Floating paraphase again

[catalin gramada]

There is a clear issue using floating paraphase to drive heavy loads as the signals appears very unbalanced. Different output impedances counts. What is the best way to cure:1. a build out resistor or 2. to modify the feedback resistor value in plate follower, please? Thank you.

[Jon Snell]

Are we talking valve or solid state?
A schematic would help.

[Chuck H]

There is a clear issue using floating paraphase to drive heavy loads as the signals appears very unbalanced. Different output impedances counts.

Any imbalance should be correctable at the divider from the output of the first stage to the input of the second stage. I don't understand why there should be different output impedances. Assuming we're talking about a tube circuit all the paraphase inverters I've seen use a shared cathode circuit and equal plate loads.

EDIT: I guess I'm confused. I don't know what exactly the "feedback resistor" at the "plate follower" would be. I'm thinking you're talking about the divider I mentioned above? I guess if there IS a feedback resistor the possibility of impedance imbalance does exist. As Jon said, a schematic will help.

[catalin gramada]

Here we go
tube is a 6sn7. Measured voltage gain in actual circuit: 15.5.

[Jon Snell]

This design was tried and tested back in 1958. Doesn't perform badly from all accounts;

66 and 22uF are a bit exessive for coupling capacitors don't you think?

[catalin gramada]

This design was tried and tested back in 1958. Doesn't perform badly from all accounts;

66 and 22uF are a bit exessive for coupling capacitors don't you think?

Thanks. There are 22nF and 66nF for outputs couplings (3x22 nF in parallel)

[Helmholtz]

This is a s.c. "self-balancing" paraphase using NFB from plate to grid at the second triode.
The NFB lowers the output impedance of the second triode.