So, I have been working on the project rebuilding a totally fried GK 800RB. This think was so fried it you couldn't even see the green on the circuit board, only charcoal black. After replacing all of the power transistors, 50% of the other components and a shorted bridge rectifier (the cause of the above frying) I held my breath and plugged it in...seemed to be good. No smoke or things blowing up. So I take it to band rehearsal last night and hook it up to my Ampeg cabs (1x15 & 2x10) crank it up and all I can say is WOW...I was blown away at how good this head sounded. Very transparent, but got nice and growly if you pushed the boost up some, and did I mention LOUD...holy crap...this thing was blowing everyone away. I only had it set on like 1/3 of the master volume and it was overpowering two 100W marshal JCM800 stacks. If I turned it up any more than that it just got stupid loud...like gut rumbling. My only previous experience with GK heads was jamming through a 400RB that I had repaired for a buddy...and I hated that head. After playing for 3-4 hours on this 800RB I think I might be a convert. The thing that blows me away is that this head is rated at 100W @ 8 Ohms for the high amp (I had my 210 plugged in here) and 300W @ 4Ohms or 200W at 8Ohms for the low amp (I had my 8ohm 15 plugged in here). So I was only running 300W max and blowing away the rest of my band. I think this amp may be way underrated. Blows away my SVT350H hands down, but without the "Ampeg" tone. I can get it close though, close enough for me not to miss the Ampeg. I wouldn't recommend this head if you have a cheap bass though, it's so transparent that it'll pass whatever crappy tone a cheap bass puts out right on through. Great Job on this old 800RB GK, color me impressed.