Arcam rDac User Manual

InputStagesandswitchingCircuitpages2and3
TheinputsaresplitintotwogroupswiththeWolfsonSPDIFreceiveratlocationIC201dealing
withOpticalandCoaxialselectionwhilsttheMUXatlocationsIC202AIC202BandIC205A
switchbetweenSPDIF(optorcoax)andUSBorKLEERundercontrolfrommainmicro.
SPDIFinput
TheWolfsonWM8805SPDIFreceiversuppliesdatainaformatofData,LRCLK,BCLKandMLCK,
theoutputofIC201runsdirectlytotheDACviatheMUXatlocationIC202Awithexceptionof
theMCLKthistakeapaththruIC203aspartoftheMCLKMUXbetweenUSB/KLEERandSPDIF
MCLK’s.
USBinput
TheUSBdataarrivesatCON100beforetravelingtotheUSBstreamingcontrolchipatlocation
IC103viatheESDprotectionChipatlocationIC101thechipisloadedwiththeDCS
asynchronous/isochronousinputsystemfromIC100atbootup.
IC103hasitownMCLKsourceatlocationIC204anotherWM8805thistimeusedasanadaptive
clocksourcetheoutputisbufferedbyIC203C
TheData,LRCLK,BCLKareswitchedtotheDACviaIC202BwiththeMCLKcomingviaIC203.
DACandAudioStagescircuitpage4
TheWolfson8741DACcanbefoundatlocationIC301andtakesitssuppliesfrom3V3Dand
5VDAC,dataentersthechiponpins1–5andshouldbeseenasbelow.
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AnalogueaudioleavestheDACasbalancedpairsonpins16/17(left)and12/13(right)audio
thentravelsthruandfilternetworkenterstheOp‐ampatlocationIC300a/b(L/R)andthen
ontoIC302a/b(L/R)outputmutingistwofoldwithbothDACmute(transistormute)andfull
mute(relay)theDACmuteisprovidedbytransistorsTR302andTR305switchingtheaudio
downto0vthisunderthecontroloftheDACMUTElinefromIC107,therelaymuteisprovided
byRLY300andtriggeredfrom2linesonebeingthepowerdetectsourcedfromD400atpower
In–underlowpowertherelaywillcloseat5.3vD.CandisflippedbyIC105incombinationwith
IC104theoutputofIC104islowtomutetherelayisswitchedbyTR300.
Pinloc Signaltype
Pin1 LRCK
Pin2 SDATA
Pin3 BCK
Pin5 MCLK

Arcam rDac Specifications

General

Outputs	RCA
Sample Rate	Up to 192kHz
Bit Depth	24-bit
DAC Chip	Wolfson WM8741
Sample Rate (USB)	Up to 96kHz
Sample Rate (S/PDIF)	Up to 192kHz
Output Voltage	2.1V RMS
THD+N	<0.002%
Type	Digital-to-Analog Converter (DAC)
Inputs	USB, Optical
Weight	700 g
Power Supply	5V DC