#1
Turned my amp on today and it sounded a bit shit..

I looked at the tubes, and one el84 is glowing red hot, and the other one hardly glowing at all.

Can anyone diagnose?

Thanks
Last edited by BenF1966 at Aug 6, 2010,
#2
Quote by BenF1966
Turn my amp on today and it sounded a bit shit..

Lovely technical description. I like it very much.
Marshall amplifiers are the truest purveyors of rock and roll known to man.

"And give a man an amplifier and a synthesizer, and he doesn't become whoever, you know. He doesn't become us."

Holy crap, check this out!
#3
Replace them.
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#4
Quote by Cathbard
Replace them.

+1
Quote by Cathbard
Quote by Raijouta
Unless its electronic drums.

BURN THE WITCH!!!!!
#5
Quote by seemeel
Lovely technical description. I like it very much.


It actually is the way many amp techs would describe a problem like that.


TS, one or both of your power valves has burnt out. The red hot one is pulling too much power and starving the one that doesn't glow much at all. Change them both and it should fix the problem. If it doesn't then it's still a simple fix but it's something that should be left to an amp tech.

Good luck
#6
Just tried it again and it was absolutely fine for at least 20 mins, until I turned it off, then it buzzed loudly as it quietened down.

is it definitely the power tubes? I really don't push this thing that hard..
#7
EL84's are very cheap. Why not throw a new set in? You can determine very easily after that whether the problem lies elsewhere.

No one can diagnose your amp's issue based on what you've said. All we can do is tell you to replace the tubes and see if the problem still exists afterwards.
#8
Quote by CECamps
EL84's are very cheap. Why not throw a new set in? You can determine very easily after that whether the problem lies elsewhere.

No one can diagnose your amp's issue based on what you've said. All we can do is tell you to replace the tubes and see if the problem still exists afterwards.

+1
Plus if on the outside chance that it's something else you'll have spares. If it's been redplating that valve is probably knackered now anyway (or at least on the way out). Either way - buy a new set of EL84s.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band