Tubes Asylum

I thought that the KT77 is a beam tetrode...

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Vinyl Valet

In Reply to: RE: Following, and also my impressions (and JJ's) FWTW . . . posted by JoshT on March 13, 2023 at 14:38:24

Anyway, thanks for the nice comparison.

Open up your mind, in pours the trash. - Meat Puppets, 1987

Follow Ups:

RE: I thought that the KT77 is a beam tetrode... - Tre' 19:21:03 03/14/23 (3)
"beam power pentode" and "beam tetrode" are interchangeable language.

Also "beam power tube". All three have been used over the years to describe a tetrode with beam forming plates between the screen grid and the plate of the tube.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
- RE: I thought that the KT77 is a beam tetrode... - Vinyl Valet 21:09:40 03/14/23 (2)
  But doesn't the pentode have an additional beam forming plate, so the the two aren't exactly the same; tetrode with four elements (cathode, control grid, screen grid and anode) and pentode with five elements, the fifth being the suppressor grid? If there are only four elements in a KT77, why would you want to call it a pentode? Do you believe the two function in exactly the same manner?
  
  Open up your mind, in pours the trash. - Meat Puppets, 1987
  - RE: I thought that the KT77 is a beam tetrode... - Tre' 09:54:43 03/15/23 (1)
    No, a true pentode (el34) has a cathode, control grid, screen grid, suppressor grid and a plate. No beam forming plate at all. Just a cathode a plate and three grids in between.
    some people call a beam power tube a pentode because they consider the beam forming plate to be a fifth element.
    A beam power tube does not function exactly like a power pentode but close enough that it can be a direct drop in replacement. 6ca7 for a el34 for instance.
    Tre'
    Have Fun and Enjoy the Music
    "Still Working the Problem"
    
    Edits: 03/15/23
    - RE: I thought that the KT77 is a beam tetrode... - Vinyl Valet 10:04:51 03/15/23 (0)
      Yes, you are correct in that regard.
      
      Open up your mind, in pours the trash. - Meat Puppets, 1987
Yes, you're right! - JoshT 11:02:13 03/14/23 (0)
Must be a typo on the JJ website because I cut and pasted in their language, but I should have flagged that. Interesting.

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