I found 3 schematics online that got my attention and i wanted your opinion about these circuits. Are they suitable for testing or do they show any major faults? Wasn't able to get in touch with the designer so no help there..
Vari Mu compressor (it isn't clear to me where the tubes should get their voltage from)
opto type compressor
some kind of solid state pultec style equalizer:
Vari Mu compressor (it isn't clear to me where the tubes should get their voltage from)
opto type compressor
some kind of solid state pultec style equalizer: