I have had my B-52 AT212 for about 2 months now (bought it used) and have no problems! recently i turned on the power and let it warm up for ten minutes or so and then turned standby off and played a few things on my clean channel. everything seemed fine it sounded great really warm and still does. but when i clicked over to my first gain channel it sounded like complete crap! everything was muddy and horribly distorted and just plain bad! it has always sounded fine in the past. meanwhile the clean channel still sounds fine!

im curious to know is it my tubes that have gone bad? when i look at them when its turned on they are all lit up! so im not sure im new to tube amps and i dont know if i need to change the tubes or if i have a bigger problem on my hands!

Thanks for the help!
Sounds like your amp just needs re-tubing, if you don't know what you're doing I'd get a tech to do it; I would give you advice but I've never done it myself, sorry.
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Yea if i do re tube it, it will defiantly be done by a professional lol!

but i just wanna make sure thats the problem first before i drop some money on tubes and labor! so i come here first cuz most shops around here will charge to look at it!