[LAU] problem with zita-bridge to use two recording interfaces

dear list members, I have a question on using zita-bridge with jack2, obviously I'm missing some detail (?). I'm trying to get two usb soundcards working as inputs for recording. as usual, I start jackd via qjackctl with one of them, say, the soundcraft notepad12fx as hw-device (with -r 48000 -p 512 -n 2). now, I want to add the 2nd interface, my zoom h4. in a terminal I put #zita-a2j -d hw:H4 -r 48000 -p 512 -n 2 I get #Starting synchronisation. and I can see the zita-bridge both in the graph window of qjackctl and in my daw (reaper). the problem is that I don't get any signal from the device connected by the zita-bridge. I have also tried to change both devices - without success. furthermore, I've tried to leave some of the parameters (-p and -n) out. am I missing something? thank you very much for any suggestion! have a good day!