Based on the EF in the Buchla Easel

This module is based on the EF found in the Buchla Easel. The main differences being a gain pot rather than a hi/lo switch and a comparator stage to give a gate output. The 1/4” jack is connected to the switch of the 3.5mm input jack.

Otherwise this is an easy module to use, plug in a microphone or guitar or whatever, adjust the gain pot so the LED comes on when you speak or play. Patch the outputs to wherever you want.

https://www.nonlinearcircuits.com/modules/p/4hp-envelope-follower