Adcom GFA-5275 User Manual

2-CHANNEL

BALANCED

AMPLIFIER

SYSTEM

OWNER’S MANUAL

IF YOU READ NOTHING ELSE,

PLEASE READ THIS PAGE:

<J> INSTALLATION ADVISORY: Be sure to connect

the POWER{+) and GROUND{~) correctlyll Amplifiers

that are incorrectly connected are not covered by the

warranty.

INSTALUTION ADVISORY: It is possible for

clipped strands of wire to eriter the amplifier through
the Free*Flow perforated sieOve. Be sure to dip wires
well away from the amplifier to avoid this possibility

<|> INSTALUTION ADVISORY: The GFI‘5200

Balanced Line driver needs to be pieced as close to
the source unit as possible. The complete "Balanced

Line System* will operate properly ONLY when the
GFl-5200 is installed correctly.

<5> OPERATION ADVISORY: Make sure the two

sensitivity controls on the amplifiers are set fully

clockwise. When matching the output of the source

unit with the input of the amplifier, adjust the level

controls on the GFP5200 instead of the amplifier.
<|> OPERATION ADVISORY: Even though Adcom

amplifiers are capable of ddving very low Impedances,

it is recommended that the conUguradon not be lower

than 10 stereo, or 2^ Mono. This will ensure that you

receive optimum power and control, lowest distortion
and greatest reliability.

<|> OPERATION ADVISORY: If you are using this

amplifier with a GFI-4600 crossover, then please see
the “Connecting the GFI-4600* section on page 8.

® 0(

AlNiyAL

Congratulations! Thank you for choosing ACCOM Car Audio components
for your mobile audio needs. Your ACCOM Car Audio Balanced Amplifier
System- uses superior engineering principles and the highest quality components
to providsra musical experience with clarity and dynamics never before achieved
in a vehicle.

PLEASE read this manual entirely before attempting to install this
system. Cue to the sophisticated nature of this equipment, we highly recommend
an authorized ACCOM Car Audio Ceaier perform the installation to achieve the

maximum performance from your mobile sound systemi Your warranty is
affected if you choose to install your ACCOM amplifier yourself. You will receive
all the benefits of the limited warranty only if the amplifier is professionally
Installed by an authorized ACCOM Car Audio Cealerl Please refer to your
warranty card for details.

. TABLE OF CONTENTS;

THE BALANCED CONCEPT

CARTON CONTENTS..................................................................... 2

UNPACKING.................................................................................

CARE AND CLEANING

FAN AND LED OPERATION

MOUNTING

The Amplifiers.......................................................................... 3

the Balanced Line Driver................................................................3

CONNECTiNG THE POWER

The Amplifiers............................................................................ 4

The Balanced Line Driver

INPUT SENSITIVITY SETTINGS.......................................................5

SPEAKER CONNECTIONS............................................................. 6

UNBALANCED OPERATION

CONNECTING THE SYSTEM

Connecting the GFI-4600 Crossover

Connecting Other Brands of Balanced Equipment
DIAGRAM 9: Multi-Amp system with a GFl-4600 and GFY-2B
DIAGRAM 10: Multi-Amp system with Dual GFI-4600’s

TROUBLESHOOTING.....................................................................11

SPECIFICATIONS...........................................................................12

ADAPTER CABLES.........................................................................13

SERVICING

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2

2

3

10

14

3

7
8

8

9

THE BALANCED CONCEPT;

The advantaoa of a batanced line system is simóle: Noise reduction. Any
noise that is induced into the signal path is automatically canceled at the Input of
the amplifier. Therefore, induced noise is no longer a problem or concern for car
audio installers. In order to have a ‘balanced* ayatem, you need 3 Items:

1: a Balanced Line Driver (GFI-S2Ó0).
2; a Balanced-type Cable (two pairs of RCA cables).
3: a Balanced Amplifier (GFA-5225.GFA-5250 or GFA-5275). ..

If we follow the signal from the source (CO. Tape deck), to the amp, we can

see exactly how a Balanced Line System works.

As the signal exits the source unlL H is converted to a balanced signal by
the GFI-5200. It is then transmitted through the cables (two pairs of RCA cables)
to the balanced amplifier. If, while the signal is being transmitted, H picks up.any
induced noise. It will travel with the orii^nal to the input of the amplifier.

The amplifier's differential input will ignore the noise that was added, and only

amplify the original signal.

CARTON CONTENTS:

The Adcom GFA-S225, 6FA-S2S0 and GPA-5275 amplifiers are shipped

from the factory with the GFI-5200 2-channei Balanced Une Driver.

Also included vdth your Balanced System is a fiise holder vrith an
appropriately sized fuse. For proper connection of the fuse, see the
CONNECTING POWER secfion. There should also be a Warranty Registration
card included. Fill this out and drop it in the mail; there is no postage needed.
Even though you send in-the Warrarity card, you should atways keep your
original sales receipt for proof of purchase date. '.

UNPACKING;

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 System leaves our fadlity in New Jersey, it is
carefully inspected for physical imperfections and electrical performance as a
routine part of ACCOM's Quafity Assurance system. This is to ensure flawless
performance- and appearance when you receive H.

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 RIGI^ TO CLAIM A(3AINST 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.

CARE AND CLEANING:

• Great care haa been taken by ACCOM to assure that your amplifier and line
driver are as flawless in appearance as they are electrically. In the .event that
your ACCOM components needs cleaning, use a damp doth or dry, soft bristled
paint brush. Co not use cteadng fluids of any kind, as damage to the finish may
result. Treat these products as pradskm instruments, and they will provide

you

with many years of musical en^yment

FAN AND LED OPERATION:

The thermostatically oontrolied fen wiU begin operation almost immediately
upon tum-on. it yrtti create an. air flow through tite heat sink. As tits temperature
of the heat'Sink rises, the ftin wU increase in veto<%. In the unlikely event that

the amplifier thermaOy shuts down, the fen wiil continue to operate, cooling the
heat sink. The ampWfer will fern it^ back on once the temperature drops into

normal operating range.

' Adcom amplifiers aU have LEO fedicatprs behind the fiee-fiow chassis vents

where they can easily be seen. On each aropBfier there is 1 green LEO on the
power supply side (on the same side ss the power connections), this represents
the power supply, and Z graan LEDs on the amplifier (same side as the RCA
connectors) side vritich repres«^ the 2 channels of amplification. Both amplifiers
have a red LEO on the power supply side which will only light if there is some
sort of problem. See the troubleshooting section in the rear of the manual to
determine the source of the problem.

MOUNTING:

The GFA-5225. GFA^2S0 and GFA^27S Amplifiers .. ..

Afi, components should be securely mounted, as they could become
airborne in the event of a collision; ssrfcMis injury could o^r. ADCOM Car Audio
amplifiers may be mounted almost anywhere; every model is fen-^rooled, so
mounting possibilities are limfisd only by your imagination. Follow these simple
guidelines to ensure long fife, oosmetic integrity and sonic dependability; 1.

Always securely rhount the component to a flat surfece using all mounting holes.

2. Never mount an audio component where loose objects can come in contact

with it, 3. Never mount an amplifief under a rug. mat or carpet Remember, the

better the ventilation, the cooler your amp will runi

When mounting, do not use the amplifier as a drilling template. Use as a
marking template, only. Whan mounting an amplifier, use only Pan-Head

screws, not beveled head, and DO NOT OVER-TiGHTENI

Pan

Haart

Seiww

Bavalad

Haad|

Scraw

The GFI«5200 Balanced Line Drtver

CRITICAL ALWAYS MOUNT THE BAIANCEO UNE DRIVER AS CLOSE

TO THE SOURCE UNIT AS POSSIBLE. In order to utilize the advantages of a
balanced line, the signal needs to be converted from unbalanced to balanced as
soon as possible. The size of the 6FI unit enables it to be easily mounted in or