Tube DIY Asylum

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RE: Interesting circuit.

Posted by Triode_Kingdom on March 5, 2017 at 08:41:16:
Not to get into a long-winded discussion about this, but ... :)

I have to disagree regarding the 811A. I used them for years as linear amplifiers in audio-modulated RF service (single sideband). Their IM and THD are not significantly different than other tubes. As for the 6W6, I haven't used them myself as power drivers, but they do have huge peak current capability due to the robust heater design. That's the same reason I used a parallel-connected 6BL7 follower to drive each of my 211s. Can't speak for the Altec, but in my case, distortion measurements indicate no perceptible change as the output tubes enter A2. Distortion goes up gradually with increasing power, but there's no "step" at A2. That tells me the low output Z and power delivery of the followers is at least the equal of an IT.