Well the expected day-long titting about was actually about ten minutes grinning like an idiot and then getting a cuppa. Plugged the bass directly into Channel B, set it to the Bass Amp preset and behold... a rich warm full tone without any EQ. I didn't think the Rob Allen could sound any lovelier but, even through the AER, I'd obviously not been hearing it to it's full potential. As @Bridgehouse says in his initial post Channel B can be set to Line or Instrument but on the Instrument setting it is whompingly loud so I just left it on the Line setting. With the Rob Allen's on board volume up to about 75% and the QSC's Gain set at three (it goes up to twenty) it was plenty for home use, I put it on to the Instrument setting and by the time I had the QSC's gain up to five the room started to shake! I hope I'm not doing anything wrong by leaving it on the Line setting? Anyway, then I tried Rob Allen > Fishman Platinum Pro > QSC, bliss. As I said before, just bass direct into the QSC is the best tone I've ever got from anything, with the Fishman I can then tweak the best tone I've ever had from anything. I spent hours pouring over @Bridgehouse's Interesting FRFR thread and was pretty much convinced by the (mostly) learned and eloquent explanations and arguments, having tried the QSC K12.2 in the shop I was convinced enough to buy one, now I've actually got it home turns out it is your actual bona fide revelation. I have posted this pic on the Show Us Your Rig thread but it belongs here too, RnR killer that it is...