Dual Low Pass Gate

This module is passive, requiring no power.
Ins/outs: -Audio input. -CV input. -Audio output.
~~~~Circuit Function~~~~
-The audio input sees a light dependent resistor.
-This LDR is optically coupled to a green LED - which is
driven by the CV input.
As the current into the LED increases, LDR resistance drops, the filter cutoff ascends, and signal attenuation is reduced.-Amplitude and filter cutoff are coupled to one another Creating a more organic decay quality:
Intensity control, adjusts current into the LED - The same is true for the trim control, which is meant to set a baseline.
-There is a 4x4 Capacitor bank, with selections via a dip switch, for each section. This allows selection between 15 different capacitance values for the low pass filter ~ as well, when all switches are null, the circuit acts as an optical
attenuator.
Capacitor values are staggered, to ensure a lack of redundancy through the various combinations - and a range that extends by more than an order of magnitude.
with a schottky.
***For the CV input - The LED is protected from reverse bias,
CV input accepts 0v-10v.

https://www.etsy.com/listing/4574720325/linguaedevices-passive-lowpass-gate-4hp