Problem with pulseaudio showing only 2 input channels

[Autodave]

That was going to be my next guess. NOT! How in the world did you find that and how would anyone know to do that? Amazing. Well done, sir! (Well done even if it doesn't fix the problem!)

[sevland2020]

There's a comment at Ardour forums that may or may not be relevant:

Thanks for the reference but the device is already running in highspeed mode.

Actually I didn't found any way to make the device running with more than 2 in / 2 out with ubuntu / win 10.
So I need to buy a new one.

Anyway, thanks for the help!