I need help telling if my tubes are bad!

[beachjammer]

Hey guys,
I have a Mesa Boogie .50cal+ head. I have a gig in two weeks and my head started messing up on me today. It started having some static type sounds along with the sound going in and out. This went on for a few minutes and then stopped. Occassionally I can still hear the static sounds but it hasn't cut out anymore.... not yet anyway. My buddy and I seem to think that one or more of the tubes might be getting ready to go out. How can I tell if my pre-amp and/or my power amp tubes are going bad? I need help quick!

Thanks,
Keith

[Rupe]

Re: I need help telling if my tubes are bad!

When is the last time you replaced them? If you use the amp alot and your answer is over one year for the power tubes and 2 years for the preamp tubes, you need to completely retube the amp. Anything less is a shortcut and an insult to tone mongers everywhere [img]/images/graemlins/laugh.gif[/img]
If your tubes are fresh, see a tech asap (you can try running a short patch cord in the effects loop but if this works it is a temporary solution and not a true "fix" for your problem}

[Inazone]

Re: I need help telling if my tubes are bad!

No kidding? I've read about power tubes lasting for many, many years without needing replacement.

[Chuckracer]

Re: I need help telling if my tubes are bad!

They can, but if one is relying on the amp to perform, change them. And carry spares.

[beachjammer]

Re: I need help telling if my tubes are bad!

Well I've had the amp less than a year. I bought it used but was under the impression that it had been recently re-tubed. I think that is true for the power amp tubes but evidently not for the preamp tubes. I read through my manual last night and it described my problem perfectly and said that it was probably a bad preamp tube. It said to replace the one closest to the input jack first and then do the other ones accordingly to fix the problem. Well the first one shattered in my hand after only putting minimal preasure on it to remove it! I ended up replacing that one but still had the problem. Once I replaced the one in the second socket though it cleared my problem up! I'm taking it that both were bad so I'm just going to replace all the preamp tubes because the other two I put in were old ones I took out of an old Marshall head. Thanks for all the input guys!

Keith