Available as an assembled Module and as a DIY project.
This Module is currently available.
Triple envelope generator
PCB - US $18
panel - US $20
assembled - US $160
These are AR or AD generators that will fire on a trigger or a gate, giving envelopes up to approx 25 seconds. A single gate to input 1 will fire all 3 envelopes, when nothing is plugged into inputs 2 & 3.
SMD chips and resistors, but a very easy build with minimal components.
http://nonlinearcircuits.blogspot.com/2015/11/triad-triple-envelope-generator.html
2 Users are observing this
These merchants probably sell this module. Huh?