SCM 140 ADSR
This module is a straight up clone of the ADSR module found it the famous Roland System-100m modular synthesizer from the ’70’s. It consists of 2 identical ADSR generators with a positive and a negative output. I’ve build this some years ago, there are other simpler designs out there, however, it was a really good learning experience.
Images
Schematics
https://github.com/gerb-ster/SCM-140-ADSR
Links
http://www.florian-anwander.de/roland_system100m/
http://www.vintagesynth.com/roland/sys100m.php