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What is a good value for B+ ripple on 480VDC
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Circlotron:

--- Quote from: wagnerlip on December 05, 2018, 07:09:56 pm ---It is just me and my 50+ yrs knowledge of vacuum tubes is just vanishing away, or those output 6L6's have the cathodes floating?

--- End quote ---
Yeah, that is a bit naughty.
vk6zgo:
Dunno why I didn't pick up on something in the OP in my earlier answers "way back when", but having
a higher hum level on the higher voltage HT for the Output tubes was a standard design in the old days.
It saved having to fit more high voltage, high capacitance, high cost electrolytics.

The hum is "common mode", so is present at both push pull anodes, with the result that it is cancelled in the output transformer.
The stages up to the phase splitter need much better HT filtering, because they are not balanced.

With the " Type 3 " amplifiers we used in my old job, you always knew if one of the EL34s had croaked, because you could hear audible hum.
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