Hi Ludwig
Re your problem with WSJT-X.? I experienced the same problem BUT it was with ver 003.? The 'error in sound input' seemed to arise with no input from me - it just happened occasionally.? However I did find that the latest Hamlib update seemed to cause this error so I rolled back to the earlier version and now have no problem even with QMX+ ver 004.? This may help with your problem.
Regards
Greg, ZL4GW