Thread: PC to DAC connection: USB vs. S/PDIF on mobo

Hi all,

I looked around the forums to see if my question had already been addressed, but could not find anything.

I am planning on adding a modestly priced DAC to my PC, something along the lines of a Musical Fidelity.

While USB was never intended to be a music carrier, it sure looks like the audio manufacturers have done a great job patching this wound and making it work.

However, in addition to USB, my mobo also happens to have a coax S/PDIF output.

Before I waste any time comparing the two connection options, does anyone have any experience with this? Is there any reason why I simply shouldn't assume the S/PDIF is superior?

Thanks for any insight!

If the DAC has an async USB input (I believe this is the case with the Musical Fidelity), it is likely to have less jitter than the S/PDIF input.

Both USB and coax are subject to electrical noise.

Optical S/PDIF eliminates electrical noise, possibly at the cost of more jitter.

Some S/PDIF is better than other S/PDIF - some sound cards, such as certain ASUS models and the EMI Juli@, have excellent reputations among audiophiles.

Build quality of optical cables, especially the terminations, is reputed to be important.

Since the Musical Fidelity has coax, optical and USB inputs IIRC, no reason not to sample (or perhaps buy if the price is right) multiple cables and listen for yourself.

Mark,

Yup, the Bryston as plenty of inputs, but it lives in my stereo room, while my PC in in my office. Two different worlds and requirements!

Thanks for the question, though.

Recently trying the SPDIF out on coax of my motherboard. Built in sound card. Pretty nice in fact. An SPDIF converter thru USB is better though not worlds better. Subjectively I give it a 20% difference. So I suggest getting the DAC use the SPDIF a bit. Be confident a USB connection will improve upon that. I even have been taking measurements of such. USB is about 6 dB quieter than the SPDIF out of my Gigabyte motherboard. Doesn't mean they all are. The Gigabyte is a bit better than average as MB's go. Just one more reference point for you to consider.

Now a question I cannot answer is should you spring for a USB converter or something like an ASUS Xonar soundcard. If the built in card on my motherboard is as good as it seems, a Xonar might be a simpler equally good option vs. a USB converter.