Hi, I've got an asrock 939dual coming in a few days, and since it does not have spdif out I began thinking
The mb uses the realtek acl850 chip(as almost,if not all, ac97-solutions do today), and by looking at the reference design and the technical documents realtek have on their website I realized that it should not be too hard to hook into the chip directly. Pin 48 is the spdifo(sp/dif out) and what I _think_ is that using this as digital coax should quite simple.
By using smd grabbers, just a copper wire, or soldering, I would think it would just be a matter of making the cable to go to your dac?
Though it is ofcourse possible that the sp/dif is deactivated in some way, it would have to have been done in hardware, as the generic realtek acl850 drivers work fine(I've read in some asrock thread).
The tech docs also talk about a "Power-off CD function" where if you disconnect the 5v from the chip, the analog(opamp) section will be disabled, and you can pass "cd output directly to speaker". Disabling the opamp section will remove any bad sonic qualities the integrated opamp has, and give you a much purer signal for your own amp.
While I doubt I'll be disconnecting the 5v pins, I will try the spdif out as soon as I get my system up and running in a few days, in the meantime; any thoughts or perhaps any brave souls that have tried this?
Tech docs and ref design:
Generic acl850 driver for windows: