[R-390] 6080 in place of 6802 - RMS ???

[Joe Foley]

--- Howard Rawls <howard@cconnect.net> wrote:
> Hey Rodney, I used a diode to drop half the filament
> voltage on the 6ba6's
> in my R-390A.........it worked so good I forgot it
> was in there......and
> just recently changed it.....after over 20 years of
> trouble-free
> service.Absolutely no problem with short tube
> filament life. Of course, if
> you are after really really really loooonnnnnggg
> life, I guess it is a bad
> idea, like the fellas say. ;-) .
> Howard
+++++++++
Ok, so let's say that from the theoretical
considerations of this that Dr. Ornitz et al. are
right.

I have no postition to argue that anyway, he knows
more about it than I do.

BUT, is it possible that that theory doesn't take into
account the varing resistance of the partially cooled
filament, it did cool some between pulses where it
would have been reheated in the opposite polarity
voltage if used with AC.

Also, because of the 1/2 wave DC there is a
possibility that the structure is able to dissipate
heat just as effectively at the higher voltage for the
shorter period of time as it would at AC.

Or does RMS power explain it exactly in practice?

Just how do they establish the rated voltage/power?

Duty cycle at rated voltage, guys?

Um,...... sorry,..... I'm an industrial
construction/maintenance electrician.







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