Adcom GFA-4302 User manual

ADEM
a)
CAR
AUDIO
AMPLIFIERS
OWNER’S
MANUAL
GFA-4302
GFA-4402
GFA-4304
GFA-4404
GFA-4702

IMPORTANT:
Be sure to connect the
POWER and GROUND
correctly! Warranty will be
affected if the amplifier is
incorrectly connected!
INSTALLATION ADVISORY: Clipped strands
of power or speaker wire could enter the
amplifier through the Free-Flow perforated
sleeve. Be sure to clip wires well away from
the amplifier to avoid this possibility
Features and specifications subject to change without notice. ADCOM Car Audio is a
registered trademark of ADCOM. All rights reserved. ©1994 ADCOM Inc.

> AOWNER'S
ADCOM
MANUAL
Congratulations!
And
thank
you
for
choosing
ADCOM
Car
Audio
Amplifiers
for
your
mobile
sound
system.
Your
ADCOM
Car
Audio
Amplifier
uses
superior
engineering
principles
and
the
highest
quality
components
to
provide
a
musical
experience
with
clarity
and
dynamics
never
before
achieved
in
a
vehicle.
PLEASE
read
this
manual
entirely
before
attempting
to
install
this
product.
Due
to
the
sophisticated
nature
of
this
equipment,
we
highly
recommend
using
an
authorized
ADCOM
Car
Audio
Dealer
to
achieve
the
maximum
performance
from
your
mobile
sound
system!
Your
warranty
is
affected
if
you
choose
to
install
your
ADCOM
amplifier
yourself.
You
will
only
receive
all
the
benefits
of
the
limited
warranty
if
the
amplifier
is
professionally
installed
by
an
authorized
ADCOM
Car
Audio
Dealer!
Please
refer
to
your
warranty
card
for
further
details.
GFA-4302 GFA-4402 GFA-4304 GFA-4404 GFA-4702
Power
Output
30
W/Ch
@
20
W/Ch
@
40
WICh
@
70
WICh
@
2Ohms Stereo | <0.25% THD* | <0.25% THD* | <0.25% THD* | <0.25% THD* | <0.2% THD*
40hms Mono $ <0.25% THD* | <0.25% THD* | <0.25% THD* | <0.25% THD* | _<0.2% THD*
Frequency
OHz-50KHz
|
OHz-50KHz
|
OHz-SOKHz
Response
+0dB,
-3dB
+0dB,
-3dB
+0dB,
-3dB
+0dB,
-3dB
+0dB,
-3dB
Power
OHz-50KHz
OHZ-5UKHZ
QHZ-SOKHZ
OHz-SOKHz
Bandwidth +0dB, -3dB Í +0dB,-3dB | +0dB,-3dB | +0dB,-3dB | +0d8, -3dB
Input Impedance | a5KOhms | a5kOhms | askOhms | 85KOhms | 8.5 K Ohms
Input Sensitivity | 400mV to 2v | 400mV to 2V 60OMV to 2V
Separation >90 dB >90 dB
S/N Ratio 2100 u5 > 100 dB
Damping Factor aso | sœ | o æo |] eo
idle Current 3 Amps 10 Amps
Fuse Size 20 Amp 50 Amp 50 Amp
Weight 8 Ibs (3.7kg) | 10 Ibs (4.6kg) | 12 Ibs (5.5kg) | 19 lbs (8.7kg) | 32 Ibs (14.6kg)
Dimensions 9.75x10.75x2.3" | 9.75x12.76x2.2" | 9.75x14.75x2.3" | 9.75x24.25x2.3" | 9.75x24.25x2.3"
in inches WxLxH WxLxH WxLxH WxLxH 9.75x15.5x2.3"
* THD Ratings measured between 20Hz and 20khz

HOW TO USE THIS MANUAL
This manual is divided into three distinct sections:
Section 1: Common features, instructions and connections for all
ADCOM Car Audio amplifiers.
Section 2: Installation instructions for the GFA-4302 and GFA-4402
(These amplifiers use RCA type input connections)
Section 3: Installation instructions for the GFA-4304, GFA-4404 and
GFA-4702 (These amplifiers use 5-pin XLR type input
connections)
In Sections 2 and 3 there are diagrams to help install ADCOM Car
Audio amplifiers in the most popular configurations. If a more extensive
installation is required, it is recommended that your authorized ADCOM Car
Audio dealer perform the installation. Technical support is available in our
Customer Service department by calling [phone] 9am to 5pm EST.
SECTION 1: Common Features
UNPACKING:
Below is a list of what is included with each model amplifier:
GFA-4302 and GFA-4402 GFA-4304 and GFA-4404
1 Amplifier 1 Amplifier
1 Owner’s Manual 1 Owner’s Manual
1 Warranty Card 1 Warranty Card
1 In Line Fuse Holder 1 In Line Fuse Holder
2 RCA Shorting Plugs 2 GFY-4 XLR/RCA Adapters
GFA-4702 (Amp Section) GFA-4702 (Power Supply)
1 Amplifier Section 1 Power Supply Section
1 Owner's manual 1 Warranty Card
1 GFY-4 XLR/RCA Adapter 1 GFC-1 Power Cable
If anything is missing from your carton, please contact your dealer or
call us directly. Be sure to verify that the serial number printed on the bottom of
the amplifier is the same as the serial number on the carton. If either number is
missing or altered, you shouid contact ADCOM immediately at [phone].
Before each ADCOM Car Amplifier leaves our facility in New Jersey, it is carefully
inspected for physical imperfections and electrical performance as a routine part
of ADCOM'’s Quality Assurance system. This is to ensure flawless performance
and appearance when you receive it.

After
you
have
unpacked
your
amplifier,
inspect
it
for
physical
damage.
In
the
unlikely
event
that
damage
has
occurred
during
shipping,
a
freight
claim
to
cover
shipping
damage
can
be
initiated.
THE
RIGHT
A
TO
CLAIM
AGAINST
A
PUBLIC
CARRIER
CAN
BE
FORFEITED
IF
THE
CARRIER
IS
NOT
NOTIFIED
PROMPTLY
AND
IF
THE
SHIPPING
CARTON
AND
PACKING
MATERIAL
ARE
NOT
AVAILABLE
FOR
INSPECTION.
SAVE
ALL
PACKING
MATERIAL
UNTIL
THE
CLAIM
HAS
BEEN
SETTLED.
MOUNTING:
Ail
audio
components
in
a
vehicle
should
be
securely
mounted,
as
they
could
become
airborne
in
the
event
of
a
collision;
Serious
injury
could
occur.
ADCOM
Car
Audio
amplifiers
may
be
mounted
almost
anywhere;
every
model
is
fan-cooled,
so
mounting
possibilities
are
limited
only
by
your
imagination.
Follow
these
simple
guidelines
to
ensure
long
life,
cosmetic
integrity
and
sonic
dependability:
1.
Always
securely
mount
the
component
to
a
flat
surface
using
all
mounting
holes.
2.
Never
mount
an
audio
component
where
loose
objects
can
come
in
contact
with
it.
3.
Never
mount
an
amplifier
under
a rug,
mat
or
carpet.
Remember,
the
better
the
ventilation,
the
less
chance
your
amp
will
thermally
shut
down!
When
mounting,
do
not
use
the
amplifier
as
a
drilling
template.
Use
as
a
marking
template,
only.
When
mounting
an
amplifier,
use
only
Pan-Head
screws,
not
beveled
head,
and DO
NOT
OVER-TIGHTEN!
Pan Head Screw <p
CONNECTING
POWER:
|
ADCOM
amplifiers
are
designed
to
be
used
with
12
Volt,
negative-
ground
vehicles.
The
first
step
is
to
disconnect
the
Ground(-)
battery
terminal!
The
positive
and
negative
gold-plated
power
connectors
on
the
amplifier
will
accommodate
up
to
GAWG
wire.
8AWG
cabie
is
the
standard
gauge
and
will
fit
with
the
insulation
into
the
power
connectors.
If
more
than
one
amp
is
being
installed,
use
4AWG
from
the
battery
to
a
power
distribution
block.
Run
BAWG
from
the
distribution
block
to
each
amplifier.
All
ground
connections
should
be
as
short
as
practically
possible
and
terminated
at
the
same
location.
A
fuse
or
protection
device
MUST
be
in
the
+12
Volt
power
cable
within
18”
of
the
battery.
It
should
also
be
readily
accessible.
An
additional
fuse
holder
may
be
located
within
18”
of
the
amplifier
or
power
distribution
block.
The
fuse
near
the
battery
is
to
protect
your
vehicle.
An
optional
fuse
near
the
amplifier
is
to
help
protect
the
amplifier!
When
a
fuse
blows,
replace
ONLY
with
an
identical
amperage
fuse!
Connect
the
IGN
terminal
on
the
amplifier
to
the
source
unit’s
power
antenna,
remote
or
amp-turn-on
lead.
When
the
source
is
turned
on,
it
supplies
12
volts
to
the
IGN,
which
turns
the
amplifier
on.
If
two
or
more
components
are
being
turned
on
by
the
remote
lead,
it
is
suggested
to
“relay”
the
turn
on.
(see
Fig.
1)
Here,
the
relay
(Bosch
0-322-204-150
or
P&B
VF4-45F11)
is
triggered
by
the
remote
lead
which
sends
current
to
the
IGN
connections.
This
is
considered
a
good
installation
technique
and
a
SPDT
relay
is
readily
available
from
most
installation
shops.

From
source
unit’s
“Power
Antenna”
or
“Remote”
lead
To “IGN” or “Turn-On” terminal of
all Amplifiers, GFis and processors
To constant +12 Volts (B+ or power
distribution block)
Fig. 1
Chassis
Ground 86=] 30
SPEAKER CONNECTIONS:
ADCOM
uses
gold-plated
speaker
connectors
that
will
accommodate
up
to
8AWG
speaker
wire.
Standard
speaker
wire
gauge
is
12AWG
to
16AWG
and
will
fit
easily
into
the
terminals.
Be
sure
there
are
no
frayed
or
loose
wire
strands
that
may
end
up
touching
other
wires.
Speaker
polarity
is
clearly
marked;
special
attention
must
be
taken
while
connecting
speakers.
Speaker
polarity
is
essential
to
proper
amplifier
operation!
Any
number
of
speakers
may
be
used
with
your
ADCOM
Car
Audio
amplifier.
The
“system
impedance”
is
dependent
on
the
wiring
configuration
and
selection
of
speakers.
Although
ADCOM
amplifiers
are
stable
into
loads
of
less
than
%
Q,
continuous
operation
into
impedances
lower
than
2
Q
may
eventually
lead
to
thermal
overload,
causing
the
amplifier
to
shut
down
until
it
cools
off.
Your
authorized
ADCOM
Car
Audio
dealer
is
best
able
to
maximize
the
performance
of
your
system
by
calculating
impedance
and
ensuring
the
proper
connection
of
all
system
components.
MoSt™ CONFIGURATION:
ADCOM
Car
Audio
amplifiers
are
capable
of
running
stereo
and
mono
configurations
simultaneously.
In
order
to
achieve
this,
one
channel
must
be
inverted
at
the
input.
Inverting
simply
means
making
the
positive
lead
negative,
and
the
negative
lead
positive.
For
consistency,
we
recommend
that
the
“B”
or
“RIGHT”
channel
be
inverted.
In
addition,
the
same
channel’s
output
must
be
inverted
to
complete
the
process.
Inverting
techniques
will
be
discussed
in
sections
2
and
3.
INPUT SENSITIVITY SETTING:
Located
on
the
end
panel,
along
with
the
input
connectors,
are
two
small
openings
that
house
the
input
sensitivity
controls.
THEY
ARE
NOT
AMPLIFIER
VOLUME
CONTROLS!
When
properly
set,
they
match
the
output
of
the
source
unit
with
the
input
of
the
amplifier.
If
you
wish
to
have
the
amplifier

and source unit properly matched, consult your authorized ADCOM Car Audio
dealer.
Optimal performance and the advantages of “passively terminated
balanced” inputs are realized when sensitivity controls are turned fully
clockwise. Since the sensitivity controls affect only the positive inputs, the
controis MUST be fully clockwise in the MaSt™ or mono configurations.
CARE AND CLEANING:
Great care has been taken by ADCOM to assure that your amplifier is
as flawiess in appearance as it is electrically. in the event that your ADCOM
amplifier needs cleaning, use a damp cloth or dry, soft bristled paint brush. Do
not use cleaning fluids of any kind as damage to the finish may result. Treat this
product as a precision instrument, and it will provide you with many years of
musical enjoyment.
If you experience any problems with your ADCOM Car Audio amplifier,
please contact your local authorized dealer or call ADCOM Customer Service at
[phone] between 9am and 5pm EST. Ask for Technical Assistance for car
audio.
SECTION 2: RCA Input Amps
INPUT SECTION:
it may seem unusual to find 4 RCA inputs on a 2 channel amplifier, but
that is just what you will find when you inspect the ADCOM GFA-4302 or GFA-
4402 amplifiers. Channel “A” is the “LEFT” and channel! “B” is the “RIGHT”. The
inputs on the left side are the (+)positive inputs and the inputs on the right side
are the (-} negative inputs. If you wish fo run these amplifiers in the Balanced
mode, it is strongly suggested that an authorized ADCOM Car Audio dealer
handle this installation!
There are two ways to run RCAs into these amplifiers. For stereo
operation, RCAs connect to the left-most input jacks, labeled A+ and B+. When
using the amplifier in either a bridged Mono or MoSt™ configuration, the upper
left and lower right inputs, labeled A+ and B-, are used. Always insert the
included RCA Shorting Plugs into unused RCA inputs!

WIRING DIAGRAMS:
There are 3 basic wiring schemes for the GFA-4302 and GFA-4402:
they are as follows:
1. Stereo
2. Mono
3. MoSt™ (Mono/Stereo simultaneously)
In the Stereo _ mode, the RCA interconnect cables connect to the
Amplifier
as
follows:
The
left
cable
to
A+
input
and
the
right
cable
to
B+
input.
Speakers
hook
up
normally:
“A+”
and
“A-”
outputs
to
LEFT
speaker(s)
(+)pos
&
(-)neg,
and
“B+”
and
“B-”
outputs
to
the
RIGHT
speaker(s)
(+)pos
&
(-)neg.
See
Fig.2.
Remember
to
insert
the
RCA
Shorting
Plugs
in
the
unused
inputs.
BE
CERTAIN
OF
POWER/GROUND
CONNECTIONS
Fig. 2

In
the
Mono
mode,
the
LEFT
RCA
cable
connects
to
A+
input,
the
RIGHT
RCA
cable
connects
to
B-
input.
Remember
to
insert
the
RCA
Shorting
Plugs
in
the
unused
inputs.
The
speaker
outputs
connect
to
the
speaker
as
follows:
A+
output
connects
to
the
Positive(+)
speaker
terminal;
B+
output
connects
to
the
Negative(-)
speaker
terminal
(see
Fig.
3).
ADCOM
car
audio
amplifiers
are
stable
driving
a
1
Ohm
mono
load,
but
it
is
not
recommended.
For
best
results
(maximum
SPL
and
low
THD),
we
suggest
a
2
or
4
Ohm
mono
load.
BE
CERTAIN
OF
POWER/GROUND
CONNECTIONS
Fig. 3

in the MoSt™ configuration, the amplifier is capable of driving multiple
pairs
of
stereo
speakers
(properly
crossed-over),
and
multiple
mono
subwoofers, simultaneously!
To wire the MoSt™ configuration, connect the LEFT RCA to the A+
input; connect the RIGHT RCA to the B- input Remember to insert the RCA
Shorting Plugs in the unused inputs. Wire speakers as shown in Fig. 4.
LEFT
Shorting
esas)
Í Since you are |
~ i inverting the |
i | input on “B” or |
i RIGHT channel
: You invert the
“B” or RIGHT
i channel output,
i as well.
SUBWOOFER
BE CERTAIN OF POWER/GROUND CONNECTIONS
Fig. 4