Streaming - To direct connect or not?

[David A]

The “translation” of my question is what is worst for sound quality: the extra work/noise generated by the second USB network card inside NUC (version B), or the extra devices/noise generated by router (version B)?

I can't answer that question. Surely it would depend in part on the quality of the second network card vs the quality of the router so, given a different system with different network card and router, the answer might be different. Also, when we talk about sound quality we're talking about subjective impressions. One person's sound quality can be another's nightmare which is why we have people liking vastly different sounding speakers and amplifiers.

With both setups you've got the same source, the same amplifier, you're using the same input on the Devialet and the same speakers. The major determinants of the quality and character of the sound are unchanged. You aren't going to change the character of the sound, you're changing something that may result in a slight difference in some characteristic of the signal transmitted to the Devialet which has no affect on the data content of the signal, the bits themselves are going to remain the same. From my experience any change will be a small change in areas like clarity and definition, it's not going to be a change in the character of the sound. Don't forget that in that thread on the Roon site to which I provided a link, Danny Dulai of Roon states that he's uncertain that using a direct connection will make a difference and that he doesn't recommend doing so, he's merely suggesting what he thinks would be the way to do so.

I don't think anyone is going to be able to give you an answer to your question, especially given that we're discussing something that we all make our own subjective judgements about. All I can suggest is that you try it for yourself and see what you think, provided the process of doing it isn't an issue for you and losing the wired network connection to the Devialet isn't a problem for you. Even if you had the same gear as me I'd still say the same thing. Don't go into this sort of change expecting big differences, go into it with an open mind and a sense of inquiry in order to find out whether it makes a difference for you, not with the expectation of getting a particular difference. If you go into it expecting a particular result I doubt you'll get the result you expect. You may get a result you like, I did, but that isn't guaranteed.