In Reply to: feedback applied to grid posted by Ralph on December 27, 2024 at 08:53:56:
Yes, Leak used the Baxandall tone circuit in the output stage. The phono EQ likewise uses feedback from plate to grid. The EF86 is one of my favorite small-signal tubes, and I'm not surprised this unit performs well.
I uncovered two online references with schematics detailing the use of the two control grids of the 6BE6 for audio. Both sources are from the early 1950s, and they show the tube being used as a mixer. Perhaps the question now becomes whether feedback applied to a separate grid with different distortion characteristics is a valid means of avoiding cathode node distortion. I might test this with the choke-loaded follower I'm fond of when my current project is complete.
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Follow Ups
- RE: feedback applied to grid - Triode_Kingdom 14:36:43 12/27/24 (3)
- You might consider an EF86 in ultra linear mode - Ralph 11:50:32 12/30/24 (2)
- RE: You might consider an EF86 in ultra linear mode - Triode_Kingdom 23:30:45 01/01/25 (1)
- One more comment... - Triode_Kingdom 09:55:05 01/04/25 (0)