Turned the PC off (reboot didn't do anything useful) resulting in huge BANG
through the speakers and again while booting...
[...]
It did do the trick though... all seems to work normal now?
Bert, of course that didn't do any tricks. All you implied was DC Offset by switching off the PC and which can happen always, can happen for everybody, and always happened when it liked to. For years.
Nothing special in your situation. Oh, possibly you implied a new situation for yourself (as in : not used to) because of the Intona, which isolates (obviously). That can matter.
The driver seemingly behaving strange right after install is a Windows 10 thing, as Windows 10 is a no-THING (especially when it is about drivers).
But this is all very well known (by now).
Eh, happy listening ?
Peter