I have the popular Biostar TF7050 motherboard and Hardy Heron. Once upon a time, all I had was a laptop and I bought a pricey USB dac, and that's what I'm using now hooked up to my stereo system. However I'm starting to be interested in playing movies with surround from my computer, and it doesn't make much sense to keep the DAC for stereo AND use the analog outs for multichannel. People on stereo fora claim that pretty much any soundcard isn't acceptable to be plugged into their precious systems and that tossing my DAC constitutes a 'downgrade'. I usually don't listen to such people but i also don't want to kick myself later.

I haven't had a chance to try out the sound quality of the analog outputs but the sound quality of records that I have recorded via the line in, when played back through the DAC, sound very good, so I imagine the line out sounds just as good. Ditching the USB might also help with my maddening difficulty with getting things like youtube videos and mplayer to play through the damn thing.

BTW, what's the difference with Alsa and OSS?

I would suggest A-B'ing the USB DAC with the line outs and compare with your own ears. Everyone has different hearing sensitivities and tolerance for audio quality issues.

For most media PC playback, you'd want to use the SPDIF digital out anyways, bypassing the motherboard audio DACs, eliminating the biggest source of audio quality variation.

ALSA and OSS are the Linux sound driver "API's", or driver frameworks:
http://en.wikipedia.org/wiki/Advanced_Linux_Sound_Architecture

ALSA replaced OSS, but some apps still need OSS for sound.

I never thought of using SPDIF. I suppose it would sound just as good as using my DVD player SPDIF->surround processor that way. Good call.

One thing though, if I have surround sound, I can't output it over SPDIF and have my surround processor decode it, right, unless it happens to be DD or DTS from a DVD? If I have an anime.mkv show with surround, I can't listen to the surround with SPDIF right? I would have to hook up both my analog and SPDIF from my computer (no problem) and use the analogs for certain multichannel material. But my music could go over SPDIF, and music is most important to me anyways.

If I have some 48khz and/or 24bit flacs, is there any problem sending them over SPDIF, or should I make sure I record my vinyl in 44.1/16bit FLAC?

If a video file, like and AVI or MKV, has "surround sound", i.e. a multichannel DTS or DD/AC3 audio track, then you should be able to send it out over SPDIF to an external decoder. Te media player software you use will usually let you select decoding or SPDIF out.

But using both your analog outs and SPDIF outs is another solution.

SPDIF can carry up to two channel 24 bit, 96Khz digital audio. So yes, you could record your vinyl to 24/96 wavs, and play them back unchanged over SPDIF. Many audiophiles archive their vinyl this way. Just be sure you use a soundcard wth good quality ADC's that are true 24/96 devices. Above all- toss any Creative/Sound Blaster stuff ;)

I've been trying to avoid buying a soundcard, and just using the Biostar's line in. It's probably not ideal, but I don't want to load my system down with a PCI card right now, that was kind of the whole point of going mATX with decent onboard.

My 'reciever' is actually a Technics SH surround processor.

To clarify, you can *play* 24bit/96Khz audio via almost any sound card or on board sound over SPDIF, just be sure your external receiver/processor has 24/96 DACs and accepts 24/96 data.