Have received one of these amps in trade, and am pleasantly surprised... i'm think i'm one of THOSE people who "get" these amps. Seems one either goes for the 9/15 or this one . Very, very nice clean sound , and delivers a really nice blues rock OD with little effort. Some questions, though; 1- what's with the shelf between the chassis and the speaker? In order to change tubes with it in, you have to take out the chassis! Also, it seems to me that w/o the shelf in place the amp would run a lot cooler, eliminating the need for the muffin fan mounted in the shelf. 2- There seems to be a TON of bass, way more than i'd ever need. I plugged the amp into one of my 2x12 cabs with RI GB's (a Buzz Feiten cab, which is very bright and articulate), and had mucho booominess at anything over 1/4 on the bass control. This isn't that much of a problem, IMO, as turning the Bass almost completely off seems to sound just great to my ear... just seems a bit unbalanced. 3- Does the neg. feedback switch do anything? I can't seem to hear any difference. Is it a trick? 4- i see Fred has taken a page out of Tony Bruno's book, and not provided any tube chart. Grrr.. 5- BTW, i love my Weber p12n in the combo! Can't wait to try out the Goodman... I think a G12H , GB, or blue might make this amp sound a little harsh... though undoubtedly a Rock monster. I just don't think this amp needs any more aggresiveness, and would benefit from a little finesse in the speaker department. 6- ok, so the two 8 ohm outs are for (if using both), two 16 ohm loads, right? 7- mine is dated july /03, i wasn't aware that they were making 10/20's back then? Anyway, cool , simple amp... i can see what the fuss is about, but was glad my expectations were low, as others on this board had owned, and were somewhat lukewarm on this amp, proving once again that you can't please everybody, we're all different, and that's the way it's supposed to be! Still think the shelf is goofy, and Fred, don't put screws into the end grain of 1"x1" pine!