Adcom GFA-4304 User Manual

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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. Ail rights reserved. ©1994 ADCOM Inc.

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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 Deaier! Please refer to your warranty card

for further details.

GFA-4302

GFA-4402

Power Output 30 W/Ch @ 40 W/Ch @ 30 W/Ch @

4 Ohms Stereo

Power Output 60 W/Ch. @

<0.1% THD*

<0.1% THD*

80 W/Ch. @

2 Ohms stereo <0.25% THD* <0.25% THD*

Power Output

4 Ohms Mono

100 Watts® 140Watts @ 110Watts @

<0.25% THD* <0.25% THD* <0.25% THD*

Frequency OHz-SOKHz 0HZ-50KHZ OHz-SOKHz

Response

Power

Bandwidth +0dB, -3dB

+0dB. -3dB +0dB. -3dB

0HZ-50KHZ

OHz-bOKHz

+0dB, -3dB +0dB, -3dB

Input Impedance 8.5 K Ohms 8.5 K Ohms

GFA-4304 GFA-4404 GFA-4702

40 W/Ch @ 70 W/Ch @
<0.1% THD* <0.1% THD* <0.1% THD*
60 W/Ch. @

<0.25% THD*

+0dB, -3dB

OHZ-bOKHZ 0HZ-50KHZ

8.5 K Ohms

80 W/Ch. @ 140W/Ch. @

<0.25% THD*

150Watts@

<0.25% THD*

OHz-SOKHz

+0dB, -3dB

+0dB. -3dB +0dB, -3dB

8.5 K Ohms

<0.2% THD*

250Watts @

<0.2% THD*

0HZ-50KHZ

+0dB, -3dB

OHZ-50KHZ

8.5 K Ohms

Input Sensitivity 400mV to 2V 400mV to 2V 400mV to 2V 400mV to 2V 600mV to 2V

Separation

>90 dB

S/N Ratio ^100 dB ^lOOdB

Damping Factor

350

Idle Current 3 Amps

Fuse size

Weight

20 Amp

8 lbs (3.7kg)

Dimensions 9.75x10.75x2.3" 9.75x12.75x2.3"

in Inches WxLxH

' THD Ratings measured between 20Hz and 20khz

>90 dB >90 dB >90 dB >90 dB

>100 dB >100 dB

600 600

9 Amps 10 Amps
50/Vnp

9.75x24.25x2.3"

32 lbs (14.6kg)

9.75x24.25x2.3"

600
3 Amps
30 /Vnp

10 lbs (4.6kg)

WxLxH

>100 dB

350

6 Amps

50 /Vrip

12 lbs (5.5kg) 19 lbs (8.7kg)

9.75x14.75x2.3"
WxUH WxLxH 9.75x15.5x2.3"

50 Amp

HOW TO USE THIS MANUAL

This manual is divided into three distinct sections:

Section 1: Common features, instructions and connections fora//

ACCOM 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 ACCOM 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

1 Amplifier

1 Owner’s Manual

1 Warranty Card

1 In Line Fuse Holder

2 RCA Shorting Plugs

GFA-4702 (Amp Section)

1 Amplifier Section

1 Owner’s manual

1 GFY-4 XLR/RCA Adapter

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 should contact ADCOM immediately at (908) 390-1130.

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 ACCOM’s Quality Assurance system. This is to ensure flawless performance

and appearance when you receive it.

GFA-4304 and GFA-4404

1 Amplifier

1 Owner’s Manual

1 Warranty Card

1 In Line Fuse Holder

2 GFY-4 XLR/RCA Adapters

GFA-4702 (Power Supply)

1 Power Supply Section

1 Warranty Card

1 GFC-1 Power Cable

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 PROM PTLY AND IF THE SHIPPING CARTON AND

PACKING MATERIAL ARE NOT AVAILABLE FOR INSPECTION. SAVE

ALL PACKING MATERIAL UNTIL THE CLAIM HAS BEEN SETTLED.
MOUNTING:

All 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 downi

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 -4|||||||^

CONNECTING POWER:

ACCOM 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 6AWG wire. 8AWG cable 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

8AWG 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 amplifter! When a fuse blows, replace ONLY with an identical

amperage fusel

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 SPOT 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

Ground 86 ~ 30

distribution block)

Fig. 1

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 '/a Q, continuous operation into impedances lower than 2 i2 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 ail system components.

MoStTM CONFIGURATION:

ADCOM Car Audio amplifiers are capable of running stereo and mono

configurations simultaneously. In order to achieve this, one channel must be

inverted af 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 vi^hen sensitivity controls are turned fully

clockwise. Since the sensitivity controls affect only the positive inputs, the

controls MUST be fully clockwise in the MoSt™ or mono configurations.

CARE AND CLEANING:

Great care has been taken by ADCOM to assure that your amplifier is

as ftavriess in appearance as it is electrically, in the event that your ACCOM

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 ampiifier,

please contact your local authorized dealer or call ADCOM Customer Service at

(908) 390-1130 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 to 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 ampiifiers. For stereo

operation. RCAs connect to the left-most input jacks, labeled A-t- and B-i-. When

using the ampiifier in either a bridged Mono or MoSt™ configuration, the upper

left and lower right inputs, labeled A+ and 6-, 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 Storoo 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