Seems like only part of a circuit to me. What is the upper stage for? Why the low input impedance? The series output caps?I would hazard a guess that there is a tone network missing from this.
It looks like a unity gain buffer that adds "tube warmth".(Whatever that may be...)
save the board with the tubes and sockets and solder some other circuit on it.
That's actually beginning to make sense. If you move the top tube to the right you can see it is two CC stages with NFB from the plate of the second to the cathode of the first. Overall gain should be about 6 times.CheersIan
Quote from: ruffrecords on July 11, 2012, 03:10:24 PMThat's actually beginning to make sense. If you move the top tube to the right you can see it is two CC stages with NFB from the plate of the second to the cathode of the first. Overall gain should be about 6 times.CheersIanYeah, I wish the original schematic I received had been correct to begin with. The circuit now "makes sense" except what is the design goal of injecting the NFB into the cathode follower?
There is no cathode follower.
Quote from: ruffrecords on July 12, 2012, 02:05:59 PMThere is no cathode follower. Indeed. I've been fooled by the first draft. So now, it's just a two-stage amplifier with 15dB of gain.
@ruffrecords:What does the NFB do to the output impedance? (Ignoring the 50k pot)
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