manuals.online logo
Brands
  1. Home
  2. •
  3. Brands
  4. •
  5. Hafler
  6. •
  7. Amplifier
  8. •
  9. Hafler 2 Series User manual

Hafler 2 Series User manual

This manual suits for next models

1

Other Hafler Amplifier manuals

Hafler PRO5000 Owner's manual

Hafler

Hafler PRO5000 Owner's manual

Hafler PRO 1200 Guide

Hafler

Hafler PRO 1200 Guide

Hafler XL-600 User manual

Hafler

Hafler XL-600 User manual

Hafler 945 Series User manual

Hafler

Hafler 945 Series User manual

Hafler GX2800 User manual

Hafler

Hafler GX2800 User manual

Hafler SR2300 User manual

Hafler

Hafler SR2300 User manual

Hafler 9180 Series User manual

Hafler

Hafler 9180 Series User manual

Hafler XL-280 Service manual

Hafler

Hafler XL-280 Service manual

Hafler trans-nova 9505 User manual

Hafler

Hafler trans-nova 9505 User manual

Hafler 0915P User manual

Hafler

Hafler 0915P User manual

Hafler trans-nova P4000 User manual

Hafler

Hafler trans-nova P4000 User manual

Hafler HA75 User manual

Hafler

Hafler HA75 User manual

Hafler SERIES 2 DH-100 User manual

Hafler

Hafler SERIES 2 DH-100 User manual

Hafler JF2000 User manual

Hafler

Hafler JF2000 User manual

Hafler TransNova P3000 Owner's manual

Hafler

Hafler TransNova P3000 Owner's manual

Hafler DH-200 User manual

Hafler

Hafler DH-200 User manual

Hafler Trans Nova P7000 User manual

Hafler

Hafler Trans Nova P7000 User manual

Hafler HA15 User manual

Hafler

Hafler HA15 User manual

Hafler 9130 series User manual

Hafler

Hafler 9130 series User manual

Hafler P3100 User manual

Hafler

Hafler P3100 User manual

Hafler DH-110 Installation instructions

Hafler

Hafler DH-110 Installation instructions

Hafler DH-120 Service manual

Hafler

Hafler DH-120 Service manual

Hafler SE-100 User manual

Hafler

Hafler SE-100 User manual

Hafler SE120 User manual

Hafler

Hafler SE120 User manual

Popular Amplifier manuals by other brands

Magnat Audio EDITION FOUR Owner's manual/warranty document

Magnat Audio

Magnat Audio EDITION FOUR Owner's manual/warranty document

Inter-m PA-2000A Operation manual

Inter-m

Inter-m PA-2000A Operation manual

Yamaha TX6n owner's manual

Yamaha

Yamaha TX6n owner's manual

Peavey TNT 150 user guide

Peavey

Peavey TNT 150 user guide

Bosch LBB 1903/10 Installation and user instructions

Bosch

Bosch LBB 1903/10 Installation and user instructions

Avocent Emerge DA1200D Installer/user guide

Avocent

Avocent Emerge DA1200D Installer/user guide

Redgum RGi35 operating instructions

Redgum

Redgum RGi35 operating instructions

Cambridge Audio AXA25 user manual

Cambridge Audio

Cambridge Audio AXA25 user manual

Alpine MRP-M200 owner's manual

Alpine

Alpine MRP-M200 owner's manual

Technical Pro H1502UrBT user manual

Technical Pro

Technical Pro H1502UrBT user manual

FMS EMGZ307 operating manual

FMS

FMS EMGZ307 operating manual

Racal Instruments 5601 user manual

Racal Instruments

Racal Instruments 5601 user manual

Valcom V-1094A Technical specifications

Valcom

Valcom V-1094A Technical specifications

Cambridge Audio 851D user manual

Cambridge Audio

Cambridge Audio 851D user manual

QSC 3800 Specifications

QSC

QSC 3800 Specifications

NAD C300 owner's manual

NAD

NAD C300 owner's manual

Rotel RMB-1077 owner's manual

Rotel

Rotel RMB-1077 owner's manual

Peavey Monitor 300 Series operating guide

Peavey

Peavey Monitor 300 Series operating guide

manuals.online logo
manuals.online logoBrands
  • About & Mission
  • Contact us
  • Privacy Policy
  • Terms and Conditions

Copyright 2025 Manuals.Online. All Rights Reserved.

PREAMPLIFIER
Qpripc
9
DH-100
PREAMPLIFIER
OWNERS
MANUAL
LM163
THE
DAVID
HAFLER
COMPANY
Division
of
Rockford
Corp.
5910
Crescent
Boulevard,
Pennsauken,
New
Jersey
08109
613
South
Rockford
Drive
•
Tempe,
AZ
85281
Please
refer
to
this
serial
number
in
all
communications
regarding
this
equipment.
A
3838601
SPECIFICATIONS
(Specifications
stated
with
load
of
27K
ohms
in
parallel
with
1.5
nanofarads,
and
for
the
band
between
20Hz
and
20KHz
unless
noted.)
PHONO
PREAMP
SECTION:
Rated
Output:
3
Vrms
Maximum
Output:
8
Vrms
Harmonic
Distortion:
Less
than
0.005%
RIAA
Frequency
Response:
±
0.25
dB,
20-20
KHz
±0.1
dB,
40-20
KHz
Sensitivity:
10
mV
for
V
2
volt
@
Record
Out
Maximum
Input:
180
mV
@
1
KHz
Gain:
34
dB
@
1
KHz
Input
Impedance:
47.5
K
ohms
in
parallel
with
130
pF.
Signal/Noise
Ratio:
greater
than
100
dB,
‘A’
weighted.
LINE
AMPLIFIER
SECTION:
Rated
Output:
3
Vrms
Maximum
Output:
8
Vrms
Harmonic
Distortion:
less
than
0.005%
Frequency
Response:
±
0.25
dB,
20-20
KHz
Gain:
20
dB
Input
Impedance:
greater
than
35
K
ohms
Signal/Noise
Ratio:
greater
than
100
dB,
‘A’
weighted
Crosstalk:
down
80
dB
Separation:
greater
than
70
dB
@
1
KHz,
55
dB
@
10
KHz
Bass
Control:
±
10
dB
@
20
Hz,
moving
inflection
type
Treble
Control:
±
10
dB
@
20
KHz,
shelving
type
GENERAL
SPECIFICATIONS:
Semiconductors:
7
integrated
circuits,
5
diodes,
1
LED
Inputs:
Phono,
Tuner,
Aux,
Tape
Outputs:
Record,
Line
Controls:
Volume,
Balance,
Treble,
Bass,
Input
select
by
push
button,
Tape
Monitor,
Power
AC
Supply
Voltage:
95-130
or
190-260
VAC,
50-60
Hz.
Power
Consumption:
less
than
5
watts
AC
Convenience
Outlets:
2
switched
Size:
13-9/16
x
3
x
10
inches
Shipping
Weight:
9
lbs.
Net
Weight:
7
lbs.
DH100
FUNCTIONAL
DIAGRAM
WARNING:
To
prevent
fire
or
shock
hazard,
do
not
expose
this
equipment
to
rain
or
moisture.
©
Copyright
1988.
All
rights
reserved.
CONTENTS
Specifications.2
Functional
Diagram.2
Installation
.3
Component
List.4
Parts
Placement
Diagram.4
Schematic
Diagram.5
Additional
Parts
List.5
Operation.6
Notes
on
the
Circuitry.6
Additional
Information
.7j
Warranty
and
Service
Policy.8
INTRODUCTION
The
DH100
Preamplifier
must
surely
represent
the
highest
quality
per
dollar
of
any
audio
product
manufactured
in
this
decade.
Initial
response
to
the
performance
of
this
unit,
during
development
and
testing,
has
been
unusually
enthusiastic.
The
Puality
arises
from
the
meticulous
application
of
good
engineering
practice
—
respect
for
the
fragility
of
the
audio
signal;
simple,
straightforward
circuitry;
careful
component
selection
and
testing;
generous
circuit
card
topology,
and
use
of
precision
tolerances
where
they
contribute
significantly
to
performance.
The
design
philosophy
of
the
DH100
exemplifies
simplicity
and
economy.
To
achieve
this
we
have
provided
only
those
func¬
tions
that
are
primary
to
a
good
audio
system,
and
we
have
been
most
careful
to
see
that
the
integrity
of
the
electronics
con¬
forms
to
a
high
standard.
Although
it
might
be
thought
that
a
low-cost
preamplifier
would
not
find
its
place
among
higher-priced
components,
the
DH100
may
change
such
thinking,
for
its
ability
to
preserve
the
detail
rendered
by
expensive
cartridges,
power
amplifiers
and
loudspeakers
is
most
impressive.
We
invite
you
to
compare
its
performance
with
the
highest-rated
preamplifiers,
and
to
tell
us
of
your
findings.
INSTALLATION
1.0
MOUNTING
The
DH100
Preamplifier
is
intended
for
table
top
or
shelf
mounting.
No
rack
mount
provision
is
made.
It
is
important
that
the
Preamplifier
not
be
placed
directly
on
top
of
power
amplifiers
or
other
high-current
devices;
otherwise
hum
fields
may
be
intercepted
by
the
Preamplifier
and
heard
in
the
loud¬
speakers.
It
is
not
necessary
to
provide
much
ventilation
to
the
DH100,
however
it
is
a
good
rule
to
allow
air
circulation
around
any
electrical
device.
2.0
POWER
CONNECTIONS
Preamplifiers
are
supplied
with
transformers
for
standard
United
States
line
voltage.
Wide
variations
are
tolerated,
be¬
tween
100
volts
and
130
volts.
For
overseas
use,
an
Interna¬
tional
transformer
is
available
which
accommodates
line
voltages
between
200
and
260
volts
(Hafler
Part
Number
TA127).
It
is
recommended
that
the
Preamplifier
be
connected
directly
to
a
wall
or
floor
outlet,
and
not
to
an
extension
cord,
k
articularly
if
the
Preamplifier
is
being
used
to
switch
a
power
mplifier.
2.1
A
C
C
E
S
SORY
OUTLETS
Two
outlets
are
provided,
both
controlled
by
the
Preampli¬
fier
POWER
switch,
and
adequate
to
operate
a
DH-120,
XL-280
or
DH-500
power
amplifier
and
a
tuner
or
tape
transport.
In
some
countries
the
AC
convenience
outlets
are
not
provided.
3.0
OUTPUT
CONNECTIONS
Output
jacks
are
labeled
‘L’
for
left
channel
and
‘R’
for
right
channel.
3.1
LINE
OUTPUT
These
jacks
connect
to
the
power
amplifier
input
jacks
of
your
system.
The
signals
at
the
Line
Outputs
are
affected
by
the
BALANCE,
VOLUM
E,
BASS,
and
TREBLE
Controls
and
the
MUTING
circuit.
Note
that
the
DH100
is
not
meant
to
drive
audio
cables
longer
than
six
feet.
3.2
RECORD
OUTPUT
CONNECTIONS
These
are
signal
outputs
to
a
tape
recorder,
for
making
re¬
cordings
from
PHONO,
TUNER,
and
AUX
inputs.
You
will
use
a
‘line’
input
on
your
tape
recorder
(not
a
microphone
input!)
and
adjust
the
tape
input
level
controls
for
a
good
meter
reading.
Note
that
a
tape
recorder
or
other
signal
source
connected
to
the
TAPE
input
of
the
DH100
may
not
be
recorded.
The
MUTING
circuitry
does
not
protect
the
RECORD
outputs.
4.0
LINE
INPUTS
I
I
A
LINE
LEVEL
input
is
a
general
purpose
input
(as
opposed
o
an
equalized
input,
like
PHONO)
which
expects
a
standard
nominal
voltage
for
proper
operation.
Most
equipment
for
use
with
a
preamplifier
—
tuners,
tape
decks,
etc.
—
have
an
out¬
put
that
more
or
less
conforms
to
this
standard
voltage.
All
the
line
level
inputs,
TUNER,
AUX
(Auxiliary),
and
TAPE,
in
the
DH100
have
the
same
signal
capability
and
may
be
used
for
other
than
their
labelled
purpose.
For
instance,
a
tape
recorder
or
video
sound
source
may
be
connected
to
any
of
these
inputs.
The
‘sound’
output
from
most
home
computers
may
be
connected
to
these
inputs
as
well
(see
ADDITIONAL
INFORMATION.)
You
must
observe
Left
and
Right
Channel
symmetry
(ie:
connect
Left
to
Left
and
Right
to
Right)
between
the
DH100
and
any
signal
source
connected
to
it.
The
PHONO,
TUNER,
and
AUX
switches
are
self-cancelling;
that
is,
the
last
button
pushed
releases
the
previous
button.
Note,
however,
that
the
TAPE
switch
is
not
part
of
this
self¬
cancelling
group
and
that
it
supersedes
any
other
input
you
may
have
selected.
Be
certain
to
check
the
position
of
this
switch
if
your
preamplifier
sometimes
seems
inoperative.
Whilethenominal
signal
level
foralineinput
is50millivolts,
higher
level
signals
may
be
accommodated
because
they
pass
through
the
VOLUME
control
before
being
amplified.
The
input
impedance
is
approximately
35000
ohms.
When
a
tape
recorder
is
connected
to
the
RECORD
outputs,
this
im¬
pedance
will
drop
slightly.
Input
jacks
are
labelled
‘L’
(for
Left)
and
‘R’
(for
Right)
Chan¬
nel
signals.
5.0
PHONO
INPUT
The
PHONO
input
is
meant
to
accommodate
standard
mov¬
ing
magnet
cartridges
with
signal
outputs
in
the
5
millivolt
range.
Some
‘high
output’
moving
coil
cartridges
will
operate
satisfactorily
with
the
DH100
as
well,
although
VOLUME
set¬
tings
will
be
in
the
upper
third
of
the
range
of
that
control.
Nor¬
mally,
use
of
a
moving
coil
cartridge
will
require
a
pre-pream¬
plifier
(‘head
amp’)
or
step-up
transformer.
(Your
dealer
will
be
glad
to
tell
you
about
suitable
products
for
this
purpose.)
A
grounding
lug
is
provided
on
the
back
panel,
under
the
Right
PHONO
input,
normally
used
to
connect
the
ground
wire
from
the
turntable
to
the
Preamplifier
chassis.
(Sometimes
the
user
encounters
unpredicted
behaviorintheturntable-preamplifier
connection.
In
case
of
difficulty,
see
the
section
on
PHONO
in¬
stallation,
ADDITIONAL
INFORMATION,
later
in
this
Manual.)
5.1
CARTRIDGE
LOADING
The
input
impedance
is
47,500
ohms
in
parallel
with
130
picofarads.
This
resistance
value
is
standard
for
most
car¬
tridges.
The
capacitance
(130
pf)
when
added
to
customary
cable
capacitances
in
the
leads
between
turntable
and
preamplifier,
will
bring
the
total
capacitance
value
within
the
range
recommended
by
most
cartridge
manufacturers.
(To
‘customize’
these
input
specifications,
see
ADDITIONAL
IN¬
FORMATION.)
The
PHONO
input
is
‘guarded’
by
a
1
micro¬
farad
blocking
capacitor
(Cl)
to
protect
both
the
Preamplifier
and
the
cartridge.
THE
DAVID
HAFLER
COMPANY
will
not
assume
responsibility
for
equipment
damage,
of
any
kind,
if
this
capacitor
is
removed
or
defeated.
(See
ADDITIONAL
IN¬
FORMATION.)
3
(The
following
resistors
are
metal
film,
1/4W,
1%
unless
noted.)
d
£
?
£
0
x
Q_
8
in
co
s
in
t
**
co
in
in
co
in
i-
in
LO
CO
CM
Tf
^
1—
CM
in
CNI
CM
■
»-
*-><->000000
oo
oooo
z
2
5
0:525
O
OCDCOCtrOCOCDCGC
croc
^ocococ
o
o
o
o
o
5
2
2
5
5
1
cn
oc
tr
dc
tr
S3
wiQcoin^comcooiNCMcoN^
£
CM
CNICOt-t-^-^c^ScnJ^j^^j-ojuoCVJ
OOOOOOOOOOOOOi-
£^200000000000
CL
DC^^CCDCHDCDCDCQCQCirDCtE
<
—•
CO
C/5
<
?C
CO
D_
CO
0
E
<
O
oc
S
E
o
o
i-
cvi
co
co
to
to
w
E
E
E
E
.c
.c
_c
j=
E
o
o
o
o
^
*:
*:
*:
*
co
o
cm
^
o
1
-
00
P
CM
'T
P
5
C\l
Cl
r
r
<D
o
2
-
H
®
=J
CL
O
-2
>
o
£
1
<D
CO
E
*
■
2
8
g
x
gg"
o
z
5
<
CO
o
°
*
*
p
r-»
o
CM
&
CO
CO
I!
^
0
<
n
CO
CO
CO
E
E
sz
zz
o
o
*
o
CO
(0
tc
E
E
*
*
r-
in
<1)
_
E
o
o
*
c
in
®
5
£
El
E
fSjJcESSiiSSi
CO
CO
v-
e
o
e
1
I
1
c
|
=
I
8
|
8
|
S
Sj
"
^
$
JD
E
CD
I
E
E
I
E
_
y
^
CD
^
~
CM
£
O
*
I
£
O
«
°
o
!|
°
o
8
>-
U
o
U
<*>
p
-E
-Q
CO
q
CO
-2
o
°
o
o
n
CO
ill
^2
o
u
o
*
*
*
°°
8
^
i—
CO
CM
*3
0
^
.§
8
*
2
o
to
%
E
O
<D
CM
—
i-
CO
CD
E
o
5
5
S
CO
CO
h-
00
03
O
t-
CM
CO
i-
i-
CM
CM
CM
CM
CM
CO
M
in
(D
N
°
O
E
oi)
-
-
-
-
-
-
-
-
~
Lr
-
'
-
Tc
T-
i
°
CM
CO
^
in
to
N
DO
O
O
r-
'-CMCO^intONOOrrrr
t-
*“
t—
i—
r—
t—
CM
CM
docDccrocDcirirdtrtrir
cr
cr
oc
cc
cr
cr
cc
oc
CM
CM
CM
CM
CM
CM
g
3
cciririririiiirirciir
S
t
1
in
CO
CO
llJQ-NzdNCL
OOOQOqOOO
Q
Q
o
o
o
u_
CO
CD
00
00
CD
OOOO
>
>
>
O
>6
o
o
o
o
o
o
<OCO>COO
CDO
QQ^OQ^QQ
llllqllll^llll
22ll^:e£^So
coco^com^coinU-
coco
n
n
o
^
c
oo
cl
oof^qoi^oo^
ddM'ddMdoM
a
a
>,
a
Z
©
^
c
y
O
®
w
•^3
>,
T3
>.
CL
„
o
E
2
o
2
“
o
C
F
a
a
d
a.
E
p
cl
E
_
_>>_>>
o
_>>
co
a
>
CO
>
oo®oa3®oa5o
clclcdclocdclocl
o
o
O
o
o
o
O
o
o
cococococococococo
aaaaaaaaa
cococococococococo
OOOOOOOOO
O
JD
CD
§1
C
5
xf
^
CD
03
*“
IS
<
§
—
co
CO
CL
1
i
8
8
2
o
©
*
CD
CO
CL
3
o
a
03
03
03
CD
cr
cr
cM-'a-cocnoi-cO'^m
CMCMCMCMCOCOCOCOCO
OOOOOOOOO
o
r
in
to
s
OOOO
CD
CM
T-
CM
CM
CM
^
8
£
z
™
.
^OIQ-Q-ZQ-O.
JoOOOOqOO
Q_
>
>
8
Pis
>
o
->
CD
>
>
U.
d
Q
5
II
U.
^
5
as
2
o
S
®
8
P
P
i-OO
OZCLQQ_Q_Q_CL—l_IQ_
OOOOOOOOOOO
>
>
o
ppg^>
§
>
o
>
¥
in
in
n
*
Q
>
o
s
£
a
^
^
LL
8
5
O
O
d
i-
Q
Q
LL
LL
2
5
£
8
8
~
r-
o
Q
LL
LL
^
O
ll
LL
-
O
O
O
O
CM
LU
Z
o
Q_
s
o
o
o
o
3
®
to
a;
_
_
z
g
0
O
(j-
o
^
>.
p
>>
o.
a
a
>
cl
o
o
o
o
o
03
0
Q3
CD
Q3
ai
P
c
^
o
cl
jd
O
•
o
cl
cl
cl
p
a
a
o
co
o
1
2
||
2
CO
c
c
c
c
0
0
0
0
Q
>,
^
>,
5k
^
a
a
a
a
>
O
O
O
O
—
CL
O
CL
Q.
CL
O
CL
p
o
E
P
CL
0000®000®000000®®0
CL
CL
CL
CL
0
CL
CL
CL
0
CLQ.Q.CLCLQ
.0
0
CL
CL
CL
CL
o
0
0
0
0000000000000
aaaaaaaaaaaaa
0000000000000
oooooooooooooooooo
i-
cm
co
-*•
in
o
o
o
o
o
cm
co
io-
in
<30
o
t—
cm
co
in
05S?3r
£
P
t
?
^
r.
O
t"
CM
CO
M
IfT
CO
00
00
03
OOOOOOOOOOOOOOOOOO
DHIOTOIISCELLANEOUS
PARTS
riiflO)inc\i^ifiCMTrcM(D
“T-OOCOOJ(DT-CMi-!Din
tfXXXXXXXXXX
CL
0
O)
o
o.
£
£
i
2
oii
d
^
eg
co
.E
9
s2?|
r
O
"
CO
^
f
°
c
0
O
O
-*
c
>,
I-
s
<
o
^
—
10
>3
e-
^
QJ
^
c
°
0
T3
^
<5|?45
3
C
Z3
<-T
“!
r
c
3
3
£
C/5
*
z
z
0
<
CM
*7
co
o
03
0
3f
§
£
4
CO
n
o
>
©
2
S.
I
S
0
0
0-5
C/3
O
C/3
^
(DCOO)^SO)^COrW
mCOCOCOCMCM^-^tCMi-
T“
1
-
T-
1
—
T-T-l—
OOO
NNK1XXXX<<I—
xxxxxix^xx
co
n
o
a
0
'
.
CL
0
-C
CO
-^OO*-
O
c
c
©
0
0
Q)
©
CT>
0
c
=
<
<
5
C
-Q
0
-Q
=
3
<
X
CO
go
E
D
O
O
o)
I
1
I
|
o
o
®
$
O)
05
0
"E
0
Si
=
8|
8
%
5
I
2
X
X
C/3
_i
<
D_
O
It!
^(flUJWQJOQQWWN
C
0
o
0
0
_
_
0
"0
2
2
cl
*”
M
"
.
E
©-
0
^
25
O
o
n
c
©
_
o
9-
0
t;
n
“
E
“
7,
._
^
Cl
g=
r-
2
co
Tr
?0
©
6
5
5
2
?
2
§
S
5
§
OXXXLU^XXCOO
PREAMPLIFIER
DH100
SCHEMATIC
DIAGRAM
PC23B
SERIES
2
OPERATION
6.0
POWER
CIRCUITRY
When
the
DH100
is
turned
ON,
the
red
LED
will
illuminate
at
the
left
center
of
the
panel.
At
the
same
time,
an
internal
muting
circuit
will
limit
the
signal
passing
from
the
Preamplifiertoyour
power
amplifier
for
about
1.5
seconds,
until
the
Preamplifier
cir¬
cuits
have
stabilized.
During
this
1.5
seconds
you
may
hear
the
tuner
or
phonograph
or
other
selected
signal
at
greatly
reduced
level.
When
the
DH100
is
turned
OFF,
the
muting
circuit
engages
to
protect
the
power
amplifier
against
turn-off
tran¬
sients.
If
you
turn
OFF
the
Preamplifier
and
turn
it
ON
again
im¬
mediately,
the
muting
circuit
will
still
allow
only
reduced
output
for
1.5
seconds.
During
muting
time,
what
signal
you
hear
may
sound
distorted.
Such
distortion
is
normal
and
does
not
in¬
dicate
a
Preamplifier
problem;
it
will
disappear
when
muting
is
completed.
6.1
SIGNAL
SELECTION
PUSHBUTTONS
The
function
of
these
controls
has
been
discussed
in
Section
4.0.
The
Line
level
inputs,
TUNER,
AUX,
and
TAPE,
all
have
the
same
input
circuitry.
When
any
switch
is
NOT
selected,
its
input
is
left
‘floating’
(not
grounded,
as
in
most
preamplifiers)
but
an
isolating
ground
is
imposed
between
the
incoming
signal
and
the
Preamplifier
to
eliminate
inter-source
feedthrough.
The
reason
for
providing
this
kind
of
input
is
to
accommodate
signal
sources
that
will
not
tolerate
a
short
circuit
to
ground
at
any
time,
such
as
some
tape
recorder
and
computer
outputs.
6.2
VOLUME
CONTROL
This
control
has
a
smooth
continuous
rotation.
The
‘unity
gain’
position
(where
Line
input
and
output
voltages
are
the
same)
is
at
about
the
11
o’clock
setting
of
the
VOLUME
control.
6.3
TONE
CONTROLS
The
tone
circuit
in
the
DH100
is
unusual
in
three
respects;
it
is
not
switched
IN
or
OUT,
it
has
an
amplifier
dedicated
to
tone
operations
only,
and
it
uses
a
unique
balanced
circuit
to
obtain
boost
and
cut.
The
reason
many
preamplifiers
provide
tone
switching
is
that
tone
circuits
tend
to
interfere
with
the
bandwidth,
or
overall
fre¬
quency
response,
of
the
preamplifier.
This
is
not
the
case
in
the
DH100.
Neither
response
nor
distortion
are
deteriorated
by
the
tone
circuitry,
and
when
the
controls
are
in
their
center
(detented)
position,
response
is
flat
within
0.1
dB.
A
‘balanced’
circuit
is
obtained
by
using
an
operational
amplifier
in
a
differential
configuration.
This
type
of
control
per¬
mits
a
simple,
economical
parts
symmetry,
with
adequate
feed¬
back
for
low
distortion.
Precision
tolerances
are
used
in
this
cir¬
cuit
to
provide
a
flat
response
at
detent
position
and
to
provide
similar
characteristics
from
unit
to
unit.
The
controls
are
tapered
so
that
small
changes
will
occur
in
the
area
of
the
de¬
tent,
with
boost
or
cut
becoming
more
evident
as
the
control
is
moved
away
from
center.
As
a
general
rule,
extreme
settings
of
the
tone
controls
indicate
a
frequency
response
limitation
in
some
part
of
the
system,
usually
the
signal
source
or
the
loudspeaker.
When
high
settings
are
used,
it
is
most
likely
you
are
listening
to
large
amounts
of
hiss
and
rumble,
and
not
too
much
music.
The
minimum
amount
of
boost
and
cut
necessary
for
enjoyment
is
the
best.
6.4
BALANCE
CONTROL
The
BALANCE
control
adjusts
the
relative
amount
of
Left
and
Right
loudspeaker
volume.
We
find
that
customers
have
a
hesitation
in
using
this
control,
and
it
should
not
be
so.
The
pur¬
pose
of
balancing
the
sound
is
to
make
the
image
of
the
music
seem
centered
in
your
listening
area.
The
placement
of
the
speakers
and
furnishings
in
the
room,
your
listening
position
in
the
room
—
all
affect
the
position
of
the
stereo
image.
It
is
legitimate
to
use
the
BALANCE
control
to
make
this
image
comfortable
for
you.
Not
all
phonograph
recordings
and
broad¬
casts
are
balanced
at
their
source,
so
you
may
want
to
correct
for
this
with
the
BALANCE
control.
Usually,
experiment
will
dic¬
tate
a
normal
setting
in
your
room.
When
the
control
is
fully
clockwise
only
the
Right
Channel
in¬
formation
will
be
heard,
from
the
right
loudspeaker.
If
it’s
com¬
ing
from
the
left,
check
the
connection
of
your
cables.
Some¬
thing
is
reversed.
A
fully
counter-clockwise
setting
produces
only
Left
Channel
information,
from
the
left
loudspeaker.
The
center
detent
provides
equal
level
to
both
loudspeakers
with
an
accuracy
of
0.1
dB.
Careful
interconnection
is
the
best
way
to
insure
that
Left
in¬
formation
will
be
on
the
left
and
Right
information
on
the
right.
An
additional
check
can
be
made
if
you
own
recordings
of
a
symphony
orchestra,
for
virtually
every
orchestra
of
this
type
places
violins
on
the
left
and
cellos
on
the
right
of
the
stage.
Careful
listening
will
confirm
this
location
for
these
in¬
struments
if
Left
and
Right
signals
are
correct.
NOTES
ON
THE
CIRCUITRY
7.0
PHONO
STAGES
Two
operational
amplifiers
make
up
the
phono
section
of
the
DH100.
The
RIAA
equalization
is
passive
in
this
preamplifier,
which
means
that
feedback
is
not
used
to
determine
the
necessary
response
curve
for
playing
phonograph
records.
All
the
passive
components
in
the
PHONO
circuit
carry
1%
tolerances.
The
use
of
passive
circuitry
offers
considerable
design
freedom
when
using
integrated
circuits,
and
permits
these
‘chips’
to
function
adequately
in
a
quality
preamplifier
by
not
asking
a
single
chip
to
“do
too
much.”
Two
stages
also
pro¬
vide
exceptional
input-output
isolation
and
a
slightly
better
in¬
put
overload
characteristic.
The
gains
of
the
two
stages
have
been
selected
to
provide,
in
our
opinion,
the
most
practical
divi¬
sion
for
gain,
noise,
and
overload
specifications.
DC
coupling
has
been
preserved
to
eliminate
both
the
cost
and
compromise
of
yet
another
coupling
capacitor.
Special
care
has
been
taken
to
insure
close
tolerances
to
the
RIAA
characteristic
in
the
critical
mid-band
region.
7.1
POWER
SUPPLY
We
are
mindful
of
the
beneficial
influence
of
a
clean
power
supply,
with
good
dynamic
regulation
and
the
accompanying
low
impedance
at
all
audio
frequencies.
The
dual-tracking
regulator
in
the
DH100
tolerates
a
wide
range
of
line
voltage
variations.
To
maintain
a
low
impedance
at
high
frequencies
we
have
employed
low
ESR
electrolytic
capacitors
and
bypassed
the
power
carrying
traces
at
frequent
intervals
with
polypropy¬
lene
capacitors.
The
ground
traces
have
been
drawn
at
five
times
their
required
size,
to
ensure
very
low
ground
path
im¬
pedances.
7.2
SWITCHING
A
deliberate
effort
was
made
to
keep
the
number
of
switch
contacts
in
the
signal
path
to
a
minimum;
this
meant,
eventu¬
ally,
only
two
switches
for
each
signal
to
pass
through,
except
the
TAPE
input,
which
manages
with
only
one.
7.3
CAPACITOR
SELECTION
Capacitors
with
polypropylene
and
polycarbonate
dielec-
tries
have
been
used
wherever
possible
to
take
advantage
of
their
low
distortion.
Such
use
is
very
rare
in
economical
audio
components
and
contributes
significantly
to
the
sonic
qualities
oftheDHIOO.
6
ADDITIONAL
INFORMATION
8.0
The
following
paragraphs
discuss
some
of
the
answers
to
frequently-asked
questions
regarding
connection
of
peri¬
pherals
to
the
DH100
amplifier.
If
you
have
a
problem,
read
this
section
carefully
before
contacting
the
Factory.
8.1
PHONO
INPUT
CAPACITOR
Coupling
Capacitors,
Cl
(Left)
and
C101
(Right),
are
placed
at
the
input
to
the
Phono
stage
to
provide
DC
isolation
between
the
cartridge
and
the
input
amplifier.
The
value
is
1.0
mfd.
When
this
capacitor
is
jumpered,
thus
removing
it
from
the
circuit,
several
problems
may
arise.
Some
turntables
‘short’
the
car¬
tridge
leads
to
ground
when
the
tone
arm
is
in
the
rest
position.
With
the
capacitor
removed,
this
grounding
may
upset
the
‘balance’
of
the
Phono
amplifier
and
produce
a
dangerous
tran¬
sient
to
the
power
amplifier,
enough
to
damage
a
loudspeaker.
Other
times,
this
grounding
may
produce
an
unpleasant
hum.
There
is
a
small
and
usually
harmless
direct
current
flowing
from
the
input
stage
through
your
cartridge
without
this
capacitor,
but
unless
you
have
engineering
knowledge
of
the
parameters
involved,
you
cannot
rely
on
the
safe
value
of
this
current.
PLEASE
NOTE
THAT
THIS
MODIFICATION
(eliminat¬
ing
these
capacitors)
MAY
INVALIDATE
YOUR
WARRANTY.
8.2
PHONO
GROUNDING
Nearly
all
turntables
have
three
cables
connecting
them
to
the
preamplifier;
one
each
for
Left
and
Right
Channels,
and
a
third
single
wire
for
grounding.
The
single
wire
is
meant
to
be
secured
under
the
thumb
screw
below
the
Right
PHONO
input
jack.
A
bad
connection
at
this
point
will
surely
be
a
source
of
hum
and
must
be
corrected.
Hum
will
also
be
heard
if
the
Left
and
Right
Channel
plugs
are
not
firmly
seated
on
the
PHONO
jacks.
After
checking
all
the
conditions
stated
above,
if
your
system
hums
on
PHONO
but
not
on
any
Line
input,
turn
OFF
the
Preamplifier
and
reverse
the
line
plug
to
your
turntable.
Often
this
will
cure
the
problem.
As
a
rule,
it
does
not
help
hum,
anywhere
in
the
system,
to
ground
the
Preamplifier
to
an
‘earth’
ground,
such
as
a
water
pipe.
Good
grounds
like
this
are
hard
to
find,
and
such
a
connec¬
tion
often
makes
the
situation
worse,
particularly
in
the
case
where
there
is
Radio
Frequency
Interference
(RFI).
8.3
PHONO
INPUT
PARAMETERS
The
value
of
PHONO
input
resistance
(R1,
R101)
may
be
changed
if
necessary.
If
the
value
is
decreased
(less
than
47.5
K)
then
C1-C101
will
have
to
be
increased
to
preserve
the
frequency
response.
If
R1-R101
are
increased,
the
input
capacitors
will
not
have
to
be
changed,
and
the
low
frequency
response
will
im¬
prove
slightly.
Seethe
Parts
Placement
Diagram
for
the
position
of
these
resistors.
The
input
loading
capacitors,
C2,C102
may
also
be
changed
if
necessary.
The
total
load
capacitance
on
a
cartridge
is
the
algebraic
sum
of
three
separate
capacitances;
a)
the
capacitance
of
the
cable
between
the
turntable
and
the
Preamplifier,
b)
the
value
of
C2
or
C102,
and
the
input
capacitance
of
the
DH100
phono
stage
without
C2.
Typical
cable
value
is
150
pf.
a)
150
Present
value
is
120
picofarads.
+
b)
120
Input
value
without
C2
is
10
pf.
+
c)
10
Total
capacitance
=
280
pf.
Required
values
for
proper
cartridge
loading
can
lie
between
100
and
470
picofarads.
While
it
is
desirable
to
have
the
value
close
to
the
manufacturer’s
recommendation,
this
value
is
not
critical.
When
replacing
these
components,
use
a
good
polypropylene
capacitor
for
Cl
and
C2,
and
a
metal
film
resistor
for
R1.
8.4
M
O
N
O
OPERATION
A
preamplifier
in
MONO
mode
usually
combines
the
Left
and
Right
Channel
information
and
delivers
this
summed
signal
to
both
outputs.
Its
use
is
limited
to
older
phonograph
recordings
and
to
a
few
inputs
which
are
available
in
MONO
only,
such
as
a
monaural
tape
deck,
video
sound
signal,
and
computer
sound
outputs.
There
are
two
options
open
to
the
user
if
a
MONO
source
is
to
be
used.
The
easiest
option
is
to
connect
the
signal
to
the
Left
input
jack
and
listen
to
the
source
with
the
BALANCE
control
fully
counterclockwise.
Or
the
BALANCE
control
may
be
set
at
center
and
a
grounding
plug
inserted
in
the
Right
input
jack.
In
either
case,
only
the
Left
loudspeakerwill
be
active.
If
one
mono
signal
is
applied
to
AUX
left,
and
one
to
AUX
right
jacks,
then
the
BALANCE
control
will
select
one,
the
other,
or
a
mixture
of
the
two
—
two
inputs
for
one.
A
more
satisfactory
input
configuration
is
through
the
use
of
a
‘Y’
interface
cable.
This
device
accepts
a
mono
input
plug
and
branches
out
to
two
plugs,
one
each
for
the
Left
and
Right
Preamplifier
jacks
on
a
Line
input.
The
advantage
is
that
both
loudspeakers
will
reproduce
the
mono
signal
source.
In
this
case,
only
one
device
may
be
connected
per
Line
input.
Home
computers
with
sound
output
may
be
connected
to
the
DH100.
Such
outputs
vary
widely
from
one
computer
to
another,
so
you
will
have
to
consult
a
dealer
or
the
computer
schematic
diagram
to
see
what
the
signal
parameters
are.
We
have
eliminated
one
potential
problem
for
you
by
seeing
to
it
that
the
input
signal
is
never
grounded
when
not
in
use.
Keep
in
mind
that
the
computer
output
level
may
be
much
higher
than
typical
for
audio
components.
In
this
case
a
resistive
voltage
divider
may
be
used
to
reduce
the
signal
level.
FIG
8.4
shows
a
typical
connection.
Ry
should
be
kept
at
10000
ohms,
and
Rx
varied
for
a
good
signal
level.
It
would
be
possible
to
adjust
Rx
so
that
computer
level
is
the
same
as
the
TUNER
or
PHONO
at
similar
VOLUME
control
settings.
FIG
8.4
also
shows
Rx
and
Ry
com¬
bined
in
a
level
control
potentiometer
which
must
be
mounted
exterior
to
the
Preamplifier,
perhaps
in
a
junction
box
of
some
kind.
+v
c
8.5
FIG
8.4
COMPUTER
INTERFACE
c
t
Rx
_
.
0
M
-Ml—-1
—
C
Ry
J
r-
3
C
=
1-5
mF
R
=
4.7
K
R
*1
V
c
=
5
-
12
V
«-
if
*
>
To
AUX
i—J
HEADPHONE
CONNECTION
The
DH100
has
no
output
jack
for
headphones.
The
Line
out¬
puts
will,
however,
drive
high
impedance
headphones
(200
to
2000
ohms)
to
a
level
satisfactory
for
normal
listening.
It
is
assumed
that
if
you
use
the
DH100
for
headphone
listening,
you
are
not
also
using
it
with
a
power
amplifier.
The
DH100
controls
make
it
a
very
good
preamplifier
for
headphone
use.
There
are
conversion
‘boxes’
available
from
your
dealer
for
connecting
headphones
to
the
power
amplifier
and
these
will
prove
to
be
a
satisfactory
way
to
use
both
loudspeakers
and
headphones
on
the
same
system,
including
standard
low
impedance
phones
(4
ohms).
8.6
PREAMPLIFIER
OUTPUT
CAPACITOR
In
this
day
of
higher
and
higher
audio
power,
protection
cir¬
cuitry
is
a
most
important
feature
of
HAFLER
equipment.
The
protection
circuitry
in
our
preamplifiers
and
power
amplifiers
is
meant
for
the
benefit
of
both
these
units
and
your
valuable
loudspeakers.
For
this
reason
you
should
never
defeat
the
coupling
capacitors
in
a
HAFLER
preamplifier
or
power
amplifier.
The
DH100
Muting
circuitry
requires
the
coupling
capacitor
to
prevent
DC
output
to
the
power
amplifier.
REMOVAL
OF
THIS
CAPACITOR
MAY
INVALIDATE
YOUR
WARRANTY.
7
SERVICE
POLICY
AND
LIMITED
WARRANTY
The
DH100
Preamplifier
has
been
carefully
designed
to
pro¬
vide
many
years
of
use
without
maintenance
or
service.
Factory
assembled
units
undergo
rigorous
testing
before
they
are
ship¬
ped.
However,
damage
in
transit
and
human
error
can
intervene
to
make
service
necessary.
It
is
the
owner’s
responsibility
to
return
the
unit,
freight
prepaid
and
insured,
to
the
factory,
or
to
the
nearest
factory
authorized
service
facility.
Units
shipped
freight
collect
will
not
be
accepted.
Shipment
should
be
made
by
United
Parcel
Ser¬
vice
(UPS)
wherever
possible.
We
will
not
be
responsible
for
damage
incurred
in
shipments
by
Parcel
Post;
repairs,
in
this
case,
will
be
made
solely
at
the
owner’s
expense.
All
shipments
should
be
insured
for
the
full
value
of
the
unit.
Use
the
original
carton
and
packing
material,
and
enclose
all
of
the
following:
a)
Complete
shipping
address
(PO
Box
numbers
are
not
ac¬
ceptable),
b)
Serial
number
(if
not
on
unit)
c)
Copy
of
dated
Bill
of
Sale,
for
Warranty
service.
d)
Description
of
malfunction.
If
it
is
intermittent,
indicate
this!
Warranty
service
is
guaranteed
for
90
days.
Warranties
apply
to
the
original
purchaser
only
and
are
void
if
the
Preamplifier
has
been
modified
without
factory
consent,
or
if
parts
have
been
substituted
which
the
factory
considers
unsuitable,
or
if
the
Preamplifier
has
been
physically
or
electrically
abused
or
used
for
some
purpose
for
which
it
was
neither
designed
nor
intended.
WARRANTY
FOR
FACTORY-ASSEMBLED
UNITS:
A
factory
assembled
DH100
is
warranted
for
3
full
years
from
purchase
date,
including
parts,
labor
and
normal
return
ship¬
ping
costs
to
the
owner
within
the
continental
United
States.
The
owner
is
responsible
for
shipment
to
the
factory
or
authoriz¬
ed
service
facility,
and
must
submit
a
copy
of
the
dated
bill
of
sale
when
warranty
service
is
requested.
WARRANTY
FOR
KIT-BUILT
UNITS:
The
parts
supplied
in
a
DH100
kit
are
warranted
for
one
full
year
from
the
purchase
date.
If
a
defective
component
is
found
on
a
circuit
board
or
in
the
kit,
simply
return
the
i
ndividual
part
to
the
factory
prepaid,
together
with
the
serial
number
and
the
date
of
purchase.
It
will
be
replaced
at
no
charge.
If
you
cannot
locate
the
cause
of
a
problem
in
your
DH-100K,
return
it
to
the
factory
(with
a
copy
of
the
dated
bill
of
sale
if
in
warranty)
and
a
money
order
for
$35.
Personal
checks
must
first
clear.
VISA
and
Mastercharge
can
be
processed
by
phone
with
your
daytime
phone
number.
If
the
difficulty
is
solely
a
defective
part,
the
unit
will
be
repaired
and
returned
to
you
prepaid
together
with
the
amount
of
your
payment
less
a
charge
for
packing
and
shipping.
If
the
problem
is
found
to
be
an
error
in
kit
assembly,
the
unit
will
be
put
in
proper
working
order
and
re¬
turned
to
you,
prepaid
within
the
continental
USA.
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
or
silver
core,
or
paste
flux,
will
be
returned
unserviced.
This
warranty
gives
you
certain
rights.
You
may
also
have
other
rights,
the
extent
of
which
may
vary
from
state
to
state.
5910
CRESCENT
BOULEVARD,
PENNSAUKEN,
NJ
08109
•
609/662-6355
Division
of
Rockford
Corp.
•
613
South
Rockford
Drive
•
Tempe,
AZ
85281
THE
HAFLER
DH-100
PREAMPLIFIER
KIT
BUILDER’S
MANUAL
LM164
ASSEMBLY
INSTRUCTIONS
There
are
three
basic
rules
for
success
in
electronic
kit
building:
1.
Read
the
instructions
carefully,
and
follow
them
in
or¬
der.
2.
Make
secure
solder
connections
which
are
bright
and
smooth.
3.
Check
your
work
carefully
after
each
step.
The
DH-100
preamplifier
is
a
versatile
component
with
sophisticated
circuitry
which
has
been
made
remarkably
easy
to
build
by
individuals
with
many
years
of
experi¬
ence
in
the
design
and
engineering
of
the
finest
perform¬
ing
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.
Fatigue
increases
the
risk
of
error,
so
take
a
break
rather
than
push
to
early
completion.
There
are
relatively
few
separate
components
in
this
design,
to
make
it
easy
to
pack
everything
away,
if
need
be.
Your
work
area
should
have
good
lighting
and
the
pro¬
per
tools.
The
tools
should
include:
1.
A
40
to
60
watt
pencil
soldering
iron
with
a
3/16"
or
smaller
tip
which
reaches
700°F.
.
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.
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
operating
temperature
each
time
it
is
switched
on,
poor
solder
connections
are
more
likely.
Pencil
irons
are
much
lighter
and
easier
to
use,
and
there
is
no
waiting
time
when
solder
connections
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
make
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
lug,
or
circuitry
on
the
board,
with
the
bright,
shiny
tip
of
the
iron.
3.
After
heating
for
a
couple
of
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
solder¬
ing.
Connections
to
the
circuit
board,
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”
par¬
tially
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.
Continued
on
back
page.
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
occasion¬
ally
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
conductors,
any
movement
must
be
avoided
for
a
few
seconds
to
allow
a
good
bond.
When
cool,
check
the
connection
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
elec¬
tronic
work.
Silver
solder
is
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
cir¬
cuit
pattern
from
the
board.
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
onto
adjacent
circuitry
and
cause
a
short
circuit.
Assembly
Tips
A
‘set’
of
hardware
includes
a
screw
and
a
KEP
nut
(which
has
a
lockwasher
attached).
Always
install
the
lockwasher
side
first.
Screws
are
always
inserted
from
the
outside
of
the
chassis
unless
otherwise
specified
in
the
instructions.
#4
hardware
is
smaller
than
#6,
and
in
this
kit,
the
#6
screws
are
finished
in
black,
to
match
the
cover.
To
‘prepare’
a
wire
means
that
you
are
to
cut
the
desig¬
nated
length
from
that
color
supplied,
and
strip
about
1/4"
of
insulation
from
each
end.
The
wire
supplied
in
the
kit
is
#18
white,
and
#22
red
and
green,
so
you
can
set
adjust¬
able
wire
strippers
accordingly.
The
line
cord
is
#16.
Be
careful
that
you
do
not
nick
the
wire
when
you
strip
it
(that
can
happen
more
easily
when
you
do
not
use
wire
strip-
pers),
for
that
weakens
it.
The
wire
supplied
in
the
kit
is
‘bonded
stranded,’
which
provides
greater
flexibility
with
resistance
to
breakage
for
easier
use.
Whenever
a
connection
is
to
be
soldered,
the
instruc¬
tions
will
so
state,
or
will
indicate
by
the
symbol
(S).
If
more
than
one
wire
is
to
be
soldered
at
the
same
point,
the
indication
will
be
(S-2)
or
(S-3).
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,
but
some
builders
prefer
to
solder
each
connection
as
they
go.
Every
connection
in
the
kit
will
be
soldered
when
it
is
complete.
Every
lead
which
connects
to
a
hole
on
the
circuit
board
is
to
be
soldered.
After
soldering
a
connection,
clip
off
any
excess
lead
length
for
neatness,
and
to
minimize
the
possibility
of
a
short
circuit.
‘Tinning’
refers
to
the
process
of
applying
a
light
coat¬
ing
of
solder
to
a
bared
wire
end.
On
the
line
cord,
for
example,
it
keeps
all
the
strands
secured,
and
also
makes
a
good
connection
easier.
Simply
touch
the
wire
with
the
iron
for
a
couple
of
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,
as
it
is
pre-tinned.
It
is
a
good
idea
to
check
off
all
the
parts
before
you
(
begin,
to
make
sure
that
nothing
has
been
overlooked,
and
to
help
you
identify
any
unfamiliar
items
by
compar¬
ing
them
with
the
list
for
each
parts
bag,
and
with
the
pictorial
diagram.
If
a
part
is
missing,
a
postcard,
or
a
phone
call
to
Customer
Service
at
(609)
662-6084
will
bring
a
prompt
response.
KIT
PARTS
LIST
This
list
is
in
addition
to
the
individual
lists
included
in
each
of
the
parts
bags,
#1
through
#4.
Part
No.
Part
No.
1
Circuit
board
assembly,
PC-23
KF343
1
Fuse,
spare,
1/16
amp
slo-blo
SF019
1
Cover
MS174
2
End
cap,
front
panel
MC111
1
Back
panel
MS199
4
Knob,
metal
HD117
1
Bottom
plate
MS173
1
Line
cord
with
plug
WA043
1
Front
panel
ME118
1
Transformer,
power,
120
volt
TA126
1
Front
sub-panel
MS169
or
alternate
240
volt
TA127
2
Side
pieces
MS171
1
Label,
serial
number
LR015
1
Allen
wrench,
L-shape,
5/32"
HZ138
1
Registration
card
LM016
1
Allen
wrench,
L-shape,
#8
set
screw
HZ139
1
Owner’s
Manual
1
Cable
pair,
audio
WA017
n
°n
THE
i
ra
U
/company
5910
Crescent
Boulevard
•
Pennsauken,
New
Jersey
08109
•
609/662-6355
Division
of
Rockford
Corp.
•
613
South
Rockford
Drive
•
Tempe,
AZ
85281