring

the Kit 6

Schematic

Diagram

14

If

Problems

Arise

10

Component

Value

Listing

15

Service

and

Warranty

11

Pictorial

Diagram

Insert

©

Copyright

1980.

All

rights

reserved.

2

INSTALLATION

The

DH-200 is most likely to be ihstalled out of sight in
most applications, since its power may be controlled by the
AC

switching of most audio preamplifiers, like the

Hafler

DH-101.

If your control unit

does

not provide switching

capacity sufficient for the amplifier's 5 amp

needs

(plus other

equipment it is

also

switching), you should use the amplifier's

own power switch. In that

case,

turn

on the preamplifier first;

then

turn

the amplifier on a few

seconds

after

the preamp has
been turned on, to avoid any unnecessary turn-on transients
from

some

preamplifiers. Likewise, switch the power

amplifier

off first.

If

the amplifier is to be installed

close

to a record player,

you

should first check its position for freedom from hum

pickup

by the cartridge from the field radiated by the power

transformer

of the DH-200. Although the design of the

transformer

minimizes such radiation, certain cartridges are

more

sensitive

than others, and require separation from the

amplifier.

Check

at a comparatively high volume setting, and

while swinging the

tone

arm throughout its arc. Often a few

inches additional spacing will eliminate the problem.

Be

sure to provide sufficient

ventilation

for the amplifier.

Unobstructed

air

circulation

around the finned

heat

sinks

and

above

the amplifier is important for long, trouble-free
life. Never put anything on top of the cover perforations. It is
normal

for the top and the

heat

sinks to become warm in use.

It is expected that the amplifier will always be resting on

its

feet,

which should be on a

hard

enough surface that air
flow underneath is not obstructed. If it is mounted in a rack,
or

through a panel, the

feet

may be removed so long as ade-

quate ventilation is provided through the bottom openings.

OPERATION

The

red pilot lamp which is integral with the power

switch

glows

whenever the amplifier is turned on. A blown

AC

line

fuse

is the most likely

cause

if it is not illuminated

when the amplifier is switched on.

The

yellow

lens

is a high temperature indicator. While it
is not likely that you will ever see it lighted, if it is, the
amplifier

will not produce sound. It indicates that one of the

thermal

breakers has shut down the amplifier

because

of ex-

cessive

temperature rise in a

heat

sink.

When

the

heat

has dis-
sipated in a few minutes, the amplifier should return to nor-
mal

operation. If the lamp again lights, check for insufficient

ventilation, or an

excessive

input signal, or an input which
may have dangerous signal content (such as oscillation).
Failing

evidence of this, the amplifier may have malfunc-

tioned. 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-200 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

to blow, a 2

amp

fuse

will protect most speaker

systems,

and only blow

when overload occurs. Smaller

fuses

tend to blow too easily,

and

larger

fuses

do not adequately protect most speaker

systems.

A

pair

of 5 amp

fuses

are

also

supplied as alternatives for

the speaker

fuse

holders. These should be substituted if the

power output of the amplifier is to be

tested,

or if the

amplifier

is to be operated at very high power

levels

into 4

ohm

loads.

If

the manufacturer of your speakers recommends a

specific value of

fuse

for their protection, we

suggest

that you

obtain 3AG

fuses

of that value and substitute them for the

ones

supplied.

Loudspeaker

Power Ratings

There

are no U.S. standards for rating the power han-

dling

capabilities of loudspeakers. As a result the manufac-

turers'

usual "music power" ratings, or

suggested

amplifier

limits,

are of only

minimal

help in determining

safe

operating

levels

with amplifiers which can deliver substantial amounts

of

power. You must take into consideration the type of

music, and the

levels

you like, to provide long term trouble-

free operation of

your

speaker choice, when you have a

size-

able amplifier like the DH-200.

Connections

AC

The AC

power cord should be plugged into 120 volts, 60

Hz,

on the switched output of a preamplifier which can

pro-

vide at

least

5 amps, or 600

watts.

Then

the amplifier power

switch may be

left

on, and it will be controlled by the rest of

the system.

Or,

it may be plugged into a 120 volt wall outlet,

and

switched on and off independently.

If

your line voltage is different, be sure you have the

alternate power transformer which can accommodate several

line

voltages,

and be sure it is

wired

for

your

mains voltage as

described later in this manual

before

you

plug

in the

amplifier.

Input

Conventional

shielded cables, such as

those

supplied
with your preamplifier, provide the input signal to the
sockets

on the back panel of the DH-200. Be sure that the
outer shield connection is secure, to avoid hum. The length
of

these

cables (so as to permit remote location of the

amplifier,

if desired) is limited only by the output impedance

of

the preamplifier. If it is 1,000 ohms or

less,

as with the

DH-101,

for instance, cable

lengths

up to 100

feet

are per-

missible without

loss

of performance. Special low .maci-

3

tance cables enable

even

greater distance

between

preanip

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 should avoid running

them parallel to

AC

cords —

these

should be crossed at right

angles.

Output

The

loudspeakers (or headphones) connect to the red

and

black terminals in the center of the back panel. These

binding

posts

provide several convenient alternative con-
necting methods. The screw cap may clamp the bared wire
end,

or a "spade lug" attached to it, but a better connection

will

be made by locating the hole

drilled

through the shaft of

the terminal when the cap is unscrewed. Insert the twisted

end of the bared wire so that the cap will clamp it in place.

Always

be sure that no strands of wire are unsecured, and

that the bared end is not too long to

risk

contacting other

ele-

ments. A soldered end or fitting is the

safest

solution.

These terminals

also

accept standard plug-in "banana pin

connectors," including the double

ones

with standard 3/4"

spacing, available from electronic supply

houses.

These are
the most convenient, especially if you may wish to in-
terchange speakers occasionally.

It is important to maintain correct phasing of the
speakers when making their connections. Some speaker ter-
minals are coded red and black, or + and —, etc. It is im-
portant that the

"sense"

of one speaker's connections match

the others. If one is reversed, you will

find

that the sonic im-
age has a "hole in the middle," and that it is deficient in bass.
Speaker wire always identifies one conductor to make this
easy.

There may be a molded ridge in one lead, or the color

of

the insulation on one wire is different, or the wire itself

may be color coded. If pin plugs are used, be sure they are

There

are three basic rules for

success

in electronic kit

building:

1. Read the instructions carefully, and follow them in
order.

2.

Make

secure solder connections which are bright and

smooth.

3.

Check

your work carefully after each

step.

The

DH-200 preamplifier is a versatile component with

sophisticated

circuitry

which has been made

remarkably

easy

to

build

by individuals with many years of experience in the
design and engineering of the finest performing audio kits,
and

in the preparation of their manuals.

Kit

building should be fun, and we are certain you will

find

this to be so. Assembly will be faster, easier, and more

enjoyable if

you

have

someone

help you by reading the

steps

aloud,

selecting the required parts, and

preparing

the

neces-

sary wire

lengths

in advance as you proceed. Fatigue in-

creases

the

risk

of

error,

so take a break rather than push to

early

completion. There are relatively few separate compo-

nents

in this design, to make it

easy

to pack everything away,

if

need be.

color

coded, or that you follow the indexing

mark

on one

side

of the double connectors.

Select

speaker wire of sufficient

size

to preserve the high

damping

factor (and

excellent

speaker control) of your

amplifier.

Standard 18

gauge

lamp cord ("zipcord") is

satisfactory for

distances

up to 30

feet

for an 8 ohm speaker.

As

the distance increases, larger wire

sizes

are recom-

mended. The

next

larger wire

size

is #16, and it is often

preferred

by perfectionists. If you have 4 ohm speakers, the

maximum

cable length for

best

results is halved.

The

black output terminals are electrically connected to

the

chassis

internally. Be certain that when the amplifier is

operated in its normal

stereo

mode that the red output ter-

minals are

never

connected together. In the special

case

when
the amplifier has been internally modified for monophonic
bridged

operation, the output is taken from the two red ter-

minals

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 phones, and thus minimize the likelihood of

hearing

component noise,

because

of the low setting re-

quired

at the volume control. Some headphone

boxes

utilize

a "common

ground"

system

which makes it

particularly

im-
portant that you carefully observe the proper connections.
While

the black ground terminals

can

be connected together,

the red

ones

must not be.

Some headphones, such as electrostatic types, are

less

sensitive

and may need little or no resistance in

series

for

normal

operation. These could be easily interchanged with

the speakers through the use of double banana plugs.

Your

work area should have good lighting, the proper

toots,

and a place where the large pictorial diagram can be

tacked to the wall within

easy

reach for checking. The

tools

should include:

1. A 40 to 100

watt

soldering

iron

with a 1/4" or smaller

tip which reaches at

least

600°F.

2.

60/40

(60% tin)

ROSIN

CORE

solder, 1/16" diameter

or

smaller.

3. A damp

sponge

or cloth to wipe the hot tip of the

iron.

4. A wire stripping tool for removing insulation.

This

can

be a

single-edge

razor blade, but inexpensive stripping

tools

are safer, faster and easier.

5. A medium-blade screwdriver (about 1/4" wide).

6.

Needle-nose

pliers (a long, narrow tip).

7. Diagonal or side-cutting small pliers.

8.

Large

"gas" or "slip-joint" pliers.

9. A 1/4" "Spin-tite" nut driver may be helpful, but is not

necessary.

4

ASSEMBLY

INSTRUCTIONS

A

soldering "gun" is not recommended. The unfamiliar
user is more likely to damage the etched circuit boards with
its higher

heat

potential and unbalanced weight.

Also,

because

he may not wait long enough for it to reach operat-

ing

temperature each time it is switched on, poor solder con-
nections are more likely. Pencil irons are much lighter and
easier to use, and there is no waiting time when solder con-
nections follow in

sequence,

as in kit building.

Make

sure

you

have a holder for it, though, and always unplug it when

you

take a break.

Proper

Soldering

There

are four

steps

to making a good solder connection:

1.

Make

a good mechanical connection to hold the wire in

position while

heat

and solder is applied.

2. Heat

the junction

of the wire and iug, or

eyelet,

with the

bright,

shiny tip of the

iron.

3.

After

heating for a couple

seconds,

apply solder to the

junction.

It should melt immediately and flow smoothly

around

both surfaces.

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. Eyelet connec-

tions, of course, are handled this way.

Good

solder connections are

essential

for trouble-free,

noise-free operation. A good solder joint

does

not require

much

solder

around

the conductors. Never

"butter"

partially

melted solder on

the

joint,

as it is

useless.

A good connection

looks smooth and bright

because

the solder

flows

into every

crevice when the parts are hot enough. The

iron

must have a

bright,

shiny tip to transfer

heat

easily to the

junction.

That's

why the damp

sponge

should be used frequently to wipe the

tip,

and occasionally you must add a small amount of solder

to the tip, too. If a connection is difficult to heat, "wet" the

tip with a small blob of solder to provide a bigger contact
surface to the joint. Once the solder

flows

around the con-

ductors,

any movement must be avoided for a few

seconds

to

allow a good

bond.

When

cool, check the connection by wig-

gling

the wire. If

ir.

doubt, or if the connection is not shiny,

re-heat the

joint.

Excess solder may be removed

from

a con-

nection 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. If

in

doubt

about

unmarked

solder, always obtain a fresh supply of

rosin

core solder. We recommend

60/40

for

easiest

use. Do not

confuse it with

40/60,

which is harder to melt.

The

general procedure is to use a hot

iron

for a short time

to

heat

a connection, then add solder with the

iron

still in

contact. Remove the solder

once

it flows, and then remove

the

iron.

A cooler

iron

applied for a longer time is more

likely

to damage components, or lift the copper circuit pat-

tern

from

the boards. A break in the etched circuit can be
mended by simply soldering a small piece of wire across it.
Do

not allow much build-up of solder on the tip of the

iron,

or

it may

fall

into adjacent

circuitry.

When

soldering to an

eyelet

on the

board,

insert the wire

from

the components side, and apply the

iron

to the bottom,

leaving

some

bare wire exposed so that you can see that the

eyelet

is then filled with solder for a secure bond. A

round

wooden toothpick is

suggested

so that you can

heat

and clear

an

eyelet

of solder if it hinders your inserting the wire. Some

builders

prefer to clear every

eyelet

first with a touch of the

iron

and toothpick.

Others

connect the lead by

bringing

it up

to the center of the

eyelet

on top of the

board,

applying the

iron

from

the bottom of

the

board,

and

pushing the lead in as

the solder in the

eyelet

melts. If the wire has first been

"tin-

ned,"

usually no additional solder is necessary, but it is a

good practice to push the wire

through,

and then back it up a

bit,

to be sure solder fills the

eyelet

from

both

sides.

On the

bottom of the

board,

make certain a

bright,

shiny flow is evi-

dent

from

the wire, across the

eyelet,

onto the circuit pattern

on

the

board.

It is

essential

that the

eyelet

be fully soldered to

the

.circuitry,

too.

"Tinning"

refers to the process of

applying a light coating

of

solder to the bared wire end.

This

keeps

all the strands

secured, and

also

makes a good connection easier. Simply

touch the wire with the

iron

for a couple

seconds,

and apply

solder.

Allow

the

excess

to flow away onto the

iron.

When

properly

done, the wire is uniformly bright, and no larger

than

before. The hookup wire supplied with this kit

does

not

normally

need tinning, for it is pre-tinned.

5

Wiring

the Kit

Mechanical

Assembly

If

any components are unfamiliar to you, checking the

pictorial

diagram

should

quickly

identify them.

Or,

the

quan-
tities, and the process of elimination as you check the parts
list,

will

help. The pictorial diagram is necessarily distorted

to

some

extent

for

clarity,

so that you can trace every wire in

a

single overall view for verification as you work. You may

wish to check off

on

the

diagram

as you solder each location.

To

"prepare"

a wire means to cut the designated length

from

the coil of that color, and strip about 1/4" of insulation

from

each end. The wire supplied in the kit is #18, so you

can

set adjustable wire-strippers accordingly. The

transformer

leads are #16 or 18, and the line

cord

is #18.

Be

careful that you do not nick the wire when you strip it

(that

can

happen more easily

if

you

do not use wire strippers)

for

that

weakens

it. The wire supplied in this kit is "bonded

stranded,"

which provides exceptional flexibility with resis-

tance to breakage for easier use.

Whenever

a connection is to be soldered, the instructions

will

so

state,

or indicate by the symbol (S). If

more

than one

wire is to be soldered to the same point, they

will

be

indi-

cated by (S-2), (S-4), etc. If soldering is not called for, other

connections have yet to be made to that terminal.

They

would

be more difficult if the connection was already

soldered.

Every

connection in the kit

will

be soldered when

it is complete.

After

soldering a connection, it is

best

to clip

off

any

excess

lead length to minimize the possibility of a
short circuit (as on switch lugs, where terminals are very
close

together), and for

neatness.

Be

sure that uninsulated wires cannot touch adjacent ter-

minals or the

chassis

metalwork.

The

symbol (#) indicates a connection is to be made to

that point.

When

a lug number is specified without (#), it is

simply

a locating reference.

When

the instructions

call

for twisting two or three wires

together, the length of wire indicated anticipates a

fairly

tight,

uniform

twist

by

hand,

of three

full

turns every two in-

ches. If

you

find

the wires too short, loosening the

twist

will

gain

some

needed length.

Handle

the

circuit

boards

carefully.

They

represent a ma-

jor

part

of the kit

cost.

Stand-up

components, such as transis-
tors, should be checked when you install the module, to be
sure all leads are separated.

All

of

the

active

circuitry

is contained on the

PC-6

board,

which

has been carefully

tested

to assure that it

meets

every

specification.

Only

the interconnection of power supply

ele-

ments 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

continue to

perform

properly

for years to come.

Check

your

work,

and make sure the entire

step

has been completed

before placing a check

mark

in the space

provided,

and con-

tinuing

on to the next

step.

KEP

nuts have been supplied as a convenience. These

have lockwashers attached, and the lockwasher always

goes

onto the screw first. If the

sheet

metal

screws

have hex heads,

you

may

find

it easier to first start them with a regular

screwdriver,

to set the thread, and then use the more con-

venient nut

driver,

if one is available.

1 •

When

you unpack your kit, you

will

find

that the

transformer,

large capacitors, and the output assem-

blies have been temporarily fastened to the

chassis

for

safe

shipment. Disengage

these,

and include this

hard-
ware with the rest when you check off the components
against the parts list in the back of the manual. We
recommend

this check-off to be sure you have every-

thing,

and to enable you to identify any unfamiliar
items by comparing them with the pictorial diagram.
An

egg

carton

is ideal for keeping

hardware

items sepa-

rated.

A

"set" of hardware includes one screw and one

KEP

nut
(with its attached lockwasher). Always install the lockwasher
side of the nut first. If the

size

of the hardware is not

specified, use the #6 size. The smallest

size

is #4 and #10

the largest. Always insert the screw

from

the outside of the

chassis.

It

will

simplify matters if

you

first separate the #4 nuts

from
the #6 nuts, which have the same outside dimensions. A #4
screw

will

pass

through a #6 nut, aiding identification.

2 • Select the four rubber

feet,

four

sets

of

hardware,

and
the chassis. Insert each screw through a foot so that the
head is recessed, and install the

feet

on the outside at

each corner hole.

3 • Select the two red output terminals. Install them in the

sequence

shown below, in the two center

holes

R2 and

R3

at the rear of the chassis. Before you fully tighten

the first nut, unscrew the cap to

expose

the hole

drilled

through

the threaded shaft. Connection of loudspeaker

wires

will

be easier if

these

holes

are positioned ver-

tically. A nail

through the hole

will

keep it positioned

while the hardware is tightened.

Each

connecting lug

should

point downward before the last nut is secured.

Be

sure both nuts on each terminal are tight, as they

are difficult to reach when the amplifier is completed.

4 • Select the two black output terminals and install them

on

either side of

the

red

ones,

at Bl and B4. Be sure the

shaft

holes

are vertical, the lugs point downward, and

each nut is tight.

5 • Select the two

round

fuse

holders, and two each 1/2"

rubber

washers, lockwashers and nuts.

First

install the

rubber

washer on the holder, so it

will

be outside the

chassis, and then fasten the

fuse

holders at

LF

and

RF,

with the tip lugs

pointing

away

from

each other, toward

the

edge

of the chassis.

6

6 • Select the larger

round

input socket, its insulating disc,
the solder lug with lockwasher teeth, two #4 screws,
and

the two nylon nuts.

This

socket

will

be installed at

RS.

The inside of

the

chassis

at

RS

and

LS

has not been

painted,

so that a good ground connection can be

made. It may be necessary to clean this with a solvent,

or

with an eraser, before the

sockets

are installed. Place
the solder lug on the lower mounting screw inside the
chassis, followed by the insulating disc, then the socket.
Position

the lug toward the

edge

of the chassis. The

shorter

ground

lug on the socket should also be nearest

this right

edge.

Secure this socket with the nylon nuts.

7 • Select the other input socket and two

sets

of #4

hard-

ware. Install it at

LS

after cleaning the unpainted area,

with its short ground lug near the left

edge

of the

chassis.

8 • Select the four-lug rectifier block RB, the long #6

screw, and a nut. Install the rectifier in the center hole
near the rear of the chassis, with the plus (+) terminal
located over the tiny indexing hole at position four.
Correct

orientation of this rectifier is essential for

proper

wiring.

9 • Select the single

fuse

clip,

and one set of #4 hardware.

Install the clip in the right front

chassis

hole

FC,

closest

to the foot.

10 • Select the two

dual

fuse

clips and four

sets

of #4

hard-

ware. Install

these

in the pairs of

holes

FL

and FR on

either side of the center of the chassis.

11 • Select the two-lug terminal strip and one set of #4

hardware.

Install it in the front hole TS, next to the

single

fuse

clip.

Note the position of the mounting lug

(to the right) in the pictorial diagram.

NOTE:

Kits

provided

with

the

multiple

voltage

power

transformer

for

locations

outside

;K-

United

States

which

use a

line

(mains)

voltage

other

than

120

VAC,

are

also

supplied

with a five-lug

ter-

minal

strip

which

is

to be

installed

in

place

of

the

two-lug

strip,

using

an

additional

set

of

#4

hardware

near

the

dual

fuse

clip.

12 • Select the power switch. If

it

says

"Carting,"

position it

with

lug

#3 at the top. If

it

says

"Chicago,"

position the

small

protruding

plastic lug at the bottom. Snap it fully

into the front

chassis

hole PS

from

the outside.

A

soldering

iron

will

be used

regularly

for installing the wir-

ing.

Be sure you wipe its tip frequently with a damp cloth or

sponge, as a bright tip

will

make connections easier with

less

likelihood

of overheating components. If it is difficult to heat

a

connection in a couple of seconds, apply a small

amount of

fresh

solder to the tip so it can flow around the connection

and

provide good heat transfer.

Take

the time to observe the direction each wire

takes

from

its connecting lug, so that when you connect the first end, it

will

be pointing in the right direction.

This

makes the job

neater, and assures that each wire is long enough.

13 • Prepare a

6-1/2"

green wire. Connect one end to

dual

fuse

clip

FL

lug #

1.

Connect the other end to the other

dual

clip FR lug #1. (S).

14 • Prepare a

6-1/2"

white wire. Connect one end to FR

lug

#3. Connect the other end to

FL

lug #3. (S).

15 • Select the 2.2 ohm (red-red-gold) resistor. Cut each

lead

to 112" or

less.

Connect one end to the separate

solder lug installed under input socket RS. (S).

Con-
nect the other end to the short (ground) lug #2 of
socket RS.

16 • Prepare a 10" green wire and a 10" white wire. Twist

these

together uniformly (about three complete

twists

every two inches). Connect the green wire to the short

RS

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

#

1.

(S). Place

these

wires out of

the

way, over the

edge

of

the chassis.

17 • Select one of the

.0047

mfd

film

capacitors. Cut each

lead

to 1/2", and connect one lead to

fuse

holder RF

lug # 1.

Connect the other lead to RF lug #2.

18 •

Prepare

two 8" white wires.

Start

with

one wire project-

ing

3/4" beyond the other, and

twist

them uniformly
together throughout their length. Connect the project-
ing

end to RF lug #1. (S-2). Connect the correspond-

ing

end of

the

other wire to

RF

lug #2. (S-2). Place this

pair

over the

edge

of the chassis.

19 •

Prepare

an 11" white wire

and a 9"

green wire. Starting
with the white wire 3/4" longer than the green wire,
twist

them together to within one inch of the other end

of

the green wire. At the beginning end, connect the
green wire to output terminal lug #B4. Connect the
white wire to lug #R3. (S). Place

these

wires off to the

right.

20 • Prepare a 6" green wire. Connect one end to lug #B4.

(S-2).

21 • Prepare a 10" white wire and a 10" green wire. Twist

them together, and connect the green wire to the short
LS

lug #1. (S). Connect the white wire to LS lug #2.

(S). Place

these

wires to the left, over the

edge

of the

chassis.

22 • Select the remaining

.0047

mfd

film

capacitor, and cut

each lead to 112". Connect one lead to

LF

lug #

1,

and

the other lead to

LF

lug #2.

23 • Prepare two

7-1/2"

white wires. Start with one wire

3/4" longer, and

twist

them together throughout their

length. Connect the longer end to LF lug #2. (S-2).

Connect

the other wire to

LF

lug # 1.

(S-2). Place

these

wires off to the left.

24 • Prepare a

9-1/2"

white wire and a 10" green wire.

Starting

with the white wire 3/4" longer than the green

wire,

twist

them together to

within

one inch of

the

other

end

of the white wire. At the beginning end, connect

the green wire to output

terminal

lug

#B1.

Connect

the

white wire to lug #R2. (S). Place

these

wires off to the

left.

25 • Prepare a 6" green wire. Connect one end to lug #B1.

(S-2).

7

26

• Prepare two 20" white wires, and

twist

them

together
throughout their length. Six inches in from one end of
the

pair,

cut one of the wires, and unwind it about

1-1'2"

in each direction from the cut. Strip 1 4" of

in-

sulation from each of

these

cut ends. Place the longer

portion

of the wire along the lower front

edge

of the

chassis, with the break at the single

fuse

clip. Connect

one cut end to

TS

lug #2. Connect the other cut end to

power switch lower lug #

1.

The unbroken w ire

of this

pair

may be placed under the power switch for neat-

ness,

and the free

ends

project from the front corners of

the chassis.

27 • Select

the power transformer, four

sets

of 1'2" long
#10 hardware, and the four flat washers. Position the
transformer

so that the red

leads

emerge near the

center of the chassis. The black and black/white

leads

(and all of the brown

leads

as well, if it is the multiple

voltage version) should project toward the power

switch. Be sure no wires are pinched in the installation.
Place the white twisted

pair

under the front

chassis

lip.
Install a flat washer on each screw through a
transformer

foot before the nut is secured.

The

transformer

leads

can be trimmed as desired for a

neat

job,

but be sure you do not cut any of

thern

too short (panic

ularly

if the multiple voltage version is used, and any change

in

the supply voltage is likely).

Cutting

the

leads

too short for
re-use may void the transformer warranty, if it is thought to
be defective. Alternate wiring diagrams tor the optional

multiple voltage version will be found

elsewhere

in this

manual.

If you have that transformer, consult them before

wiring

the transformer and power switch.

Be

sure all strands of each transformer lead are tinned and

soldered

together

before connection to a lug, so that there is

no

possibility of a stray strand touching anything but the in-

tended lug.

28

• Connect the black transformer lead to PC lug #2.

29

• Prepare a 2" green wire. Connect one end to FC lug

#2.

(S-2).

Connect the other end to

PS

top lug #3. (S).

30 • Connect the black/white transformer lead to TS lug

#2.

31 • Select

the yellow lamp assembly and the spring

steel

nut.

Trim

the lamp

leads

to 2", and install it from the

outside at

HT.

The center of the nut curves away from

the

chassis

when it is pressed over the lamp

case.

Be

sure it is pressed fully home, so the lamp is tight.

32 D Connect one lead

of

the lamp to

TS

lug #2.

(S-3).

Con-

nect

the other lamp lead to PS lower lug #1.

33 •

Select

the .005 mfd disc capacitor, and

trim

its

leads

to

1/2" or

less.

Connect one lead to PS lug #1.

(S-3).

Connect

the other lead to PS lug #2

34 •

Select

the AC line cord and the plastic strain relief.

Separate the two conductors for

2-1/2".

Cut

1-1/2"

off

of

one of the two leads, and strip 1/4" of insulation

from

each lead. Twist the strands tightly, and tin each

end.

Nine-and-a-half inches from the

longest

end,

make a sharp "V" in the cord by bending it back
sharply

on

itself.

Install the strain relief as shown, with
the small end of the strain relief nearest the stripped
end of the line

cord.

Crimp

the two halves of the strain

relief

around

the wire at the

"V"

with heavy pliers, to

partially

form it before insertion into the back panel.

Then

grip the larger diameter of the strain relief with

the tips of the pliers,

squeeze

it tightly, and insert the

end of the cord and the strain relief through the back

panel

hole

AC,

from the outside. Note that the hole has

a flat on one side, and the strain relief is installed ac-

cordingly.

It snaps into position when fully inserted.

Place the line cord under the other wires.

35 • Connect the longer end of the line cord to PS lug #2.

(S-2).

Connect the shorter lead to

FC

lug #1. (S).

36 •

Select

the two red transformer leads. Connect one lead

to RB lug #2. Connect the other lead to RB lug #3.

37 •

Select

the .01 mfd disc capacitor, and

trim

its

leads

to

3/4".

Strip

two 1/2"

pieces

of insulation from the white

wire,

and slide one piece over each of the disc capaci-

tor

leads. Connect one lead to RB lug #2.

(S-2).

Con-

nect

the other lead to RB lug #3.

(S-2).

38 • Prepare a 6" white wire. Connect one end to RB lug

#4. (S). Be sure this is the (+) terminal of the rectifier.

39 •

Select

one of the round capacitor brackets, two

sets

of

#6 hardware, one of the 3/4" #10

screws

and its nut,

two short #10

SEMS

screws

(with lockwasher at-
tached), two solder lugs, and one of the large capaci-
tors. Insert the short

screws

through the solder lugs,

and

install them loosely in the capacitor terminals. In-
stall the long screw in the bracket clamp, noting the
direction

of insertion in the pictorial diagram (to

pro-

vide

easy

future

access),

and tighten that nut about half

way. Place the assembly in position on the chassis, on

8

the right side, nearest the power switch. Install the two
sets

of hardware to secure the bracket to the chassis. If

the bracket

twists

as the

screws

are tightened, first in-

stall the capacitor, and clamp it.

Make

sure the capaci-

tor

is tight against the chassis, and that its positive ( + )

terminal

is toward the

right

side

of the

chassis

before

tightening the clamp. Position the lug on the ( + ) ter-

minal

(it will be painted red if it is not marked with a

+ ) so it points forward toward the power switch, and

tighten its screw. Point the

negative

terminal lug

toward

the rectifier block to the left, and tighten that

screw.

Make

sure no wires are trapped by the bracket.

40 •

Select

the remaining capacitor, its bracket, two

sets

of

hardware,

the long #10 hardware, the two short #10

screws, and the two solder lugs. Install this assembly as

in

the preceding

step,

but be sure the positive lug of the

capacitor is nearest the center, pointing toward the

other capacitor's

negative

lug. The

negative

lug of this

second capacitor points forward.

41 •

Select

the white wire from RB lug 4 (marked + ) and

connect it to CR lug #2.

42 • Prepare a

4-3/4"

white wire. Connect one end to FR

lug

#3.

(S-2).

Connect the other end to CR lug #2.

(S-2).

43 • Prepare a 6" green wire. Connect one end to RB lug

#1. (S). Connect the other end to

CL

lug #1.

44 • Prepare a

4-3/4"

green wire. Connect one end to FL

lug

#1.

(S-2).

Connect the other end to CL lug #1.

(S-2).

45 • Remove all of the insulation from a

2-3/4"

white wire.

Connect

one end to

CL

lug #2. (S). Connect the other

end to

CR

lug #1. (S).

46 • Connect the red/yellow transformer lead to the center

of

the bare wire

between

the capacitor lugs. (S).

47 • Connect the separate green wire from output terminal

Bl

to the center of the bare wire,

next

to the

transformer

lead. (S).

48 • Connect the separate green wire from B4 to the center

of

the bare wire also. (S).

49 •

Select

the output assembly modules (the two major

items

in the kit).

You

will

note

that the only difference,

which

identifies the

left

or the right module, is the posi-

tion of the thermal breaker, which is located

between

one

pair

of output transistors on the

heat

sink rib.

Before connecting wires to

these

modules it is

best

that

you

take the time to make absolutely certain that each

eyelet

is well soldered to the circuitry on the back (in-

side)

of the

board.

Add

a little solder if necessary, but it
is important that solder flow from the wire, across the
eyelet,

and onto the

circuitry.

Then

if

you

wish to clear

the center of the

eyelet

for easier insertion of the wire,
use a round wooden toothpick after heating each
eyelet.

Now position the right module (with the

breaker

at the front when the long row of

eyelets

is

next

to the

chassis)

with the circuit board up, against the

chassis.

Wires

will be connected from the top ot the

board,

and they

must be soldered to the underside.

Even

though the connect-

ing

wires will be rather long when the amplifier is completed,
they are just long enough to reach now, so working room is
limited.

It is

best

to

heat

the

eyelet

from below while the wire

is inserted from above.

That

requires

an

iron

with a small flat

chisel tip — and

some

care on your part. It is

easiest

to melt a

small

blob of solder on the tip, and position it under the

eyelet

so that the solder blob, more than the tip

itself,

is heat-

ing

the

eyelet.

If the

eyelet

is first filled with solder, and the

wire end pushed all the way through the heated

eyelet

first,

then withdrawn part way to

expose

a bit of the bare end

above the board before the solder cools, you should have a

firmly

soldered connection if it

cools

undisturbed.

Always

tin a wire that is to connect to an

eyelet.

After

solder-

ing,

go back and check by twisting each wire, to make sure

nothing

moves

on the other

side

of the

board.

Be careful, too,
that you don't loosen existing connections .to adjacent
eyelets.

For a bit better

access

to

these

connections, you may

wish to remove the three mounting

screws

to allow the circuit

board

to be moved, but don't forget the nylon washers under

the

board.

50 •

Select

one of the narrow numbered strips, and peel off

the backing.

This

identifies the

eyelet

numbers, and

should be placed along the bottom of the circuit

board,

with

eyelet

#14 nearest the power switch.

51 • Prepare a 6" white wire. Connect one end to

eyelet

#4

of

the circuit

board.

(S).

52 • Prepare a

5-112"

green wire. Connect one end to

eyelet

#13. (S).

Make

sure it cannot contact the transistor

mounting screw near the underside.

53 •

Select

the green and white twisted

pair

from

the output
terminals R3 and B4. Connect the shorter green wire to
eyelet

#6. (S).

54 •

Select

the

pair

of white wires from RF. Connect the

shorter wire to

eyelet

#8. (S). Connect the other wire

to

eyelet

#11. (S).

55 • Connect the remaining white wire from the green and

white

pair

from the output terminals to

eyelet

#12. (S).

56 • Connect the green wire from

eyelet

13 to FR lug #2.

(S).

57 • Connect the white wire from

eyelet

4 to

FR

lug

#4. (S).

58 •

Select

four of the long

sheet

metal screws.

Take

care to
see that no wires are pinched in the process, while you
tilt up and fasten the module to the end of the chassis.

59 •

Select

the green and white

pair

from input

socket

RS.

Connect

the white wire to the top rear

eyelet

# 1. (S).

Connect

the green wire to

eyelet

#2. (S).

This

pair

will

be specifically positioned later.

60 •

Select

the white

pair

at the front.

Tuck

the

excess

wire

into the corner of the chassis, and connect one lead to

each of the

lugs

on the thermal breaker. Solder each.

9

61 •

Select

the

left

output module, make sure all its

eyelets

are well soldered, and place it against the

left

side

of

the chassis, board up, breaker at the front.

62 •

Select

the

remaining

strip of

eyelet

numbers,

and

install

it with

eyelet

#3 at the front.

63 • Prepare a 6-1/2"

green wire. Connect one end to

eyelet

#13. (S). Be sure it cannot touch the transistor screw.

64 • Prepare a

5-1/2"

white wire. Connect one end to

eyelet

#4. (S).

65 •

Select

the green and white

pair

from output terminals

Bl

and R2. Connect the shorter white wire to

eyelet

#12. (S)

66 •

Select

the white

pair

from

LF.

Connect one wire to

eyelet

#11. (S). Connect the other wire to

eyelet

#8.

(S).

67 • Connect the remaining green wire from the output ter-

minal

pair

to

eyelet

#6. (S).

68 • Connect the white wire

from

eyelet

4 to

FL

lug #4. (S).

69 • Connect the green wire from

eyelet

13 to

FL

lug #2.

(S).

70 •

Select

four

sheet

metal

screws

and fasten the module to

the chassis, making sure no wires are pinched.

71 •

Select

the green and white

pair

from input

socket

LS.

Connect

the green wire to rear

eyelet

#2. (S). Connect

the white wire to

eyelet # 1.

(S).

72 •

Tuck

the

excess

of the remaining white

pair

of wires

into the

left

front corner

of

the chassis,

and

connect one

wire to each lug of the thermal breaker. Solder each.

73 •

Select

the 5 amp slo-blo

fuse

(a slo-blo

fuse

has distinc-

tive internal construction) and install it in the single

fuse

clip

FC.

74 •

Select

four 5 amp regular

fuses,

and install them in the

dual

fuse

clips

FL

and FR.

75 •

Select

the two 2

amp

fuses,

and install them in the

twist

type

fuse

holders on the back panel. These

fuses

will

provide

reasonable protection for most speakers. See

the

Operation

section of this manual for more detailed

information.

The remaining 5 amp

fuses

are alternates

for

the back panel holders for high power

test

pur-

poses.

76 • For

lowest

distortion performance, precise placement

of

some

wires is important. The wires from the output

terminals and the back panel

fuse

holders should be
kept against the chassis. They should be positioned
over to the input

socket,

and then straight forward to

the

board.

The input

socket

pairs

should be

close

to the

chassis, but above the other pairs, straight to the center

bottom of the circuit

board,

and then up the middle of
the board about 1/2" out, right in the plane defined by
the

edges

of

the

finned

heat

sinks.

The

wires to the dual

fuse

clips should be kept away from the board and

against the chassis, bringing the

excess

length forward

of

the

fuses.

The

leads

from the power supply capaci-

tors should be kept away from each

board.

The green

leads

from

the black output terminals to the power sup-

ply

should be brought

together

throughout most of

their length.

77 •

Check

all your soldered connections — especially

those

on the

fuse

clip lugs, which are

sometimes

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

connections. Now

turn

the amplifier upside down and

shake out any bits of wire or solder.

78 • Slide the cover in place, and install it with the

eight

sheet

metal screws.

79 • Remove the backing

from

the serial number label, and

apply

it to the bottom at the center rear.

CONGRATULATIONS!

YOU

HAVE COMPLETED ONE

OF

THE MOST

TECHNOLOGICALLY

ADVANCED

AND

SUPERB

SOUNDING

AMPLIFIERS EVER DESIGNED.

IF

PROBLEMS ARISE

A

great deal

of

care has

gone

into every

Hafler

amplifier,

whether kit or factory assembled, to be sure that it

meets

or

exceeds

all its specifications before it is shipped to you. Ev-

ery

assembled amplifier must

pass

a battery of performance

tests.

In the kit, each output module assembly was in-circuit

tested

to similar standards. Since

these

modules comprise all

of

the active amplifier

circuitry,

save

for the power supply, it

reduces the likelihood of an internal problem to near zero,

with careful assembly.

If you

are certain the problem

lies

in the power amplifier,
check first to see that the red pilot lamp is lighted. If it is on,
and

the yellow lamp is lighted, this indicates that the

thermal

safety

breaker on one channel has shut down the amplifier

because

of

excessive

temperature. In this

case,

the

heat

sink

will

be very hot to the touch.

After

a few minutes to cool, the

amplifier

will commence operation automatically. If it soon

shuts

down again,

and

the amplifier has sufficient ventilation,
the malfunction is either internal, or the result of an ex-
cessive

(and very likely inaudible) input signal.

If

neither lamp is lighted, the main

fuse

in the single

fuse

clip

on the

chassis

is probably open. If a replacement 5 am-

pere, Slo-Blo

fuse

also

blows, the amplifier

needs

service,

and

there is a power supply problem.

If a

problem

appears only in one channel

of

the amplifier,
it may be isolated from the rest of the amplifier by removing
the power supply

fuses

to that channel in the adjacent dual

fuse

clip. The other channel may then be operated

monophonicalfy. The

Hafler

company

does

not encourage

local

service of this amplifier. The one adjustment poten-
tiometer is sealed at the factory at the operating point for
lowest

distortion, and you should not readjust it. The ad-

10

vanced design of this circuit means that

some

components

will

not likely be available locally, and alternative replace-

ments

are not recommended at all.

We

recommend that a defective output module be sepa-

rated

from the amplifier, and returned for service at the fac-

tory.

This

reduces shipping

weight

and the likelihood of

damage, and

enables

you to operate the other half if you

wish. In this

case,

we

suggest

that the connecting wires be un-

soldered at the

eyelets;

that each wire be tagged with the

eyelet

number (visible inside the

board,

along the

edge

— or

see the board diagram in this manual); that the bare wire

ends

all be insulated; the dual power supply

fuses

for that

channel be removed; and the wires to that thermal breaker

on

the

heat

sink fin be disconnected and temporarily

soldered

together,

and insulated.

SERVICE

POLICY

AND

LIMITED

WARRANTY

The

DH-200 Power

Amplifier

has been carefully
engineered to provide many years of use without requiring
any maintenance or servicing.

Factory

assembled units are subjected to several physical

and

electrical

tests

before shipment.

The

output

circuit

board

assemblies

of kit units are similarly

tested

prior

to shipment.

In

spite

of all this testing, shipping damage

does

occur, kits

are not assembled properly or

someone

"goofs"

and service

and/or

maintenance will be required. The

David

Hafler

Co.
provides complete service facilities at the factory to make
any necessary repairs.

It is the owner's responsibility to

return

or

ship

the

unit

freight

prepaid

to

the

factory

service

department.

Units

ship-

ped

freight

collect will

not be

accepted.

For

units

to be

repaired

under

warranty a copy

of

the

dated

bill

of

sale

must

accompany

the

unit.

Shipment should be made via

UNITED

PARCEL

SER-

VICE.

Parcel Post is not a

safe

way to ship electronic equip-
ment. The factory will not be responsible for damage caused
by

parcel

post

shipment and repairs will be made at the

owner's

expense.

When shipping your DH-200 be sure to in-

sure it for the

full

value of an assembled amplifier.

Use the original carton and packing material to ship your

amplifier.

Enclose with the unit the following information:

1. Complete shipping address

(Post

Office Box numbers

are often not acceptable).

2. The serial number.

3.

Copy

of dated

bill

of

sale

if

repairs

are to be made under

warranty.

4. Description of the malfunction. If intermittent,

please

note.

5. We

also

suggest

further identifying the unit as yours by

putting a label on the bottom or tieing a label with your

name and address on the line

cord.

All

service work is guaranteed for 90 days.

Warranties

apply to the original purchaser only.

Warran-

ties

are void if:

1. The amplifier has been either physically or electrically
abused or used for

some

purpose for which it was not

designed.

2. The amplifier has been modified without factory
authorization.

The

transformer warranty is void if the

leads

have been

cut too short for reuse.

If you

think a transformer is defective

the

leads

must be unsoldered, not cut, for its return.

Technical

assistance

to help you locate the source of a

problem

may be obtained by writing the Technical Services

Department. 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 transistors), you may remove and return
only the module for service. Be sure that the components on
the circuit board are well protected — as by a surrounding
sleeve

of corrugated cardboard which

rests

against the

heat

sink,

and projects beyond the components. Properly packed
and

insured for $150, this assembly can be

sent

by parcel

post, as well as

UPS,

if necessary. A service fee of $20 must

be

sent

with

every

module, since the fault may have been

caused by a wiring

error

elsewhere.

For

this reason, too, and

because

we have no control over its

proper

reinstallation, the

service

warranty

on a separate module is limited to assurance

of

its proper functioning when it

leaves

the service facility.

All

modules are

tested

before return to you. If you believe

the fault is the factory's warranty responsibility, include the

serial

number and the

bill

of

sale.

If in our judgement the

fault is entirely a manufacturing

defect,

a portion of the ser-

vice fee will be refunded.

Only

a complete amplifier can be

completely checked and given a service warranty.

WARRANTY FOR KIT-BUILT

UNITS

The

parts in a DH-200 kit are warranted for a

full

year
from the purchase date. If a defective component is found on
a

circuit

board

or in a kit, simply

return

the

individual

part

to

the factory prepaid

together

with the serial number and the

date of purchase, and it will be replaced at no charge.

If

you cannot locate what is wrong with your DH-200,

return

it to the factory with a copy of the dated

bill

of

sale,

and

a check for $40. If the

sole

cause

of the

problem

is a de-
fective part, the unit will be repaired and returned to you
transportation

prepaid, and your $40

less a charge

for re-

packaging

and

shipping

will be

returned

to

you.

If the

prob-

lem is found to be an

error

in your assembly of the

ampli-

fier,

the amplifier will be put in proper working

order,

test-
ed to be sure it is meeting specifications, and returned to
you

(freight prepaid within the continental U.S.). Excess

shipping

charges for expedited service, or

overseas

delivery

are your responsibility. At the

sole

discretion of the factory
service department, if the time required for diagnosis,
repair

and testing, and the nature of the malfunction war-
rants it, a portion of the submitted repair fee may be
rebated.

This

warranty is void if the kit has not been completely
assembled or if other than rosin core solder has been used.
Units

assembled with acid core solder or

paste

flux will be

returned

unserviced.

WARRANTY FOR FACTORY ASSEMBLED

UNITS

The

DH-200 is warranted for a

full

year from the

purchase date including parts and labor and

normal

shipping

costs

from the factory to the owner within the continental

U.S.

The owner is responsible for returning the unit to the

factory and must submit a copy of the dated

bill

of

sale.

This

warranty

gives

you specific legal rights. You may

also

have other rights which vary from

state

to

state.

AC

LINE

CONNECTIONS

FOR

OVERSEAS

USE

The

power transformer supplied in DH-200 amplifiers

sold in the USA is intended for 120 volt, 60 Hz operation

only. For use in other countries, a multi-voltage transformer

is available at higher

cost.

It has dual tapped

primary

wind-

ings

which can be arranged in various series-parallel com-
binations for 100, 110, 120, 200, 220 and 240 volt 50 or 60
cycle lines. The schematic diagram

details

the wiring com-

binations which are represented pictorially here.

Note that a 5-lug terminal strip is required when the

multi-voltage transformer is used.

This,

and the

100,000

ohm

resistor which is

sometimes

needed to illuminate the
pilot lamp, is supplied in kits which include the special
transformer.

If the amplifier is operated with 200 to 240 volt

lines, the 5 amp line

fuse

which is supplied should be

replaced with a 2-1/2 amp Slo-Blo type

fuse.

12

KIT

PARTS

LIST

Minor

variations

may sometimes

be

encountered

in

value

or

appearance. These will

not

affect

performance.

13

Fuse

Envelope

Part

No.

6

Fuse, 5 ampere

341050

1

Fuse, 5 ampere, Slo-Blo

342050

2 Fuse, 2 ampere

341020

Hardware

Envelope

Part

No.

1

Lug,

solder type, internal tooth,

#6

619308

4

Lug,

solder type,

#10

629508

8

Nut,

#4-40

KEP

614245

9

Nut,

#6-32

KEP

614345

4

Nut,

#10-32

KEP

614565

2 Nut,

#10-32

KEP,

for

clamp

614569

1

Nut, spring

steel,

Tinnerman

type

610041

2 Nut,

#4-40

nylon

694241

2

Nut, 1/2", for fuse

holder

615074

10

Screw, machine,

#4 x

5/16" 611255

8

Screw, machine,

#6 x 1/2"

611385

4

Screw, machine,

#10 x 1/2"

611585

2 Screw, machine,

#10 x 3/4"

for

clamp

611579

4

Screw,

#10 x 1/4",

SEMS

611545

16

Screw,

sheet

metal,

#6 x 1/2"

612387

1

Screw, machine,

#6 x

3/4" 611375

4

Washer, flat

7/8" 616575

2 Washer, locking, internal tooth,

1

/2"

for fuse

holder

617085

2 Washer, rubber,

1/2" for

fuse

holder

696081

1

Chassis

711007

1

Cover

711008

2 Capacitor,

10,000

mfd,

75V 294103

2 Bracket, round,

for

capacitor

717058

1

Diode rectifier block

544252

4

Feet, rubber

899757

2 Fuse holder, round

351003

1

Fuse clip,

single

351002

2 Fuse clip, dual

352001

1

Indicator light assembly

526001

1

Input

socket,

round

351318

1

Input

socket,

narrow

351326

1

Insulator disk, round,

for

socket

815318

1

Label,

serial number

808005

1

Line

cord,

with plug

322001

2 Output module assembly

(1

each,

left

and right)

994001

2 Output terminal, black, with hardware

351005

2 Output terminal, red, with hardware

351006

1

Power switch

332001

1

Strain relief, plastic

895001

1

Terminal

strip, 2 lug 373181

alternate 5 lug

for

international

use

377181

1

Transformer, power

464002

alternate

for

international

use 464003

1

Wire,

white,

#18

1

Wire,

green,

#18

1

Registration card

Small

Parts

Envelope

part

No.

1

Capacitor,

.01

mfd, disc

238103

1

Capacitor,

.005

mfd (5000M), disc

238502

2 Capacitor,

0047

mfd film

264472

1

Resistor,

2.2

ohms

133022

2 Numbered strip,

for eyelets 808101

SCHEMATIC
DIAGRAM

©

Copyright 1980.

All

rights reserved.

COMPONENT

VALUES

Part

No.

Rl

470,000

ohms

139474

R2

2,200

ohms

139222

R3

22,000

ohms

139223

R4

100

ohms

139101

R5

100

ohms

139101

R6

2,200

ohms

139222

R7

2,200

ohms

139222

R8

330

ohms

139331

R9

22

ohms

139220

RIO

22

ohms

139220

Rll

39,000

ohms

139393

R12

560

ohms

139561

R13

39,000

ohms

139393

R14

560

ohms

139561

R15

22

ohms

139220

R16

22

ohms

139220

R17

2,200

ohms

139222

R18

330

ohms

139331

R19

2,200

ohms

139222

R20

100

ohms

139101

R21

100

ohms

139101

R22

22,000

ohms

139223

R23

2,200

ohms, 1 watt

136222

R24

560

ohms

139561

R25

100

ohms

139101

R26

1,800

ohms

139182

•R27

100

ohms

139101

R28

47

ohms,

carbon

comp.

119470

R29

1,000

ohms

139102

R30

470

ohms

139471

R31

220

ohms,

112 watt

133221

R32

1,800

ohms

139182

R33

100

ohms

139101

R34

47

ohms,

carbon

comp.

119470

R35

2,200

ohms, 1 watt

136222

R36

1

ohm,

5 watt, 10% w.w.

120010

R37

10

ohms

139100

R38

10

ohms,

2 watt

190100

R39

0.5

ohms,

1/2 watt

133509

R40

220

ohms,

1/2 watt

133221

R41

220

ohms,

1/2 watt

133221

R42

220

ohms,

1/2 watt

133221

R43

220

ohms,

112 watt

133221

R44

100,000

ohms,

1/2 watt

133104

R45

2.2

ohms,

112 watt

133022

PI

1,000

ohms

trimpot

100102

Fl

Fuse

5A

Slo-Blo

3AG

342050

F2

Fuse

5A, 3AG

341050

F3

Fuse

5A, 3AG

341050

F4

Fuse

2A, 3AG

341020

Tl

Power

Transformer

464002

T2

Power

Transformer,

International

464003

CI

10

mfd,

16 V,

non-polarized

electrolytic

203106

C2

390

pF,

500V,

Mica

257391

C3

0.001 mfd,

100V, Film

264102

C4

0.001 mfd,

100V, Film

264102

C5

470

mfd, 6.3V,

non-polarized

electrolytic

202477

C6

270

pF,

500V,

Mica

257271

C7

100

mfd,

80V,

Electrolytic

294107

C8

0.1 mfd,

100V, Film

264104

C9

680

pF,

500V,

Mica

257681

C10

100

mfd,

80V,

Electrolytic

294107

Cll

0.01 mfd,

100V, Film

264103

C12

0.1 mfd,

100V, Film

264104

C13

390

pF,

500V,

Mica

257391

C14

0.005

mfd,

1000V,

Disc

238502

C15

0.01 mfd,

1000V,

Disc

238103

C16

10,000

mfd, 75V,

Electrolytic

294103

C17

10.000

mfd. 75V.

Electrolytic

294103

C18

680

pF,

500V,

Mica

257680

C19

0.0047

mfd, 100V, Film

264472

C20

0.01 mfd,

100V, Film

264103

C21

0.01 mfd,

100V, Film

264103

Dl

1N4148

544148

D2

1N4148

544148

D3

1N4148

544148

D4

1N4148

544148

D5

1N4148

544148

D6

1N4148

544148

D7

1N4148

544148

D8

1N5240B

540510

D9

1N5240B

540510

D10

1N4148

544148

Dll

1N4003

544102

D12

1N4003

544102

D13

1N4003

544102

D14

1N4003

544102

DB1

Diode bridge

544252

Ql

2N5550

572550

Q2

2N5550

572550

Q3

2N5550

572550

Q4

2N5401

562401

Q5

2N5401

562401

Q6

2N5401

562401

Q7

2N5401

562401

Q8

2N5415

562415

09

NP2222

572222

Q10

2N5550

572550

Qll

2N3440

572440

Q12

2N3440

572440

Q13

2N5415

562415

Q14

2SK134

571134

Q15

2SK134

571134

Q16

2SJ49

561049

Q17

2SJ49

561049

15

All

resistors

are

1/4

watt

5% carbon

film

unless

otherwise

noted.

SPECIFICATIONS

Power

Rating: Less than 0.02% total harmonic distortion

at any power

level

up to 100

watts

continuous average

power per channel into 8 ohms at any frequency

bet-

ween 20 Hz and 20 kHz

with

both channels driven.

IM

Distortion

(SMPTE): Less than 0.005"* from 1 watt

to 100

watts

into 8 ohms.

Typical THD at 100

watts

into 8 ohms:

1 kHz — 0.0015%
10 kHz — 0.005^
20 kHz — 0.012^

Frequency

Response

into 8 ohms:

-

3 dB, 1 Hz to 100 kHz at 1 watt

±0.5dB,

10 Hz to 40 kHz at 100

watts

Typical Channel

Separation:

20 Hz: 66 dB

1 kHz: 66 dB
20

kHz:

60 dB

Signal

to

Noise

Ratio,

unweighted:

Better than 100 dB

at 100

watts

into 8 ohms.

Input

Impedance:

22,000 ohms.

Input

Sensitivity:

1.5 volts rms for 100

watts

into 8 ohms.

Damping Factor: 150 to 1 kHz into 8 ohms

50 to 10 kHz into 8 ohms

Rise

Time: 10 kHz, 60 volts peak to peak

square

wave,

\09< to

907c

: 2.5/is.

Slew

Rate:

10

kHz,

60 volts peak to peak

square

wave: 30

V/M s.

Semiconductor

Complement:

26 transistors, 8 power

Mosfets,

24 diodes, 4 zener diodes, 1 diode bridge.

Power

Consumption:

Quiescent: 101)

VA;

100

watts

into

8 ohms: 370

VA.

Size:

5-1/8" high, 16" wide, 10-1/2" deep.

Net

Weight

26 lbs.

Shipping

Weight:

30 lbs.

16

All

Specifications are subject to change without notice.

HAFLER

DH-200

STEREO POWER

AMPLIFIER

PICTORIAL

DIAGRAM

POWER TRANSFORMER

120

Volt

AC Line

Connections shown

OUTPUT MODULE ASSEMBLY

©COPYRIGHT

1980.

ALL

RIGHTS

RESERVED