The Postman ASR EG

Inverternoiselabs (Hexinverter Électronique/Papernoise/Tsyklon Labs) - Eurorack "The Postman EG" Panel and Control PCB

A super simple quad attack/release (technically, ASR) envelope generator that you can build for your synthesizer

There is a basic and a complex build version, both of which are on the same PCB.

Basic Version
- Four very simple quad attack/release envelopes (0V to approximately 1V less than the supply voltage)
- Four gate inputs, four envelope outs
- Economical and compact design reduces component count and therefore build cost
- Made from commonly available components
Complex Version (adds these features)
- Inverted versions of EG1 and EG3
- Mixed versions of EG1+2 and EG 3+4
- Mix selection switches to select between inverted and non-inverted versions of EG3 and EG1 for mixing
- Mix level controls for EG1 and EG3 levels into the mixed outputs

http://www.hexinverter.net/the-postman/