tube VCA compressor?

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I don't have tube knowledge/experience, but single-ended circuits like the one in your linked article would "THUMP" if fast-enough CV would be present - to be useful as a compressor (this circuit would "mix" the DC CV with the actual programme AC). The coupling capacitor at the output of the circuit would filter out the "slow" DC - but the faster transient CV, as present in compressor circuits would get amplified AND translated to the output.

Could be useful as a SLOW leveller, perhaps.
Naively speaking, the "CV input" integration constant (roughly 10K into 1uF) would have to be significantly larger than the differentiation time constant of the output cap...
 
A remote cutoff gain stage is a tube VCA. The CV is used to modify bias, which in turns modifies the transconductance and hence the gain of the stage.
That's how most of the vintage tube compressors operate. They all suffer of a certain degree of CV feedthrough. Most of the developments of variable transconductance compressors concern CV feedthrough and THD optimization.
 
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