had time to simulate a new embarrassing version
some might think why?
cause i want to learn and undestand
really don t know if doable or a totally bullshit...
the idea is a mix of the opa version and the standard design for sidechain and meter
the input buffer it s from W.Jung opaBook pag 454 ( diff. line driver ) , used it also for balancing output... don t know if it s an appropriate configuration
symmetry is fine, also the meter driver seems to track better ( 500uA )
i m using 100k for Att and 10M for Rel, i know it s longer but performance seems better, more control, and if you want go back to RM57 values, you have range
the amp out should be a classB, i hope! i wanted to test...
attached also calibration at bjt mirror both fast and slow Att
of course can contain errors, still learning the long way of electronic
simulated each single part before putting together my Frankenstein
believe i will build it if someone can confirm it s doable...