max length of toslink or coaxial digital cable without signal degradation?

I hope this is a fairly straight-forward question and doesn't involve too much subjective opinion.

I have an Oppo 203 in my video stack, quite separate from my audio stack.  If I were to use the Oppo as a transport for a (hypothetical) DAC (sitting in the audio rack), I'd need perhaps an 8' cable to connect them.

Would that distance lead to signal degradation?  Is one transmission mode superior to the other for these kinds of lengths?

Optical works great over long distances. What matters is the jitter rejection capability of what you put at the other end.
Correct me if I am wrong but the Oppo-203 has 2 HDMI outputs, one video and the other for audio only. If you use a 3-5m FIBBR HDMI cable you should get perfect sound. Otherwise you can use a XLR cable to the DAC. Optic is also great as Shadorne says though throughput is limited to 24/96.
In general coax should be better. Toslink has slow transitions that can convert system noise into jitter but doesn't have reflections, doesn't make ground loops and is not sensitive to ambient electrical noise. All comes to jitter that converts to noise. There is no way you can measure  anything so the best way is to try.  Perhaps you can borrow cables from local stereo store.  

OK, so three posters and four answers.  Isn't the internet great!





Back of the Oppo unit.  I don't see XLR.

As for HDMI, Google tells me inputs are rare on stand-alone DAC's.  Essence and NAD M51.  What else?

Any other votes for optical vs. coax, assuming modern, highly-engineered, jitter-rejecting DAC?

opinions vary, but the majority view is that optical is better over long distances--less prone to emi/rf interference. if you think about it, carriers use fiber optic to connect between cities and countries.
Its true that optical fiber is better for long distance signal transmission but that requires the use of high quality glass fiber - as opposed to plastic, which means a more expensive cable. Also watch for the bending radius.   

Just get one of these in the length you need.  Better than glass.

If you are really worried about degradation, put a reclocker like the Synchro-Mesh in-line.  Then its a don't care.  The reclocker will also provide galvanic isolation as well as upsampling to 24/96.

Always use at least 1.25m length for coax:

Steve N.

Empirical Audio