Cyrus 8 DAC - QUIESCENT CURRENT SETTING; Quiescent current setting (no signal condition)

QUIESCENTCURRENTSETTING
©CyrusAudioLtdJun2014 17 Cyrus6DAC,Cyrus8DACservicemanualIssue1
Quiescentcurrentsetting(nosignalcondition)
Quiescentcurrentsettingshouldalwaysbesetcorrectlyafterrepairofthepoweramplifier.If
incorrectly set, the amplifier sonic and technical performance will deteriorate, and if set too
high,thereisapossibleriskoftheamplifieroverheating.
Thefollowingprocedureshouldbefollowedexactlytosetthequiescentcurrenttothecorrect
value.Ifthequiescentcurrentwillnotsetcorrectly,thismayindicateapoweramplifierfault.
 Switchoffthepowertotheamplifier.
 Disconnectallloudspeakersordummyloads.
 ConnectaDVMsettoreadmVtoSK205.
 Switch on the power to the amplifier, and bring it out of standby. If a mains voltage
adjuster(variac)isavailable,useittosetthemainsvoltageprecisely.
 AdjustthequiescentsettingpresetRV201sothatthemeterreads8mV
 Proceedto connect the DVMtoSK206.Adjust the quiescent  settingpresetRV202sothat
themeterreads8mV.
 Leave the amplifier to stabilise for fifteen minutes and repeat the adjustments for both
channels,takingthesettingto3.2mV0.25mV.
 Checkperiodicallyandadjustifnecessaryto3.2mV0.25mVuntilsettled.Alsoensurethat
thenominalmainsvoltagehasnotdrifted.
SK206
3.2mV
RV202
SK205
RV201