correctstereo phasing with optimal bass response,

youmustobservetheseconnections

 

precisely.

 

 

 

 

 

 

 

 

Although the GFA555ms can generate a substantially

greater amount of power in the

 

bridged mono mode than when it is in its normal ste

 

reo mode, it requires the use of

 

 

 

 

 

 

 

 

loudspeakers the nominal impedance of which does no

 

t drop below 4 ohms. It is not

 

 

 

 

 

 

 

recommendedthattheGFA555msbeusedinthebridg

 

edmonomodeintoloudspeakers,or

 

multipleloudspeakerloads,whichdropinvaluesub

 

stantiallybelow4ohms.Otherwise,you

 

maytriggertheTHERMALPROTECTION0orblowoneof

 

theDCRAILFUSESe.Please

 

refertothesectionRIGHT/LEFTSTEREOSPEAKEROUTP

UTforfurtherclarification.A

 

littleknownfactisthatwhenanyamplifierisope

ratedinthebridgedmode,theloadis"split"

 

betweenthetwoamplifiersinthebridgedconfigura

 

tion.Therefore,an8ohmloudspeaker

 

willbeseenbytheamplifierasifitwerea4ohm

 

load;a4ohmloudspeakerloadwillbe

 

seenbytheamplifierasa2ohmload.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NOTE

 

 

 

 

 

 

 

Iftheconnectionsdescribedabovearefollowedexa

ctly,theGFA555mswillbepolarity

 

 

correct,thatis,itwillnot invert"phase".Anypositivegoingsignalatitsin

putwillappear

 

 

asapositivegoingsignalattheloudspeaker.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DC RAIL FUSES

 

 

 

TheDCRAJ LFUSESprovideprotectionfortheoutpu

 

tstagesandpowersupplyinthe

eventofexcessivecurrentdemandsfromtheamplifi

er,eitherlongtermorshortterm.

If the amplifier ceases to operate, either on one o

 

r both channels, particularly during

highlevelpassages,orlongtermhighvolumeplayb

ack,andthePOWERLEDglowswhile

theTHERMALPROTECTIONLEDisout,thechancesare

thatoneorbothoftheDCRAIL

FUSESonthatchannel,orbothchannels,areblown.

 

 

Your ADCOMamplifier is designedtoactivate its pr

 

otectivedevices reliably, particularly

when the amplifier is carelessly operated well beyo

 

nd its limitations. Other types of

protectioncircuits,beyondthemethodsusedinthe

GFA555msamplifier,suchascurrent

limiting,etc.,usuallyresultindeteriorationof

theaudioperformanceoftheamplifier.

While the GFA555ms will operate dependably in ever

 

ynormal situation, noamplifier is

impervioustoabuse.Thereareconditionswhichmus

talwaysbeavoidediftheamplifieristo

Page 11
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Adcom GFA-555MS manual DC Rail Fuses

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.