Power amp tubes on an old peavey???

[Freudian Slip]

Ok, it's stupid question time. I have an old peavey classic vtx 212 amp that I never use. the last time I plugged it in it really sounded like crap. It used to sound goo......, well it used to sound ok at least
It's a solid state pre with two 6L6 gc's on the power amp side. I was wondering if I have to do anything else to this thing to retube it other than simpley swapping out the tubes with a new matched set?

I really have no clue when it comes to tube amps.


Thanks
F.S.

 

[ocnor]

It's a good idea to bias the new tubes. If you don't know what biasing is then you had better start reading or pay a tech to install and bias the tubes properly.

 

[Freudian Slip]

It's a good idea to bias the new tubes. If you don't know what biasing is then you had better start reading or pay a tech to install and bias the tubes properly.

Thanks oconor. Ya I have heard of biasing tubes, but don't know jack about it. I will do some reading.

F.S.

 

[Freudian Slip]

Ah. I see now. It's just adjusting the power supplies to the tubes.
I don't think I can do it on this amp, but I'll make sure.

Thanks again.

F.S.

 

[dementedchord]

just because it has a fixed resustor instead of a pot doesnt make it non-adjustable... the method is basicly to swap out a pir of resistors... it's doable but a PITA... have ya got a schemo of the thing??? there's also the so called self biasing... though that's not used very much with 6l6's...

 

[Light]

just because it has a fixed resustor instead of a pot doesnt make it non-adjustable... the method is basicly to swap out a pir of resistors... it's doable but a PITA... have ya got a schemo of the thing??? there's also the so called self biasing... though that's not used very much with 6l6's...

Before you do that (though really, you should have it done by someone who know what they are doing), figure out where pin 8 is going (and don't touch anything in there, for Christs sake!). That's the cathode. If it's going directly to ground, then it's fix bias, and you need to worry about biasing the amp. If it goes to a resistor bypassed by a cap, then you don't have to worry about biasing - it's self-biasing (also known as Cathode Biased). It's pretty uncommon for a 6L6 amp, but not unheard of.

Better yet, take it to a electronics guy who can deal with it for you. Let him worry about getting electrocuted. (I should really take my own advice on that one.)


Light

"Cowards can never be moral."
M.K. Gandhi

 

[Light]

Oh yeah, and you can apparently get any Peavey schematic from the factory for like $2.50. If you ARE going to go in there and muck about, get the schematic.


Light

"Cowards can never be moral."
M.K. Gandhi

 

[Freudian Slip]

Before you do that (though really, you should have it done by someone who know what they are doing), figure out where pin 8 is going (and don't touch anything in there, for Christs sake!). That's the cathode. If it's going directly to ground, then it's fix bias, and you need to worry about biasing the amp. If it goes to a resistor bypassed by a cap, then you don't have to worry about biasing - it's self-biasing (also known as Cathode Biased). It's pretty uncommon for a 6L6 amp, but not unheard of.

Better yet, take it to a electronics guy who can deal with it for you. Let him worry about getting electrocuted. (I should really take my own advice on that one.)


Light

"Cowards can never be moral."
M.K. Gandhi

Thanks Light. I just can't pay someone to do that I've got all the stuff to do it. I will follow the 8 pin taking care not to get zapped by a cap. I've been shocked so many times that I think I am immune I'll take care not to work on it in the bath tub though I'll see if I can get a schematic. I bet there is a scan on line somewhere.


Thanks again.

F.S.

 

[Light]

I will follow the 8 pin taking care not to get zapped by a cap. I've been shocked so many times that I think I am immune

Not to that shock you aren't. If you are going to mess around in there, drain the caps first. If you don't know how to do that, don't mess with it.


Light

"Cowards can never be moral."
M.K. Gandhi

 

[cecerre]

So...I have been following the thread. I too have an old vtx and put tubes in it about a year or two ago. The originals lasted forever, however, the newer GTs are starting to sound kind of crappy again. I didn't know anything about re-biasing at the time, and I am interested in any info you garner about the amp.

Thanks