Well that's what they say... My gut says no, but you can confirm or deny whether there is merit in linking these two variable with some bench testing. If desirable the variable gain in the cap modulation circuit could perhaps use another VCA to perhaps track a little better (?). But again I'm not sure I would want to do this so tell us how it works out.Crusty wrote:Ah, so I was comparing the JR var-cap to the non-linear cap circuit and stumbled upon where I must have gotten that timing cap/ratio idea:
The above calculations assume a stand-alone RMS
level-detector. When the detector is placed in a feedback
compressor topology, the effective time constant
that results is calculated by taking the level detector’s
stand-alone time constant and dividing it by the compression
ratio. Therefore, if we plan to operate with
a compression ratio of, say, 20:1, we will need to increase
the timing capacitor by a factor of 20. So, for
our design the timing capacitor, C2, becomes 220 uF,
the nearest standard value.
RE: the non-linear cap, I hadn't seen that schematic before but yes some similarities. I probably need to scan in a copy of my old tape NR schematic if I can find it (early '80s). They are basically switching between one fast and one slow time constant based on a threshold step size.
I designed a somewhat more involved variant of that. Mine in addition to switching between slow and "fastest" time constants for severe transient overloads, also provided a level dependent "faster" attack but with same slow release. I was operating in the linear amplitude domain so this may not translate to RMS comps for several reasons.