a lot of guys who use jcm 800's have the gain circuit modded. they also swap out the tubes. i have 2 marshall valvestate 100 heads. i actually prefer them to any of the other marshalls, including the 800 and t/dsl's. but the best amp i've ever used is a mesa rectifier. single, dual, triple. doesn't matter. they're great. the peavey xxx and 5150 are also good. it's cool if you want a marshall but if you're buying it for its name you should really think twice. there's better amps to be had.