Telling if tubes arer still good.

[zero element]

Im debating whether or not to change the tubes in my Peavey Ultra 60. Is their a way to tell if you need to change the tubes or if the tube are still good. The ones in their for pre amp are groove tubes, gt12ax7r and they look brand new. The power tubes are Sovtek? They are 6l6gb and look a little worn down but not bad. So can I tell by looking at em if they new a changing or if they still got some life in em.

 

[marvar]

Re: Telling if tubes arer still good.

You cannot tell a thing about the condition of your tubes just by looking at them. I've seen brand new tubes that were bad, and tubes that had the silkscreen completely burned off, and still be good. How old are they? have you done the tap-test? usually a bad tube will manifest itself by: loss of tone and volume or, loud squealling, and/or increased noise.

 

[anewdefguitarist]

Re: Telling if tubes arer still good.

tap test?? could you elaborate?

 

[zero element]

Re: Telling if tubes arer still good.

when using the overdrive channel on it, its a bit distorted but not bad(might just need to goof around with some setting for thats). When I shhok one of the power tubes up to my ear it sounded like a light bulb that blew so does that means its bad?

 

[marvar]

Re: Telling if tubes arer still good.

when using the overdrive channel on it, its a bit distorted but not bad(might just need to goof around with some setting for thats). When I shhok one of the power tubes up to my ear it sounded like a light bulb that blew so does that means its bad?

That sure doesn't sound good!
The tap test is: turn your amp on- don't plug your guitar or cable in- be sure the speaker cable is hooked up, make sure the amp isn't in standby- turn the volume up some, then lightly tap on each tube with the eraser end of a pencil or a small piece of light wood, listen, if you hear the tapping sound coming out of your speakers, chances are the tube is bad- you may hear a slight bit of noise when you tap the preamp tubes, a little is ok- if you hear the tapping when you tap the power tubes, it's microphonic, an needs to be replaced. If you have experienced a loss of tone or volume, the tubes need to be replaced. Pre amp tubes can last many years, power tubes may last about 6 mos under hard use, maybe a year under occasional use.

 

[LesStrat]

Re: Telling if tubes arer still good.

When there's no glow and no sound, the tube is bad.

 

[kmcguitars]

Re: Telling if tubes arer still good.

when using the overdrive channel on it, its a bit distorted but not bad(might just need to goof around with some setting for thats). When I shhok one of the power tubes up to my ear it sounded like a light bulb that blew so does that means its bad?

Sounds like filament rattle. If the tube still works? It's seen better days. Time to replace them.

 

[Gearjoneser]

Re: Telling if tubes arer still good.

It doesn't sound like you need to change the pre tubes, but I'd suggest buying a set of JJ's or Svetlanas. If your amp is 60W, a duet of them is pretty cheap.
$25

 

[zero element]

Re: Telling if tubes arer still good.

Alright thanks, Ill buy a set of power tubes and replace them.