[LAU] help with focusrite saffire pro24

Hello, list, I'm in a bit of a hurr and a fix and so I am forced to send this from my phone: so apologies for any typos and misspellings. I am trying to set up a system with ubuntu interfacing with a Focusrite Saffire pro24, none of which are my own or my own choosing. After some fooling with the code ffado recognises the card and jackd seems to interface fine with them. However, no sound will come out of the sound card no matter what I do. Jack sees all the channels and the card lights up like a nice christmas tree, but no joy. I was wondering whether any Saffire user on this list might give me a hint. I can always use my own trusty ittle UA25EX, but the saffire would be more convenient. Anyway... Any pointers would be much appreciated. Cheers, S.M.