rca grayplates vs. blackplates 6v6's

Rockmonton

Infected with Altecitis
i have a matched quad of rca's pulled from an old scientific carrier preamp output stage, just wondering how to tell the difference, and if i could run them in place of el34's or 6v6's (with a bias change of course) to tone down a guitar amp of mine, actually they may not fit, but still.... any info on these Rca 6v6's
 
If it has EL34s, it probably has too much voltage for 6V6s. EL34s are usually run at 400-450V, 6V6s are rated to 325 max (though Leo Fender pushed 'em close to 400 in some of his amps...)

6V6s should survive biased to a very low current (20 mA each or so) but I don't know how the tome would be...
 
Knowing it is not an absolute, given the choice between tubes identical in all respects except the plate color I would go for black over grey every time.

Possibly when black plates were more common the QC was better, but black plate 12AX7s to me sound better than the grey plates. Same for 6L6s, black plate Sylvanias sound better than grey plate GEs. The black could have nothing to do with it, but another example are the old oval plate RCA 6BQ5s. I always prefered the black ones over the greys.

As far as using any other tube type in an amp that calls for an EL-34 it will take more than bias adjust to make it happen. Seeing as there are many inexpensive EL-34s on the market it sounds like a waste of time to convert to 6V6s.
 
yeah the extremley high volume was my major concern, and was gona clean up parts, measured the b-rail and well its a lot higher than it should be, about 520 volts so i guess its a no
 
Power is only part of the issue with volume. Speaker efficiency is another. If you can deliberately run your amp into an inefficient speaker, you'll drop the volume a bunch.
 
ahhh, but i just cant get the same kinda tone, i've got less powerful speakers that are quiter, but in music its all a quest for the prefect tone
 
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