I have a decent USB out on my mobo - it works with Vega DAC's Exact mode and ODAC sounds good from it, which I can't say is the case with other mobo USB implementations. However the mobo SPDIF actually sounds better than the USB, at least when feeding the PWD2's XMOS solution. My mobo's SPDIF is not as good as Anax's Denon CDP (after playing with 5-6 transports), but it's still better than many others.

What an audiophile is going to do is to try different options and see which works best. I ended up with an OR5.

PWD2 in order of SQ:

• OR5 USB-> i2s
• Anax's Denon CDP SPDIF out
• My PC's mobo SPDIF out
• PC Ethernet ->  PWD2 Bridge
• USB
• AP1 (without PP upgrade) SPDIF out

Go figure...

I think it's an Asus P7P55D.

I guess the bigger question for me is what kind of "jitter" does the on-board spdif introduce versus a soundcard spdif versus usb?

I would guess that the output jitter of the average onboard coaxial or optical digital output is somewhere around 1-2ns, but who knows. It could vary quite a bit depending on what board and codec is being used. The interesting thing here is that there seems to be more to it than just that. I don't think the Audiophilleo as measured on the output as opposed to the way they measure it is actually <10ps, but it's probably under 150ps at least, and by that metric alone it should destroy ANY onboard sound or sound card, which are usually 500ps+, but it doesn't. Why not?

Well power is one part of it, the Audiophilleo without the PP is bus powered, with a so called "regenerative" internal supply. The OR doesn't use any bus power at all, and the Alpha USB only uses it for the receiver circuitry and isolates the S/Pdif output stage via an ADuM chip.

There's no power advantage to onboard sound or sound cards though, in theory they should be the worst of all worlds being internal to the PC and powered by the motherboard. I can't explain why onboard sound could be outperforming $500 level USB converters.