Why USB to SPDIF and not optical?

I've seen first hand gains from going other than USB into the DAC3. Each step up by way of interconnect seems to gain a darker backdrop, and more ease and detail. Depth as well. the best connection thus far that I've used is via the BNC input jack on the BC DAC3 through a Stereovox xv2 IC.

Via coax things get better over TOS by way of jitter reduction and sound stage acquisition. The DAC3 seems to catch the info and reproduce it with a stronger grasp.

With even the use of an adapter, things are better using coax into BNC... especially by way of ambient recall or retreval of the orig recording venue.

these are incremental increases, yet descernable without too much care in listening. Most noticeable is the jump from USB to coax. IMO.

If of course your ripped info was encoded at more than 16/44.1, then even TOS WILL BE A DECENT LEVEL OF improved refinement over it's USB imput.

These items I've noted too might also be, in part, the result of the jitter or dejittering characteristics of the cable interface being used.

I found it impossible to find a maker of all 3 sorts of cabling, USB COAX, & BNC of the same level of quality to experiment with, so keep that in mind too.

Given all the cables I used are quite modestly priced, I'd submit my findings seem valid enough. No uberexpensive wires have yet to remain here, though several were tried.... some upwards of $750 MSRP per 1M.

Perhaps, having another sound card installed with your choice of interface (coax or BNC) would be an option, and possibly save you on many accounts.

Good luck

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