SAG emulation Circuit (schematic)

[Steben]

Continuing my bluestate amp, this must work nicely as SAG block.
+20V to Jfet's, +10V to 4049 chips. opamp can be any dual type (preferably high impedance like TL072)
Rectifier is very low crossover type (1mV).

[TELEFUNKON]

what mosfet and diodes are needed, and why high impedance opamp?

[Steben]

what mosfet and diodes are needed, and why high impedance opamp?

Any low signal diode should work. But once chosen they should all be the same, for obvious reasons.
MOSfet should be a power one (power amps), certainly NOT BS170 or 2N7000.

I "Prefer" high impedance. The input is chosen for high impedance, because I don't want to load the circuit I would use it in, where I tap the signal in front of overdriven CMOS chips.

[TELEFUNKON]

I asked, because I always thought the inverting input in such topologies represent a so called virtual ground
and therefore the input impedance would be represented more or less by the series input resistor
in this case the 100 k plus a part of the sensitivity pot but I may be wrong here?

[Steben]

better version.
After some parently discussion I came up with some changes.

[Steben]

By the way: for those who want to try this out as a stand-alone thing: you can swap the 4049 with a single mini-booster/mu-amp. Will have a similar response.