Mr White's "Opus", designing a simple balanced DAC

[DarrenWadsworth]

Anyone know where a person can get decals (or...?) relating to audio for the front panel? Like symbols for play, pause, etc?

Thank you

Darren

[JeroenR]

Originally posted by Russ White



Well you would need to input the external clock on the OMCK pin of the receiver, and it is connected to GND. There is no simple way to unconnect it. You would have to cut a pin.

The RMCK (SCK) is output only.

Cheers!
Russ

Hi Russ,

Thanks for the lead. From the datasheet I sort of understand that the receiver should not be in slave mode, the clock should be 2.8224 for 44.1kHz and indeed lift pin 25 (OMCK).

Is it also possible to send the clock*4 (11.2896) from the tent clock directly to SCK from the DAC? The SCK from the receiver would not be connected. Or could this introduce timings/delay issues? The tent clock comes with a /4 output so that would provide both freqs.

What is best to do with the clock ground? Connect to ground on the power supply side or to the receiver side/board?

Thanks for the help,

Jeroen

[Russ White]

Originally posted by JeroenR



Hi Russ,

Thanks for the help,

Jeroen

I have not used the device except in any other way but as a master. so I have never tried what you are trying. So I can't tell you if it will work or not.

The way I read the datasheet OMCK is only used while the PLL is not locked. I am not sure I would bother with that, but 256Fs (11mhz) is just fine there.

I would not use the 11mhz clock independantly as it will be out of sync with the other clocks and the data.

It seems like to do what you want you would need to run the CS8416 is slave mode.

So you would need to generate the bit clock and word clock from your clock (so they are all in sync).

IMHO, its probably not worth your trouble.

Cheers!
Russ

[jonatan_w]

Hi

Got the last board today so it's ready to be put together. I was thinking of stacking all the boards on top of each other like in the attached picture. Is there something negative about using a design like this? The only thing I can think of is the LCDPS board being close to the DAC boards but that shouldn't make any real difference.

Also I was looking at transformers and I found one torroidal, 2x9V 30VA which would work fine. But I also found these two:

1x9V 12VA
http://www.velleman.be/ot/en/product/view/?id=423#

2x12V 12VA
http://www.velleman.be/ot/en/product/view/?id=981

Either using 2x 1x9v for a true dual-mono design or use the 2x12V. They look kind of neat and would do well in a minimalistic design with boards stacked, transformer and connections in the back. What do you think? Should I try these or go with the torroidal?


Thanks

[BrianDonegan]

I was thinking of stacking all the boards on top of each other like in the attached picture.

No picture attached, but the modules were designed to be stacked. I usually place the power supply(s) in a separate stack opposite the power connections of the modules.

The 2x12(12VA) should work.

[jonatan_w]

http://www.diyaudio.com/forums/attac...amp=1211221739

Attachment works for me, the link above should work as well. Anyway I used two distances to make enough room for the components in the bottom. It looks pretty neat and shouldn't be any different to having the LCDPS board lying next to the others instead of under. Or am I wrong?

Btw, very nice kits, very proffesional

[Russ White]

Originally posted by jonatan_w
http://www.diyaudio.com/forums/attac...amp=1211221739
It looks pretty neat and shouldn't be any different to having the LCDPS board lying next to the others instead of under. Or am I wrong?

Btw, very nice kits, very proffesional

Thanks.

Your stack should work fine, as would the transformers.

I would suggest though that you move the power supply to the top of the stack, this will aid with the cooling of the heatsinks.

Cheers!
Russ

[kstlfido]

Thought i'd chime in. Stacking these does make a great form factor.

What I did was remove all the i2s green connectors and run 24awg stranded through the holes. To do this with the USB receiver, I flipped the receiver upside down.

You need to remove the USB boards' analog output green connectors and bend the 12s-spdif selector pins out of the way so it will fit w/o being as high. Or you could use more spacers.

Pics here-

http://kentleech.com/opus-dac-stack/

So it goes like this from top to bottom-

USB (upside down)
Metronome
Left opus
Right opus
Ballsie

I opted to keep the power boards and transformers away- they will be in their own shielded section when I enclose it.

-Kent

[luvdunhill]

Originally posted by Russ White
I wanted to test all of the feature of a couple of our modules. So I rigged up the following.

USB module ---> Metronome(ASRC) ---> Transceiver (WM8804)


I took just BCK/LRCK/DATA from the USB module simulating a CDPro or similar situation and ran it int the Metronome. SCK is an output on that board anyway so you would not connect it in any case.

Then I took the I2S out (including master clock) from the Metronome into the WM8804 transceiver module. The metronome is setup to re-clock at 96/24 with a 256fs master clock.

I set the transceiver module to be in AIF slave mode (AIF clocks become inputs). And used the SPDIF output of the transceiver. This goes out to another dac. Well it works very well. And even sounds very nice!

Now in the pic you will notice the SPDIF input flag lights are red and non-audio LED is green, thats ok because there is no SPIDF input, just output.

Cheers!
Russ

ah, I may have found my answer to my question (latest question at head-fi) ... the above post seems to be the closest I've found. Currently, I am using a "direct" transport to DAC connection using i2s and the requirements for my DAC are 16-bit I2S, 64 BCK/WS and BCK is 44.1kHz * 64, 2's compliment data, WS 44.1kHz.

Can I "substitute" the transport mechanism for the Wolfson 8804, which would configured as: AIF_MS to MASTER, TXSRC to SPDIF, AIFCONF1 to low, AIFCONF0 to low and powered using an existing 10V psu?

[Russ White]

Originally posted by luvdunhill
Can I "substitute" the transport mechanism for the Wolfson 8804, which would configured as: AIF_MS to MASTER, TXSRC to SPDIF, AIFCONF1 to low, AIFCONF0 to low and powered using an existing 10V psu?

My honest answer is, I believe you can, but I have never tried.