Peavey Deuce VT212

[Jabberwocky]

Having trolled the dark streets of Sound Modelling amps (Mainly Line6) I find that I am just a simple guy at heart, so I have gone back to my trusty Peavey Deuce old lady frightener. The Automixer and the channel controls give me all I need and at a helluva volume.

I am in the process of giving the old girl a serious makeover and have purchased a new matched quad of Svetlana 6L6 GC valves to replace the current Sovteks. Svetlanas, I hear, are top of the line for a smooth soundstage and are especially suited to that clean Fender twang. However I hear scary words such as 'Set the bias' and 'Burn in the valves'. Any enlightenment on these issues will be welcome.

[Caevan O’Shite]

Assuming that the amp has a bias control pot (usually internal), the "idle", if you will allow a vague analogy, for the current-draw can be set for the output-tubes. The bias adjusts the amount of negative-voltage applied to the control-grid inside the tube.

 

Too little negative-voltage there, and the tube will draw too much current, too fast. The tubes will overheat from this, and real damage to the tubes, output-transformers, and other components can result. At the very least, the life of the output-tubes will be reduced.

 

Too much negative-voltage there, and the output-tubes will not draw current properly. It will produce an unmusical sounding type of distortion and the amp will sound choked-off, weak, weedy, raspy, cold and thin.

 

The proper bias is a controlling negative-voltage that is somewhere within a safe operating range, that sounds good to YOUR ears; if this is too much for you to do for yourself, don't feel bad, just take it to someone who definitely knows what they're doing, and then whenever the time comes to replace the tubes, you can likely get by very well with a matched set that is the same as those the amp was biased for this time.

 

Now, the bias can and will likely drift a little over time, as the tubes and other components wear and the AC-voltage from the outlet in the wall varies, etc. It's just the nature of this interactive, old-tech topology; liken it to an old car or motorcycle that's brilliant, but needs a little extra care and finessing to keep happily running along. It isn't a bad idea for the bias to occasionally be checked, and tweaked as required; if you want to do this yourself later on, there are ways to simplify the task so that a digital multi-meter ("DMM") and a screwdriver can be used to keep things in line. But initially, I'd recommend having a well-equipped professional set the bias, and help you zero in on what's right for you, bias-wise and tube-wise.

 

As for "burning in the valves", someone else please correct me if I'm wrong, but I don't see any point in that at all.

 

Now, when replacing the filter-capacitors in the power-supply, it is most ideal to "bed in" the filter-caps, so that they build, hold, and discharge a sufficient charge, and have a full and happy service-life...

[Gabriel E.]

Yeah, burning in tubes is BS. Kind of defeats the purpose of getting new ones.

[Caevan O’Shite]

Y'know, I've found that I love both new-string and new-tube sounds...

[Melvins Poiuyt]

My suggestion: hire a squad of gorillas to schlep that thug around for ya. Old lady frightener? That thing'll stun buffalo at 300 yards. My gawd, whattaya, playin' football stadiums?

[Jabberwocky]

Thanks for the advice CaevanOShite.....still sounds scary so I will take your word for it and get a pro on the job. The new valves sound awesome though.....very clean and crisp but with something lurking in the background that says 'take cover'......crunch is not so magical once the gain goes beyond 8 (out of 11...!!) but what the hell....tube screamer does a marvellous job......

 

And yeah MelvinsPoiuyt.....the Deuce is a little top heavy. Not keen on Primates....there are enough of those at gigs already !! so I employ 4 buxom girls, topless,....a blonde, a brunette, a ravenhead and a redhead to schlep the Deuce into gigs for me. And after one bad experience, I now issue a health warning to venue owners that Buffalo must not be allowed to enter without ear protection........

 

Wish I was playing football stadiums !!

[Caevan O’Shite]

A ravenhead girl, eh? I prefer girls with human heads, myself...

 

Oh, by the way, whenever you replace the output-tubes, it's a good idea to also replace the "phase inverter"/driver-tube (the 12AX7 or 12AT7, etc. tube closest to the output-tubes). They work together as a team in the output-section, and burn-in and wear-out together. And in most amps (ask on the "Feel free to ask Myles"-thread if you want to be sure about your specific amp), a "matched phase inverter" is every bit as valid to performance and tone as matched sets of output-tubes. (In this case, the "matching" involves testing and selecting the similarities and balance between the tube's two internal triodes.) Some amps use a design where little or no benefit is gained by an MPI, but most will benefit greatly.