Hi Bruno,
I'll give it a try :
3. If I proceed with decoupling the ground I MUST make certain that the card is isolated or loud noises even damage might occur to the DAC.
5. Is this still correct for both NOS1 and NOS1A?
This is not so easy to guarantee because of the so many other things (in the house) involved, and all I can really say is that isolation at both ends is a consistent situation. Not-isolated at both ends is as consistent.
Damage to the DAC ? nah ... I don't see that happening. But it wouldn't be good for speakers when this starts to happen and is left like that for many hours. And, the only situation I know of that such a thing happened was when only one side was isolated. And then still this will have been incurred for by the "house" situation.
Although I can't guarantee that either, I think that the NOS1a is hardly prone to the "noises" you refer to;
There may be one "plop" when e.g. the USB cable is detached and that is it. So personally I never ran into the situation that the slow oscillation occurs and the plopping keeps on going on without USB cable attached. This, while with the normal NOS1 this could sure happen in my situation.
6. Is this still correct for NOS1 in light of the new software? v2 (too early to say with Win10, I understand)
This is all not related to the software at all. That is, if you mean the noises. What sure *is* related though is the consistency with the sound (so to speak) if it all were to be about my own judgment and how I see and say that SQ improved and such. To this regard it is to be note that :
- I use the NOS1a;
- I use the BNC 75 Ohm impedance Blaxius Interlink (with 75B (75 Ohm BNC Output) NOS1a upgrade);
- I use the Clairixa USB cable;
- I use of what I think are the best speakers for resolution (very high efficiency hence speed).
- I sure use the at both ends isolated USB interface with the Silverstone card (NOS1a has Sw#3 for the job and Up means isolated at the DAC side).
- I use a very lean Audio PC with the music elsewhere (LAN);
- I control that PC by means of RDP.
This all matters (so also the last topic (RDP)) and all can be mimicked although having the same speakers is a bit crazy perhaps (but everyone can since it is a commercial speaker). But the speaker (and amplification in there) also is the least influencing if it were to be about the consistency of sound and for example thinking of the difference between W8 and W10; it only allows me to hear things better - at least that is my view.
Now I hope this wasn't a too long answer ...
Peter