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Hi all

Right now I'm in the process of researching the GE - Sylvania 6CA7 and the history thereof. So far as to whether they were pentode or beam tetrode I've gotton conflicting results. But I did some rethinking as to the Westinghouse, they were an EL34 variant aka 6CA7/EL34 type made in Japan.

It seems from the pics I've seen they look like beam tetrodes and quite different than an EL34. Like a BIG 7591. But this is kinda going OT. So if find anything of great significance/importance I'll start a new thread. That is if there's any interest to anyone. They do look beefier though:

Wayne :)
 

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diyAudio Senior Member
Joined 2002
Hi,

So far as to whether they were pentode or beam tetrode

If it's any help, penthodes contain 5 elements. Tetrodes only 4.

The difference between most EL34s and 6CA7s is that the EL34s are all penthodes in the true sense of the word except for the Yugo (Ei) EL34s and their fat bottle 6CA7s.
(I could explain why they're (Ei) building them like this but that would lead to even more controversy I suppose)

The 6CA7s (most anyway) are in essence beam power penthodes (they do have a suppressor grid, g3) in that they also contain beam formers as found in beam tetrodes.

So it's fine if you like to call them (the 6CA7s) a beam penthode just keep in mind it's just not a plain penthode.
Then there are also plain vanilla tetrodes and beam tetrodes.

Hopefully this clarifies it a little,;)
 
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