I´ve got the same issue ...
I added (to /etc/pve/qemu-server/100.conf) VM 100 is a Win10 machine this line:
args: -device intel-hda,id=sound5,bus=pci.0,addr=0x18 -device hda-micro,id=sound5-codec0,bus=sound5.0,cad=0 -device hda-duplex,id=sound5-codec1,bus=sound5.0,cad=1
Device Manager in...