Behringer Umc202hd Linux Class Compliant Alsa Here

A common fix for audio dropouts on certain Linux kernels involves enabling "implicit feedback" for the snd-usb-audio module. Guitarix & Behringer UMC202HD - LinuxMusicians

Start JACK with:

jackd -d alsa -d hw:UMC202HD -r 48000 -p 128 -n 3 behringer umc202hd linux class compliant alsa