Some drivers have error detection/retry added. Do we know if this is the case for Eitr?
AFAIK Eitr uses generic UAC2 drivers. But the device itself can do a good job on galvanic isolation and filtering the incoming noise. So device can be more or less sensitive to USB cables. In honesty, I didn't test fully how sensitive Eitr is to USB cable used. I might do that in future, out of curiosity.
Thanks again for the precious advice. Still i feel that the performance of a very well designed and built usb to spdif converter should not vary remarkably using different combinations (USB and coaxials/AES) of cables of decent quality. Then i have also the feeling that in general balanced connections both digital and analog are intrinsically more resilient to noise and interferences. For this i prefer AES cables.
I also understand that to make an excellent DDC is not a trivial task at all. Thanks again.
TBH I didn't play much with USB cables and Eitr, I've been using AQ Coffee and Cardas USB from before and both work well on various DAC's, same is with the Eitr. But I didn't compare them on Eitr to a generic USB cable yet.
S/PDIF is another story. Sound from QED digital coax of 1 m and self made Supra Trico cables of various length is quite different. QED with overblown but not best defined bass and rolled off (though natural sounding) treble sounds inferior. Also, sound through 40 cm Supra with vdH RCA connectors (screwing contact only, no soldering or crimping) or with Neutrik cheap connectors (gold plated brass) is again different, with Neutrik RCA cable sounding with bit more rolled off treble. Also length makes a difference in sound. I was comparing few days ago and I must admit I possibly like the best how 20 cm vdH connectors Supra Trico sounded even better than 40 cm with the same RCA connectors, though the difference was thinnest here, sound was pretty similar. I tried also 80 cm Supra coax with vdH connectors and again 20 cm one sounded better, having a better 'directness' in sound.
How different it is to you, how big the difference is, how important it is. it's up to a personal subjective evaluation, however one thing is true: until you try it it's speculation, only when you do try to compare it you can decide for yourself if it's audible or not to you, significant or not. But in the end, you decide for yourself.
You mention decent quality. Well when it comes to S/PDIF coax, some audiophile coax cable with single noise shielding use it naturally for the negative signal as well, having no other option. What do you think, does this compromise quality?
I received a recommendation for certain non-expensive Belkin cable (said to have outperformed many audiophile digital cables) and moderately expensive Puresonic gold plated RCA connectors (low on mass, copper used instead of brass). Connecters are ordered (thought on back order at web shop so it might take bit longer to receive them) and I'll solder it and test it gladly when ingredients arrive. Until then I must take some further tests on finding the best length. Whether it's better or not than current coax I use, I'm yet to hear, but looking forward to test it. I'm not certain of Supra's value as a digital coax. All I know is at least it uses double shielding, so you don't have to use its outer shield for signal.
AES/EBU is better than S/PDIF, independent clock signal will introduce less jitter, and connectors are also a better fit for digital audio and can meet specification impedance, unlike RCA.connectors. When this is an option, of course. It's pity (but typical) that worse options are used as a standard
anyway, perhaps because of this various digital RCA coaxes offer audible differences in sound related to cable, connectors and lenght. I wouln't wonder if there is less difference with AES/EBU.
