Adcom GFA-5500 User manual

AXXM
details you can hear
G FA-5500
High Current
Power Amplifier
OWNER’S MANUAL

THE FOLLOWING PRECAUTIONS AND SAFETY INSTRUCTIONS
ARE REQUIREMENTS OF UL AND CSA SAFETY REGULATIONS
Warning: To reduce the risk of fire or electric shock, do not expose
this unit to rain or moisture.
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
AVIS: RISQUE DE CHOC ELECTRIQUE-NE PAS OUVRIR,
The graphic symbol of a lightning flash with an arrow
point within a triangle signifies that there is dangerous
voltage within the unit and it poses a hazard to anyone
removing the cover to gain access to the interior of the
unit.Only qualified service personnel should make
any such attempt.
The graphic symbol of an exclamation point within an
equilateral triangle warns a user of the device that it is
necessary to refer to the instruction manual and its
warnings for proper operation of the unit.
Do not place this unit on an unstable cart, stand, tripod,
bracket, or table. The unit may fall, causing serious
injury to a child or adult, and serious damage to the
unit. Use only with a cart, stand, tripod, bracket, or table
recommended by the manufacturer, or sold with the
unit. Any mounting of the device should follow the man¬
ufacturer's instructions, and should use a mounting ac¬
cessory recommended by the manufacturer.
Read all the safety and operating instructions before connecting or using
this unit.
Retain this notice and the owner’s manual for future reference.
All warnings on the unit and in its operating instructions should be adhered to.
All operating and use instructions should be followed.
Do not use this unit near water: for example, near a bathtub, washbowl,
kitchen sink, laundry tub, in a wet basement, or near a swimming pool.
The unit should be installed so that its location or position does not interfere
with its proper ventilation. For example, it should not be situated on a bed,
sofa, rug, or similar surface that may block the ventilation openings; or
placed in a built-in installation, such as bookcase or cabinet, that may
impede the flow of air through its ventilation openings.
The unit should be situated away from heat sources such as radiators, heat
registers, stoves, or other devices (including amplifiers) that produce heat.
The unit should be connected to a power-supply outlet only of the voltage
and frequency marked on its rear panel.
The power-supply cord should be routed so that it is not likely to be walked
on or pinched, especially near the plug, convenience receptacles, or where
the cord exits from the unit.
Clean unit only as recommended in its instruction manual.
The power-supply cord of the unit should be unplugged from the wall outlet
when it is to be unused for a long period of time.
Care should be taken so that objects do not fall, and liquids are not spilled,
into the enclosure through any openings.
This unit should be serviced by qualified service personnel when:
A. The power cord or the plug has been damaged; or
B. Objects have fallen, or liquid has been spilled, into the unit: or
C. The unit has been exposed to rain, or liquids of any kind; or
D. The unit does not appear to operate normally, or exhibits a
marked change in performance: or
E. The device has been dropped, or the enclosure damaged.
DO NOT ATTEMPT SERVICING OF THIS UNIT YOURSELF.
REFER SERVICING TO QUALIFIED SERVICE PERSONNEL
ATTENTION
POUR PREVENIR LES CHOCS ELECTRIQUES NE PAS UTILISER
CETTE FICHE POLARISEE AVEC UN PROLONGATEUR, UNE PRISE
DE COURANT OU UNE AUTRE SORTIE DE COURANT, SAUF SI LES
LAMES PEUVENT ETRE INSEREES A FOND SANS EN LAISSER AU-
CUNE PARTIE A DECOUVERT.
CAUTION
TO PREVENT ELECTRIC SHOCK DO NOT USE THIS POLARIZED PLUG
WITH AN EXTENSION CORD, RECEPTACLE OR OTHER OUTLET UN¬
LESS THE BLADES CAN BE FULLY INSERTED TO PREVENT BLADE
EXPOSURE.
CAUTION
POWER LINES
Any outdoor antenna must be located away from all power lines.
OUTDOOR ANTENNA GROUNDING
If an outside antenna is connected to your tuner or tuner-preamplifier, be
sure the antenna system is grounded so as to provide some protection
against voltage surges and built-up static charges. Section 810 of the
National Electrical Code, ANSI/NFPA No. 70-1984, provides information with
respect to proper grounding of the mast and supporting structure, grounding
of the lead-in wire to an antenna discharge unit, size of grounding
conductors, location of antenna discharge unit, connection to grounding
electrodes, and requirements for the grounding electrode.
a. Use No.10 AWG (5.3 mm^) copper, No.8 AWG (8.4 mm^) aluminum,
No.17 AWG (1.0 mm") copper-clad steel or bronze wire, or larger, as a
ground wire.
b. Secure antenna lead-in and ground wires to house with stand-off
insulators spaced from 4-6 feet (1.22-1.83 m) apart.
c. Mount antenna discharge unit as close as possible to where lead-in
enters house.
d. Use jumper wire not smaller than No.6 AWG (13.3 mm") copper, or the
equivalent, when a separate antenna-grounding electrode Is used. See NEC
Section 810-21 (j).
EXAMPLE OF ANTENNA GROUNDING AS PER NATIONAL ELECTRICAL CODE INSTRUCTIONS
CONTAINED IN ARTICLE 810 - RADIO AND TELEVISION EQUIPMENT.
NOTE TO CATV SYSTEM INSTALLER
This reminder is provided to call the CATV system installers attention to
Article 820-22 of the National Electrical Code that provides guidelines for
proper grounding and, in particular, specifies that the cable ground shall be
connected to the grounding system of the building, as close to the point of
cable entry as practical.

INTRODUCTION
Congratulations on your decision to purchase the GFA-5500 Stereo Power Amplifier. You have made a wise choice that
will reward you with exceptionally accurate and musical sound reproduction for years to come. To realize the full
potential of your new amplifier, please read these operating and installation instructions thoroughly before attempting to
connect it. Furthermore, it is a good idea to keep this manual handy for future reference.
FEATURES
• Precision matched MOSFETs used throughout the signal path.
• 80,000 pF of power supply filter capacitance with low ESR for greater reserve capacity.
• Low number of gain stages improves signal reproduction accuracy.
• Custom toroidal power transformer provides better regulation and greater peak current capability.
• High quality, gold plated binding posts.
• Independent thermal overload and distortion LEDs for each channel.
• Gold plated, brass RCA jacks with Teflon insulators.
• Large, exposed heatsinks for greater cooling capability of output devices.
• Heavy gauge, anodized aluminum front panel.
• Powder coated, baked chassis and top cover for greater durability.
• Increased cooling vents on top cover for greater efficiency and cooler operation while driving low impedance loads.
IMPORTANT NOTICE
ADCOM PROTECTION PLAN
(USA ONLY)
ADCOM offers the enclosed valuable Limited Warranty. Please read the details on the Warranty Card carefully to
understand the extent of the protection offered by the Warranty, its reasonable limitations, and what you should do in
order to obtain its benefits.
Be sure to verify that the serial number printed on the rear panel matches the serial number on the outer carton. If
any number is altered or missing, or if the ADCOM Warranty Card is not included in the carton, you should notify us
immediately in order to ensure that you have received a genuine ADCOM product which has not been opened,
mishandled, or tampered with in any way.
1

UNPACKING
Before your new GFA-5500 left our factory, it was carefully inspected for physical imperfections and tested for all
electrical parameters as a routine part of ACCOM's systematic quality control. This, along with full operational and
mechanical testing, should ensure a product flawless in both appearance and performance. After you have unpacked the
GFA-5500 inspect it for physical damage. Save the shipping carton and all packing material as they are intended to
reduce the possibility of transportation damage, should the amplifier ever need to be shipped again. In the unlikely event
damage has occurred, notify your dealer immediately and request the name of the carrier so a written claim to cover
shipping damages can be initiated
THE RIGHT TO A CLAIM AGAINST A PUBLIC CARRIER CAN BE FORFEITED IF THE CARRIER IS NOT NOTIFIED
PROMPTLY IN WRITING AND IF THE SHIPPING CARTON AND PACKING MATERIALS ARE NOT AVAILABLE FOR
INSPECTION BY THE CARRIER. SAVE ALL PACKING MATERIALS UNTIL THE CLAIM HAS BEEN SETTLED.
INSTALLING THE GFA-5500
During normal home operation the external heatsinks of the GFA-5500 will become warm. However, there are instances
during high-level playback into low impedances when the heatsinks will become much warmer than usual. To ensure the
amplifier’s long-term, trouble-free operation it is necessary to provide adequate ventilation for the heatsinks. Therefore,
the GFA-5500 should be kept away from external sources of heat such as radiators and hot-air ducts. The GFA-5500
should never be placed with other heat-producing components in a cabinet or enclosure lacking free air flow.
If you require that the GFA-5500 be mounted in an enclosed cabinet, it is recommended that the rear panel of the cabinet
be provided with ventilation openings at the top and bottom to allow air to circulate freely in the cabinet. The top and
bottom panel of the amplifier's chassis have been provided with vents to allow the necessary cooling of the internal
components. It is imperative that these vents are not obstructed in any way.
We recommend that you do not stack other components on top of the GFA-5500. This is particularly important If your
system includes low-impedance loudspeakers which are difficult to drive, or if you will consistently demand high volume
levels from the amplifier and speaker system. Not only will heat generated by the amplifier affect the performance of
equipment stacked on top of the GFA-5500, but the free flow of air through the ventilating slots in the amplifier may be
partially obstructed.
If you observe these recommendations, the GFA-5500 will perform reliably in any reasonable environment. You should
also pay attention to such normal considerations as protection from excessive dust and moisture. Occasional vacuuming
of accumulated dust on the chassis, heatsinks, panels and around the ventilating slots should be all that is required.
The optimal performance of your new GFA-5500 will ultimately depend on the care with which you make the connections
between the amplifier, preamplifier and the loudspeakers. All input and output signal connections should be made only
with high quality, low-loss, low capacitance cables following the recommendations in the following relevant sections.
Please refer to the rear panel diagram to identify all the connector locations.
WARNING
DO NOT EXPOSE THE AMPLIFIER TO RAIN, WATER, OR MOISTURE OF ANY KIND.
RIGHT/LEFT INPUT (D
The audio inputs to the GFA-5500 are through two high quality, gold plated RCA jacks to minimize high frequency losses,
noise, etc. They will accept standard RCA type plugs, one for each channel, LEFT and RIGHT, usually supplied at the
ends of interconnecting cables. To ensure that the performance designed into the GFA-5500 is realized, you should use
the highest quality cables feasible. There are many cables which are designed specifically for these applications and
your ADCOM dealer can be of help in selecting the best cable for your application. Whatever cable you finally select, it
should have low capacitance. This is particularly important if you use a long run between the preamplifier and amplifier.
Generally speaking, a cable with a capacitance of less than 100 pF will work best
The load impedance which the GFA-5500 inputs present to the source preamplifier or tuner-preamplifier is 49.9k ohms.
This load impedance results in minimal amplifier noise when used with a source component of low output impedance
such as an ADCOM preamplifier or tuner/preamplifier.
To preserve the correct stereophonic effects, please be certain to connect the left output of the preamplifier or tuner-
preamplifier to the RCA jack on the GFA-5500 labeled LEFT INPUT and the right output of the source component to the
RIGHT INPUT jack.
2

GFA-5500 Rear Panel Diagram
WARNING
WHENEVER CONNECTIONS TO OR FROM THE GFA-5500 ARE BEING MADE, BE CERTAIN THAT THE
AC ON/OFF SWITCH OF THE AMPLIFIER IS IN THE OFF POSITION. THE AC CORD OF THE AMPLIFIER
IS DISCONNECTED FROM THE AC WALL OUTLET AND THAT ALL ASSOCIATED COMPONENTS ARE
OFF.
RIGHT/LEFT OUTPUT (D
The GFA-5500's connection to the loudspeakers are made through two high quality, five-way, gold plated binding posts
located on the rear panel. These terminals will accommodate either bare wire, tinned wire, terminal pins, spade lugs or
banana plugs, both single and dual. These output terminals are color coded RED and BLACK to indicate polarity. To
ensure correct stereo phasing, you must connect the RED output terminal (labeled “+") to the loudspeaker input terminal
color coded RED (or labeled POSITIVE, POS, 8 OHMS or 4 OHMS). The BLACK binding post terminal on the
amplifier (labeled should be connected to the loudspeaker input terminal color coded BLACK (or labeled NEGATIVE,
NEC. C, COMMON, G. or GROUND).
The RIGHT OUTPUT should be connected to the right channel loudspeaker, as you face the pair of loudspeakers, and
the LEFT OUTPUT to the left channel loudspeaker.
In order to ensure that connections to the loudspeakers are correct, you must be able to identify each wire conductor of
the loudspeaker cables at both ends of the cables. This is relatively easy to do since most loudspeaker cables'consist of
two parallel, stranded conductors in a flexible insulation, with a coding system for wire identification. Sometimes there is
a colored “tracer" wrapped around one of the conductors; some cables have one of the conductors colored silver and the
other copper; some have a “ridge" molded on the insulation of one of the conductors, while others are imprinted with *+"
and/or markings. Your ADCOM dealer also sells special loudspeaker cables and these are most often labeled with
respect to polarity.
3

NOTE
THE GFA-5500 IS POLARITY CORRECT AND DOES NOT INVERT PHASE, THAT IS, ANY POSITIVE GOING
SIGNAL AT ITS INPUT WILL APPEAR AS A POSITIVE GOING SIGNAL AT ITS OUTPUT,
Generally speaking, when making connections to the loudspeakers from the amplifier it is very important to use the
correct type and size of wire in order to avoid unnecessary loss of amplifier power in the cable, reduction of amplifier
damping factor and other undesirable conditions. For runs up to twelve feet, ordinary “zip” or lamp cord, made up of
AWG18 stranded wire and available in a variety of insulation colors may be used. For runs up to forty feet, AWG16
stranded wire should be used as a minimum to prevent power losses. For lengths over forty feet and not exceeding sixty
feel, use at least AWG14 stranded wire. Runs exceeding sixty feet require the use of heavier conductors such as
AWG12,
Regardless of the cables you select to connect your loudspeakers, there are some additional requirements which you
should observe in order to ensure maximum performance from your amplifier. It is most important that you make certain
the wiring you have selected has as low a capacitance as possible. All amplifiers, particularly wide bandwidth audio
amplifiers are susceptible to the capacitance cables present to their outputs at extremely high frequencies. This
capacitance, in conjunction with the inductance of the wire itself and the reactive load of the loudspeakers, can create
anomalies at ultrasonic frequencies which, although inaudible, can affect performance in the audible range.
There are several different ways to connect the wiring to the RIGHT and LEFT OUTPUTS, The methods used will
depend on the specific type of connectors supplied with the loudspeakers, the speaker cables, etc. As a matter of
course, we prefer to use banana plugs because it is generally the most secure method of connection. Also, the springs
of the banana plugs create a self-cleaning action which ensures the best contact between the binding posts and the
connectors themselves. There are “sockets” provided in the center of the binding posts’ studs which permit secure
seating of the banana plugs. Before inserting the banana plug into the binding post, ensure the binding post is securely
hand tightened in a clockwise direction.
Additionally, when connecting the cables to the amplifier and loudspeakers, it is important that you “tin” the wires with
good quality electronic solder in order to minimize contact resistance. Tinning prevents the buildup of surface
compounds which can form on copper wire and increase its contact resistance. It is partly for this reason that banana
plugs are preferred. However, make sure that the cable ends are tinned before you make the cable connections to the
banana plugs. Alternatively, you can use “crimped” pins or other lugs to ensure low contact resistance at the connection
to the amplifier and loudspeakers.
If you prefer to use other methods of connection, unscrew the insulated head of the binding post until the hole in the
binding post stud is accessible. You can then insert the bare or tinned wire, or terminal pin, through the hole. You can
also use the many variety of spade lugs available by simply placing the tines of the spade lug onto the binding post stud.
Turn the insulated head of the binding post clockwise until the wire or connector is firmly secured. Finger pressure is
sufficient and you should not use pliers or other tools which could damage or over tighten the binding post assembly.
The binding post has been designed in such a way that finger pressure is all that is required to cause a “pinching” action
among the different metal surfaces to ensure proper connection.
All loudspeakers having a nominal impedance down to 4 ohms can be connected to, and driven by the GFA-5500, The
amplifier can drive these low impedances at more than adequate power levels with no difficulty. It should be noted here
that many loudspeaker systems which are nominally rated at 4 ohms drop in impedance, in some parts of their frequency
range, to as low as 2 ohms (and some others to even less than 2 ohms). You will not experience difficulties even with
these very low impedance loads unless you demand excessively high volume levels from the system.
In most applications, you can drive two or more sets of loudspeakers. You should note, however, that when
loudspeakers are paralleled, the impedance presented to the amplifier is lower than the nominal impedance of each
loudspeaker. In other words, if you parallel two 8 ohm sets of loudspeakers, the resultant impedance presented to the
amplifier will be 4 ohms. If 8 ohm and 4 ohm loudspeakers are paralleled, the resultant impedance will be approximately
2,6 ohms. In this last situation, depending upon the lowest impedance of the nominally 4 ohm speakers, and if excessive
power demands are placed on the amplifier, you may trigger the THERMAL PROTECTION on the amplifier or blow one of
the EXTERNAL PROTECTION FUSES, See its respective section for more information. For convenient switching of
multiple sets of speakers with impedance protection for the amplifier, you should consider the use Of an ADCOM speaker
selector. These are available from your local ADCOM dealer.
4

AC LINE CORD (T)
NOTE
The GFA-5500’s power cord is supplied with a "polarized" AC plug as required bv UL/CSA stanri;,rH^ =,nH fho
i r,"if «^«ncal Shock and to?n ™ re mlnlji;? h i frSm [?!
etedric^s'hS-k^H ‘’“T"’' P'“9 (“hP «*«e “afe and one narrow blade) To prevent
foil, ihserSl prevent b"Setp’’ot^^^^^^^ ""
AC POWER FUSE ®
^o^rXrl"g'^o';?he not c^V^tLe the amplifier is energized, the POWER LED will
blown Unpluq the AC LINE CORn fmm Ar n ‘he AC POWER FUSE is
vt WARNING
U«PbUO TH. *C
Exf rr^ K^hXrrXr £
cap in the fuse holder body should be easily accomplished without excessive force THREADS. Seating of the
„ , , WARNING
SffERe“;^^^^^^ USE SUBST^TUTfFUSEl"vJ?S
Circuits, MAY CREATE A FIRE Ha'^R^AND MA^wfc ?h^
AC POWER FUSE For 115 Volt operation: 12 AMP ABC/250V
_ POWER FUSE For 230 Volt operation: 6 AMP ABC/250V
AC ON/OFF SWITCH ©
5

POWER LED 0
This LED will glow whenever the AC ON/OFF switch is turned on and the GFA-5500 is energized. If the AC LINE FUSE
blows the POWER LED will cease to glow.
The POWER LED indicates that there is AC voltage being fed to the amplifier, but it does not signify that all the
amplifier's circuits are in operation. If, for example, you have blown one or more of the EXTERNAL PROTECTION
FUSES, the amplifier will not operate. That is, the amplifier will not produce any audio signal even though the POWER
LED is glowing. Similarly, if the THERMAL PROTECTION LED glows, the amplifier will not produce sound even though
the POWER LED may still glow.
Additionally, the internal power transformer is provided with a thermostat which will interrupt power into the transformer if
its temperature exceeds 125°C. This high temperature will seldom, if ever, be encountered unless the amplifier is
subjected to abnormal conditions, such as operation into loads of less than 3 ohms at very high listening levels, etc. If
the AC POWER FUSE is not blown, the POWER LED is out, the THERMAL PROTECTION LED is out and the
EXTERNAL PROTECTION FUSES are intact, this would indicate that the thermostat within the transformer has opened.
Once the temperature within the transformer decreases to a normal level, the thermostat will reset itself automatically and
normal operation will resume. If you are to avoid continually tripping the thermostat in the transformer, you must reduce
the sound level demands, correct the load impedance of the loudspeakers, or both.
INSTANTANEOUS DISTORTION ALERT LEDs ®
The INSTANTANEOUS DISTORTION ALERT circuit is a unique ADCOM distortion detection system which reads all
forms of non-linear distortion such as THD, IM, slew-induced, “clipping”, etc. The INSTANTANEOUS DISTORTION
ALERT LEDs will light when distortion reaches 1% regardless of impedance, voltage/current phase angle or the
reactance of the loudspeakers which the amplifier is driving. Sometimes, when the amplifier is in use, the LEDs may
occasionally flicker during high volume listening, particularly if you are driving low impedances. This flickering is no
cause for concern. The LEDs are simply warning you that the amplifier is approaching its maximum power output into the
particular loudspeakers you are using. If, however, the INSTANTANEOUS DISTORTION ALERT LEDs glow brightly or
are illuminated most of the time during playback, you are overdriving the amplifier and should turn down your volume
control to reduce the listening level or you may blow one or more of the EXTERNAL PROTECTION FUSES, cause the
THERMAL PROTECTION to be activated or, in extreme cases, damage your loudspeakers.
GFA-5500 Front Panel Diagram
6

THERMAL PROTECTION LEDs (S
The GFA-5500 is provided with a thermal protection circuit which will shut down the amplifier if either heatsink's
temperature reaches 85”C. The THERMAL PROTECTION LEDs will light Whenever the thermal prWL^on drcufon its
tnggered and the amplifier is inoperative. The thermal protection circuitry will typically be
eSSs f demands into impedances much lower than the amplifier is capable o7drivin^at thoL
p „ channel s output through the loudspeaker(s) ceases abruptly, and one or both the THERMAL
h ^ ‘'^^t its heatsink temperature has become unacceptably high and the circuitry is
eneS n note that the POWER LED will remain on and the amplifirwTlI st^be
resume oper?t"oa heatsink(s) drops to a safe operating level, the amplifier will automatically
NOTE
ACTIVATION OF THE THERMAL PROTECTION CIRCUITRY IN THE GFA-5500 IS AN INOICATinM tuat tuiit
AMPLIFIER HAS BEEN OVERDRIVEN OR THAT THE LOAD THE LOUDSPEAKERS ARE PRESENTING TO THP
AMPLIFIER IS UNREASONABLY LOW. IF YOU WISH TO PREVENT
CIRCUITRY. YOU MUST REDUCE THE VOLUME LEVEL DEMANDS OR CORRECT
THE LOAD-IMPEDANCE CONDITION WHICH MAY BE CAUSING ACTIVATION OF THIS CIRCUITRY, OR BOTH
EXTERNAL PROTECTION FUSES (D
There is an additional protection provided to the GFA-5500 in the form of EXTERNAL PROTECTION FUSES for thP nr
are rnade of me ampKeV e«heMoa f^m or
Short term, and are meant to protect not only the loudspeakers, but the power output devices as well. ^
If the amplifier ceases to operate from either one or both channels, particularly during high level passaaes or Iona tPrm
high volume playback, and the POWER LED glows while the THERMAL PROTFotiom i pi^o ^ ^
one or more of the EXTERNAL PROTECTION FUSES are blLn PROTECTION LEDs are out, chances, are that
Your GFA-5500 is designed to activate its protection devices reliably, particularly when the amolifier is rareipsdu
-®<^ a^P'-«er usuallj
WARNING
SUBSTITUTE
serious damage to the amplifier circuits, MAY CREATE A FIRE HAZARD, AND MAY VOID THE WARRANTY^
_EXTERNAL PROTECTION FUSE VALUE/TYPE: 8 AMP AGC/250 VOLT
WARNING
THERE ARE POTENTIALLY LETHAL VOLTAGES WITHIN THE GFA-5500 AMPLIFIFR RFMnx/iwr tuc
COVER GREATLY INCREASES YOUR CHANCE OF INADVERTENTLY EXPOSING YOURSFI F TO^FXTRpmp
DANGER. REFER ALL SERVICING TO QUALIFIED, ADCOM AUTHORIZED no hot
ATTEMPT TO SERVICE, REPLACE, OR REPAIR ANY INTERNAL COMPONENT YOURSELF.
7

CARING FOR YOUR GFA-5500
Great care has been taken by ADCOM to ensure that your amplifier Is as flawless In appearance as it is eiectronically. The
front panel is a heavy gauge, high-grade aluminum extrusion carefully finished and anodized for durability. The chassis, top
cover and rear panels are heavy gauge steel, that has been powder coated and baked to ensure a lasting finish. If the front
panel, top or sides become dusty or finger printed, they can be cleaned with a soft lint free cloth, slightly dampened with a very
mild detergent solution or glass cleaner.
WARNING!
Do not spray or pour liquids of any kind on the GFA-5500
SERVICING
ADCOM has a Technical Service Department to answer questions pertinent to the installation and operation of your unit. In
the event of difficulty, please contact us for prompt advice. If your problem cannot be resolved through our combined efforts,
we may refer you to an authorized repair agency, or authorize return of the unit to our factory. To aid us in directing you to a
convenient service center, it would be helpful if you indicate which major city is accessible to your home.
Please address mail inquires to; Phone, Fax or E-mail inquires to:
ADCOM Service Corporation Tel.: [phone]
10 Timber Lane Fax; 732-683-9790
Marlboro, NJ 07746 USA Monday through Friday
9:00 AM to 5:00 PM EST
E-Mail: [email protected]
For Fax inquires, please include a return Fax number for the reply. When calling or writing about your GFA-5500, be sure to
note and refer to its serial number as well as the date of purchase and the dealer from whom it was purchased. It is helpful in
any communications to us, please include a daytime phone number where we may reach you. In the event the unit must be
returned to our factory for service, you will be instructed on the proper procedure when you cail or write for a Return
Authorization. UNDER NO CIRCUMSTANCES SHOULD YOUR UNIT BE SHIPPED TO OUR FACTORY WITHOUT PRIOR
AUTHORIZATION, OR PACKED IN OTHER THAN ITS ORIGINAL CARTON AND FILLERS.
if the original shipping carton and its fillers have been lost, discarded, or damaged, a duplicate carton may be
obtained from our Service Department for a nominal charge.
Always ship PREPAID VIA UNITED PARCEL SERVICE (UPS) OR OTHER APPROVED CARRIER. DO NOT SHIP
VIA PARCEL POST, since the packing was not designed to withstand rough Parcel Post handling.
FREIGHT COLLECT SHIPMENTS WILL NOT BE ACCEPTED
UNDER ANY CIRCUMSTANCES.
8

GFA-5500 SPECIFICATIONS
Power Rating (To FTC Requirements)
200 Watts continuous average power Into 8 ohms at any frequency between 20Hz and 20kHz with both channels
driven at less than 0.18% THD.
350 Watts continuous average power into 4 ohms at any frequency between 20Hz and 20kHz with both channels
driven at less than 0.18% THD.
IM Distortion (SMPTE)
1 watt to 200 watts into 8 ohms.
1 watt to 350 watts into 4 ohms.
< 0.05%
< 0.05%
IM Distortion (CCiF, Any Combination from 4kHz to 20KHz)
200 watts Into 8 ohms.
350 watts into 4 ohms.
^ 0.035%
< 0.035%
THD + Noise at 200 watts into 8 Ohms (Typicai)
20Hz.
1 kHz.
10kHz.
20kHz.
.0.018%
0 . 0 20 %
0.070%
0.130%
THD + Noise at 350 watts into 4 Ohms (Typicai)
2OH2 .
.0.018%
1kH7 .
.0.020%
inn-i-7 .
.0.080%
Frequency Response @ 1 Watt Into 8 Ohms
10Hz to 20kHz.
Power Bandwidth (-3dB).
Dynamic Headroom into 4 Ohms.
Signal to Noise Ratio, “A” Weighted
200 watts into 8 ohms.
Gain.
Input Impedance.
Damping Factor
20Hz to 20kHz.
.+0, -0.25dB
3Hz to 130kHz
.1.7dB
.> lOOdB
.29dB
.49.9k ohms
.> 700
Rise Time
5kHz, 120V peak-to-peak square wave, 20% to 80%.
Power Consumption (Continuous, Both Channels Driven)
Quiescent.
Maximum..
200 watts into 8 ohms.
350 watts into 4 ohms.
I.SpS
..192VA
1440VA
. .660VA
.1165VA
GENERAL
Power (available in 230V by special order)
Chassis Dimensions.
Maximum Dimensions.
Weight.
Weight, Packed.
.115VAC-50/60HZ
. 7" (178mm) x 17" (432mm) x 13y4" (349mm)
I'A" (184mm) x 17" (432mm) x 14%" (375mm)
.44 lbs. (20kg)
.50 lbs. (23kg)
9

>CCOM
10 Timber Lane
Marlboro, NJ
07746 USA
Tel: [phone]
Fax: [phone]
www.adcom.com
Printed in the USA
GFA55/98/V.1.2