A true vintage noise gate!
Well, I guess this layout isn't very true to the original design. The original had a TL022 and an LM358 dual opamp which I replaced by the TL074 quad opamp.
The original also had a now obsolete CLM50 optocoupler, which I replaced with the VTL5C10 (D1) as suggested by "Foo Zen Trader". A LED/LDR combination will work too, but may require some tweaking of R14 to get unity gain when the gate is open.
R21 is added as a pulldown resistor in case you want to true bypass it.
I have yet to build this, so it's marked as unverified!
I boosted the input signal by changing R1 to 1M which gave me a better control over the gate. You may need to lower R4 to 110K if the gate won't close at all...
You can also use standard true bypass switching instead of the 'open gate' switch SW1.
Click here to see the bill-of-materials as a list or download it as a comma separated values file (.csv).
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