huh ?

[Jaap]

Just for fun a schematic from 1958, published in the Dutch magazine "Radio Bulletin".
Look for how many types of feedback they could put in 1 amplifier in those days. Sounds very good says the author.

[SY]

Besides the usual cathode degeneration and the overall loop, the only "extra" I see is from the output tube plates to the driver cathodes. That's a good idea in pentode output stages.

The designer didn't take advantage of the multiply tapped output transformer secondary to provide cathode feedback for the output tubes.

[kevinkr]

There is also feedback from the secondary of the output transformer, take another look... The way it is drawn makes it less obvious, but it is derived from one of the intermediate output taps. (Seems like this output transformer might be able to do balanced 600 ohm and some other odd things, I think that tap might be the 8 ohm tap.)

Take a look at the Citation II schematic, there are several loops in that design as well. (Early 1960's) The Citation II actually is a very good sounding amplifier, and that from a guy who is avowedly a single ended devotee..

[Jaap]

here another unusual design from 1966 in the same magazine. Nice to try those feedback options.

[SY]

There is also feedback from the secondary of the output transformer, take another look...

That's what I meant by "overall loop." Sorry, didn't mean to be cryptic.

[Yvesm]

Originally posted by Jaap
here another unusual design from 1966 in the same magazine. Nice to try those feedback options.

An interresting way to balance DC in the Push Pull.

Yves.