Hey Everyone! I'm in the market for an Ampeg Fliptop tube amp. I played my teacher's b15 a few weeks ago and immediately loved how my upright sounded through it. I've been scouring Craigslist everyday along with ebay, this forum, and some other places but haven't seen too many B15s. I have, however, seen a lot more SB12's (and at a more affordable price, around $600). I've never played one and was wondering how they compare overall to the B15. Please don't try and convince me to buy something besides an Ampeg, I'm strictly looking for a comparison of these two amps (or the fliptops in general). Thanks!