Hello Tom!
On 23 Jan 98, Tom Scioscia wrote to Rich Lockyer:
 TS>        That's what the Torres catalog says. "The Holy Grail! The best 
L6
 TS> ever made." Probably a relabled 6L6.
I don't trust Torres.
 TS>        Yeah... All I need is carbon residue inside the tube and for the
 TS> thing to short out on me, huh? :)        Let's say I'm running a
 TS> Silverface Fender with a 6V6 power section. What's the normal bias that
 TS> most people set it to? Would it hurt to jack the potential up about 10V?
 TS> Would it even make an audible difference?
Honestly, I've never biased an amp.  I checked the bias on Tom's Traynor 
before and after I worked on it and it was unchanged and matched the 
schematic.
 TS>        So, this confirms my belief that Leo did know a lot more about 
what
 TS> he was doing than CBS. :) Like it really needed to be confirmed, though.
 TS> :)
CBS didn't do anything bad from a design standpoint... at the time, tubes 
were readily available and nearly all tubes on the market could easily 
withstand the voltages they used.  CBS's idea was to bump the wattage up... 
back in the 70s, everyone had to have a 100 watt amp, because that's the 
largest that was commonly available.  CBS started tweaking the voltages, and 
in the late 70s, began rating the Twin Reverb at 120 watts.
 RL>> They know, but the tubes' published specs are ###v, so they built to
 RL>> meet those specs.  Building to exceed the published specs would
 RL>> increase the cost.
 TS>        So, they can't do the occassional special run at the preferred
 TS> specs for Fender or Mesa or Marshall? :)
Major retooling.  You want to spend $100/tube for a special like that?
 TS>        And that was only back with CBS that Fender went nuts on the B+,
 TS> right?
Even your BF Showman is a touch high on the screen voltage.
 TS> If so, that is an ultimately small portion of the market. My
 TS> question is, though, why the hell is the Twin so damned clean and loud
 TS> back in the Silverface models with the B+ that high!?!? :) But the Twin 
is
 TS> running 6L6GCs, though, so that's a small part of it...
This is oversimplified, but I'm not getting into crossover distortion or slew 
rates:
The gain of the tube is basically fixed (depending on how it's biased).
Hypothetically, say the tube has a gain of 10:1.  With a 1v input signal, it 
will dump 10v from the plate to ground (remember, a tube's output is the 
inverse of the input).  At 10v, it will dump 100v to ground.  If you're 
running a 350v plate level, the tube will begin to produce distortion at an 
input level beyond 35v.   Above that, there is no more voltage to dump to 
ground, so the peak of the wave clips, producing distortion.  If you push the 
plate voltage to 700v (the EL34 can handle up to 800), the tube will now not 
start distorting until the input exceeds 70v.  This also doubles the output 
wattage.
 TS> what's in there right now... I wish I had it already. I could go check. 

 TS> remember looking in the back and seeing new tubes. I think that they 
ere
 TS> GTs.
I don't trust Pittman either.  I retubed the Carvin with GT 12AX7s and one 
was michrophonic.  Pittman claims that he buys cases of cheapo Chinese tubes 
and tests every single one of them, keeping only the "best" and those with 
the "hardest vaccuume".  He supposedly sells the rest to suppliers like Ruby 
and Peavey.   Pittman tests the tubes to be good when they're new... the 
complaints I've heard about Chinese tubes is they simply don't last.
 TS>        I could send you the schematic, if you want me to. I have it in a
 TS> JPEG as the guy sent it to me.
Ya... go ahead and email it to me at rlockyer@linkline.com
C-ya! Rich
--- GoldED 2.40
---------------