I’m here to tell you that if you have a sudden desire for a simple AR envelope generator, you can build one quickly and easily. Or you can do what I did.
Kosmodrome now has most of the basics, but it lacks an envelope generator. I have an ADSR planned. Planned is quite distinct from assembled and working. I need parts for it, so even if I wanted to do it on stripboard with a homemade front panel (and I don’t) I couldn’t, not yet.
So I figured as an interim thing, I’d throw together a quick and dirty AR. What could go wrong?
The good news is, I didn’t fry anything. There was no smoke. I chose my mistakes carefully, I guess.
After enough dumbassery to earn me a cabinet slot in the next Trump administration I got it working. Put jacks and pots on an old reject panel but obviously this isn’t going to be mounted in a case in this form.
Apologies for the hilarious wire colors on the jacks, those were from back in my youth.
The circuit’s basically Cory Torpin’s stripped-down k25 EG, stripped down even further. No inverted output, no LED. Turns out I could have stripped it down still more — I populated the -12 V diode and capacitor before realizing the circuit wouldn’t use -12 V.
Not much point in a Github repository, but here’s the schematic — click to enlarge:
Analog Output 
Hey, I was just wondering how this worked in comparison to the very similar LMNC attack release bare bones circuit, which uses a dual supply tl072 but a diode on output – the diode causes a delay in output, and it swings negative for a few seconds after release, which affects re-triggering. Sometimes it starts from -2v rather than 0v, which adds to the delay.
I’m hoping this would resolve those two issues.
LikeLike
Yeah, exactly — that circuit has those problems which this one does not.
LikeLike
Awesome, I’ll get it built! Thanks!
LikeLike