Roon, Foobar, Jriver all sound different even though they all are bit perfect but that is what my ears hear
I hear the same. When I was using my laptop - off batteries - with several optimizations (windows 2016 core mode, Audiophile Optimizer, JPLAY, Fidelizer Pro, Process Lasso, network off, wifi off, screen deactivated, hybernation mode etc.) I was hearing significant differences between the players I was using, i.e. HQ Player (no upsampling, no filtering), Minimserver, JPlay mini, JRiver.
Connection was always through USB, with or without regenerators / galvanic isolators like the Uptone ISO Regen or iFi iPurifier.
Furthermore, the difference between the stock Windows10 + player (e.g. JRiver) and optimized configuration I described above, with the same player, was very obvious. It was easy to check because my laptop had dual boot. Win10 sounded harsher, fuzzier and flatter compared to the optimized software environment.
Again, I did all these comparisons with DAVE (no HMS yet at the time) and the laptop working on battery.
I cannot offer any explanation about why all this happens, and I am happy to hear from people more knowledgeable than me such the last posters in this thread
Anyway, the trials I did made me think that:
a) DAVE may be less sensitive than other DACs to upstream gear / software, but for certain it is not insensitive, at least in my system;
b) bits are bits is nonsense, in many ways
c) RF is not the only mechanism at play here, hence I am not sure that on optical connection in place of the USB is the ultimate solution to remove the effect (for good or bad) of the source.