|steve conner||Re: Looky here|
"Do you have any idea what kind of voltage is generated by this rectifier? Are we talking volts or millivolts?"
It's twice the output of the cathodyne stage so probably a few volts at least.
"Could the rectified ac signal be applied to the cathode of an earlier stage to provide compression?"
Maybe. What you described is a feedback compressor as opposed to a feedforward compressor, where the gain control is after the rectifier (like the Gibson circuit) But the feedback type needs more careful design or it could become unstable and start motorboating like crazy.