If no one else answers, you can go to Jadis's French website and ask them the question, they may take a few days to reply (get them before the August holidays) but they've been helpful to me in the past. In my JA80s, which are similar, the 12AU7 is the first tube after the input, I believe a phase splitter, then the 12AX7, which is the driver, follows. I'd expect your integrated to work the same, but can't guarantee it.
Hey, at least the piece looks beautiful when it's not playing! Enjoy it, it's really the nicest integrated Jadis has ever made, in my view. Very close in sound to the JA80s.