Hi martyn! Sorry I didn't get get back top you sooner! Your not going to like the Carvin MB210. Just kidding! It should sound great with your u-bass! My bass is the older fretless mahogany without the preamp. As far as explaining what the f-deck does, I really don't have a clue! All I know is it makes my u-bass sound a lot better than when I don't use it. I'm not into the tech stuff, but there are others on this thread who can explain how it works. Upright players love the f-deck and they have a thread about it. Tim Watson uses it and loves it and maybe he will come on and give more info than I can. I use the MB15, but the 210 should be awesome. Good luck!