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Original Message

RE: Jon Broskie says they are the same

Posted by cpotl on September 21, 2020 at 07:58:48:

"If you read Tubecad, Broskie, who doesn't shy away from making provocative generalizations, says the circlotron and the Futterman output stages are fundamentally the same."

That's not quite what he says. His whole point in that article is that what really matters, when you analyse the circuits, is where the signal reference point is in the output stage. As he says, the signal ground reference point is different in the circlotron and in the totem pole, and so they behave differently. However, he also points out that with a small change in how the ground reference point is set (by taking the signal ground to be at the midpoint between the two speaker terminals rather than at one end), then the totem pole would become operationally equivalent to the circlotron. I think that is an uncontroversial point.