Adcom GFA-555MS manual Introduction, Preface

Page 2

INTRODUCTION

 

 

 

Pleasereadthoroughlytheseoperatinginstructions

fortheGFA555msbeforeconnecting

orattemptingtooperateit.Theinstallationando

perationoftheGFA555msaredescribedin

thefollowingpages.Wesincerelyhopeyouwillval

ueandenjoytheconsiderableattention

we have given its design and construction. This man

ual has been written to help you

understand the correct operation of the GFA555ms.

Please read it carefully to fully

comprehendallitsfeaturesandfunctionsandthere

byderivemaximumperformancefromits

useinyoursystem.Itisagoodideatokeepthis

manualhandyforfuturereference.

PREFACE

 

 

 

 

 

 

WARNING

 

 

TheGFA555msisaverypowerfulamplifiercapable

 

ofdeliveringverylargepeaksintolow

impedances, exceeding 80 amperes per channel. There

fore, be certain to exercise

extreme cautionwhenmakingconnectionstoandfromtheamp

lifier. Always make certain

that the amplifier is disconnected from the AC outlet, and its large filter capacitors

are discharged. Pleasenotethatthepowersupplycapacitorscanta kemorethan five

minutes todischarge . Failure to observe this precaution may result in damage to the loudspeakers and/or blowing of the amplifier's DC RAIL FUSES, conditions which are NOT covered by the warranty.

TheGFA555msamplifiercandriveaverybroadrang

eofloudspeakers. includingthose

withverylowimpedances,atsustainedhighpowerl

 

evels,evenwhentheimpedancesare

highlyreactive.Greatcarewastakentoinsuretha

 

tdistortionintheamplifierwouldremain

extremely low, particularly when driving these high

ly reactive loads in which the phase

anglesofthevoltageandthecurrentaresubstanti

 

allydifferent.Alittleknownfactisthat

amplifierswhichmeasureextremelywellonthetest

benchintoaresistiveloadmaynot

developthesameamountofpowerintoaloudspeaker

.Dependingontheamplifier'sdesign,

sometimesaslittleasonethirdofthepowerwhich

 

theamplifierdevelopsintoaresistoris

deliveredtoaspeakerload.Also,thedistortionl

evelmeasuredwhentheamplifierisdriving

aresistiveloadisdegraded.insomecasesquites

 

ubstantially,whendrivingtheloudspeaker.

Itis,however,verydifficulttomeasuretheperfo

rmanceofanamplifierintoaloudspeaker.

Onereasonwhythisinformationisnotwidelyknown

isbecauseduringsuchhighpower

tests, destruction of the loudspeaker is often the

result. In order to determine the

performance of the GFA555ms, ADCOM developed a "co

mputer model" of a "difficult"

loudspeakerload.Acomputermodel"mimics"therea

ctanceoftheverydifficultspeakerand

duplicatestheactualphaseanglesofthevoltagea

 

ndcurrentthroughouttheentireaudio

range. In this manner, highpower testing of amplif

ier parameters could be undertaken

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Contents High Current Power Amplifier Introduction PrefacePage Important Notice Adcomprotectionplan U.S.AONLY UnpackingPage RIGHT/LEFT Input RIGHT/LEFT Stereeo Speaker OutputsSTEREO/BRIDGEDMONOINPUT/OUTPUT Page Page STEREO/BRIDGED Mono INPUT/OUTPUT DC Rail Fuses DC Rail Fuses Bussman MAYTstereospeakeroutputs LittelfuseAC Line Cord AC Line FuseSOC CES612A Void Your WarrantyAC Line Fuses Bussman Do not USE ANY Substitute Fuses With Different RatingsAC ON/OFF Switch Power LEDAdcom Thermal Protection LEDADCOMUSA/J&BDISTRIBUTION ActivationofthethermalprotectioncircuitryintIndication Thattheamplifierhasbeenoverdriveno Rthattheload PHOENIX,AZ85078Page GFA-555ms Specifications Page General

GFA-555MS specifications

The Adcom GFA-555MS is a high-performance power amplifier that has established a reputation for its reliability and excellent sound quality. This amplifier, developed by Adcom, an American audio company known for producing high-quality audio components, is often sought after by audiophiles and professionals alike for its unique features and robust build.

One of the standout characteristics of the GFA-555MS is its impressive power output. With a continuous power rating of 200 watts per channel into 8 ohms, and even more when driving lower impedances, it provides ample power to drive a wide variety of speakers. This ensures that users can enjoy dynamic sound reproduction, whether they are listening to music at moderate volumes or cranking it up for a party.

The GFA-555MS is designed using a high-current, Class AB topology, which strikes a balance between efficiency and sound fidelity. This design allows for clean, detailed audio reproduction while minimizing distortion. The amplifier is renowned for its ability to handle complex musical passages and reproduce them faithfully, making it a favorite among music lovers who appreciate the nuances of their favorite recordings.

Another notable feature is its advanced thermal management system. The GFA-555MS is equipped with substantial heat sinks and a robust power supply that allows it to operate efficiently without overheating. This is particularly beneficial for sustained listening sessions or when driving demanding speaker loads.

In terms of connectivity, the GFA-555MS offers various input options, including RCA and XLR connections, making it versatile enough to integrate into a range of audio systems. This flexibility is complemented by its exceptional build quality, with a solid chassis that not only enhances durability but also minimizes vibrations that could interfere with sound quality.

The amplifier also includes additional features such as DC protection circuitry and a comprehensive output stage protection system. These safeguards help protect both the amplifier and the connected speakers from potential damage due to short circuits or overheating.

Overall, the Adcom GFA-555MS stands out in the realm of audio amplifiers. Its combination of power, sound quality, and advanced technologies make it a preferred choice for both casual listeners and serious audiophiles. Whether for home theater setups or music playback, the GFA-555MS delivers performance that is hard to match, making it a true classic in the audio world.