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4 x EL84 in UL PP, 470 B+!! is this right
4 x EL84 in UL PP, 470 B+!! is this right
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Old 14th October 2010, 03:08 PM   #31
kenpeter is offline kenpeter  United States
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Location: Dallas
Papers are papers. I own this tube and prove w. XRay photos.
Regardless RCA theory of operations may teach us otherwise:
Grids in that particular RCA weirdo were NOT wound of similar
pitch. Not even related by an integer multiple...

I suspect to have curves more similar to real 6BQ5 pentode
there may have been no choice but the pitch RCA abused?
This was RCA attempt to clone a popular valve and evade a
patent, not to design a new theoretically ideal beam tetrode
from scratch...

Say one thing, but do another. Some "rules" got bent...

I've also peeked inside plenty of true pentodes that had
excellent gird screen alignment, regardless there was no
beam former (and no special alignment of the supressor).
What defines "beam power"? A former, or G1's shadow?
These are two entirely separate effects that happen to
work well together. But makes naming things that only
use one or the other a job for salesmen.

Last edited by kenpeter; 14th October 2010 at 03:31 PM.
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Old 14th October 2010, 03:15 PM   #32
Salas is offline Salas  Greece
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4 x EL84 in UL PP, 470 B+!! is this right
They had the EL84 from Philips, measured it, and then homed in a beam tetrode equivalent most likely. Those guys could make anything thermionic to their measure. Godfathers of vacuum. Their EL34 equivalent 6CA7 works very well in some amps, even better than a suppressor grid EL34.
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