Gain of this schematic
Connect the JFET gate down to 0V to disable the compression that the JFET brings about. As for gain, I can't tell you because the component references as too small to list and ditto the values. But I can say the the lower right-hand op-amp has the answer to the gain it brings about before the compression threshold starts to have its effect.



One error on the circuit - where I've put "shorting this kills compression" - the short should go to 0V not 4.5V.