I just got my Peavey Triumph 120 retubed and when playing it at band practice, the tone suddenly went to crap. It got all muffled and nasty sounding. i turned it off for a while and turned it back on and it still didn't sound right. Well, when i was transporting it back to my house it got a couple bumps in my car and when I played it at home it sounded alright, but, again, after a while it turned to crap. I'm thinking there is a loose tube or something? I was hoping someone could help me, so what do you think the problem is/what should i do?
Jackson DK2M White
Mesa Dual Rec(2 channel)
Carvin V212
did you retube it yourself? cus when you you change your tubes your supost to get you amp biased. it basically adjust how much power runs through your tubes. then what i did was leave it on standby for about 20 minutes just for the hell of it, im not sure if that part is neccesary though. but yea you should get it biased if all else fails take it to sam ash or w/e.
Washburn X50
Peavey Triple XXX
BBE 462 Sonic Maximizer
MXR M-134 Smart Gate
Furman M8
B-52 LG412
The amp has a non-adjustable bias and i got it done by a professional.
Jackson DK2M White
Mesa Dual Rec(2 channel)
Carvin V212
Take it back to the shop that set it up if you didn't do it yourself. If you did do it yourself, take to a shop ^^.

It's probably like you say, just a loose tube, probably no big deal. Might even be a dodgy valve that was put in.
Ibanez PGM301
Ibanez GRG170DX
Fender Telecaster MiJ - 1986
Swing T-Through

Ibanez TS9DX
Sovtek Small Stone - c.1985
EHX Big Muff
Kimbara Wah - c.1974
Boss GE-7

Orange Rocker 30 Combo

would it more likely be a power amp or pre amp tube? I'm guessing pre amp. Also, how would I fix this myself? I'd much rather do it myself than take it back to the shop, seeing as I do have a certain degree of skill in this kind of stuff.
Jackson DK2M White
Mesa Dual Rec(2 channel)
Carvin V212
So it sounded good at first and then went to crap? Yeah, could be a dodgy tube, it's kinda tough to say; but if it was the bias it probably would sound bad right off the bat.