AMB’s WM8741. The Best Portable DAC.

This DAC is based on AMB’s excellent PCB: γ2. I think he does the best DIY projects – all the information anyone needs is there and he has a forum for help too. Great work ! My build follows his parts list, with the following options :

C20, C26 = Blackgate N 33uF, U2 = adp151 9uV noise regulator, U4 = SRC4192, U7 = OPA2365, X1 = Euroquartz Xo91 <1ps rms jitter

A high quality PCB

After making and testing the DAC, I added a CM6631 usb to i2s receiver I bought on Ebay here : US$40.

I also added a power switch so I can use external or usb power because external power can be cleaner and the sound quality improves substantially, and a Texas Instruments ua7805 regulator so I can use a wider variety of input power supplies.

It sounds very good and apart from soldering the two tssop ICs, it was easy to do. Thanks Ti ! The finished DAC is shown below.

WM8741

Click for a bigger picture

I built a second one to play with and recently I decided to blow the dust off and use it inside a PC, together with a Wolfson Wm8805 spdif to i2s receiver. That one uses a Tent Labs XO and poly output coupling caps – no electrolytics in the signal path.  The layer routing shows the board can be trimmed a little to make it fit more easily – cut along the yellow line – and take the audio output from the coupling caps. You can read about that DAC here.

The board can be trimmed a little.

The board can be trimmed a little.

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