Why USB to SPDIF and not optical?

I believe the USB Bel Canto Link is just that, a soundcard. Maybe my original question should have been - do I need to upgrade the soundcard of a Mac mini?

Generally speaking, Macs don't have sound cards that can be upgraded. You can run an external sound card, such as a Lynx, in a Mac desktop. There is no way to put one into a Mac laptop or Mini, although I believe there are some external solutions.

I think it's erroneous to call the Bel Canto Link a sound card. It is a converter with added value.

One last potentially obvious question...

I have a minipc (like a mac mini, but wintel based - made by Aopen) with a realtek high definition audio output section on the motherboard...

If i was to hookup up one of these Bel Canto usb gadgets we started the thread with, then i would be bypassing the Realtek to use the bel canto in the digital bitstream on it's way to my Dac3?....

The reason i asked.. is that i just installed the foobar2000 player with the wasapi plugin that bypasses all the windows digital processing and volume controls.

That actually made a huge difference already...

wondering what the bel canto doohickey would do in addition (assuming it might do anything)?...

Maybe TTVJ is on my next email agenda for a try out... :-)

Just improving the Toslink from the Mac will reduce jitter a little, but it does not change the clock inside the MAc, which is the true source of the jitter.

If you go USB to S/PDIF, there are three advantages:

1) Eliminate the Toslink optical conversions as a source of jitter
2) Establish a new low-jitter clock to replace the one in the Mac
3) Output from S/PDIF coax to the DAC, whic has the opportunity to have lower jitter than the Toslink (depending on implementation)

BTW, this can still give you galvanic isolation (just like the optical) providing the converter is properly transfomer coupled.

Steve N.
Empirical Audio

Steve,

Since you seem to be an expert in "jitter", can you provide a link to any qualitative data explaining this phenomenon, in layman's terms?

Lance