For a very basic, passive envelope follower, try this. It worked for me, and it's only five components: 2x jacks Diode: 1n4148 Resistor: 100k Capacitor: 1uf Connect a diode between the input and output jacks (the tip connectors), configured to let through positive voltages (= arrow pointing from in to out). Connect the jacks' ground connectors (with wire). Connect the resistor from the output tip to ground, then do the same with the capacitor, from output tip to ground. Voila! I can't do a Moritz Klein breakdown of how it works exactly, but the diode takes only the positive voltages, the capacitor holds it high and smooths it into a cv voltage, and the resistor allows the voltage to slowly drop back down?? That's my guess at least. If you solder this, you don't need stripboard, just solder it right onto the jacks. I found this little schematic in a pdf, "Passive multiples and friends" by North Coast Synthesis Ltd., Matthew Skala - Bonus, so you have something to do with it: Envelope follower sidechain patch: Mult your kick output, send one to this, send the resulting envelope to an inverter/polarizer to invert it, mix with positive offset voltage, and send that to the cv input of a vca, and send a synth or drone or noise through there. The offset keeps it open, and the negative envelope ducks it when the kick hits, for a louder, more powerful kick without adding dB's (to save your eardrums)
Excellent 😎 Looping envelopes are so good. My old Clef Microsynth has that. A lot more versatile than an LFO. Frankly I can't understand why all envelopes don't offer this.
This might be a stupid question, but this circuit is passive, right? I don’t get what the top most bread board jumper from the IC to the positive rail is doing, as the positive rail isn’t connected to anything.
Both opamps need to be powered. Think about it: when the envelope reaches 0v, this circuit sends out a trigger signal. That trigger has a positive voltage, and that voltage needs to come from somewhere. It's not the input because that's at 0v (and there's no capacitor that "saved some for later")
Can't make it work, getting really frustrated. Tried with a bunch of different TL072's, that's not it. Checked my power supply, not it (there actually turned out to be one module making the resistance between ground and -12v very low, like 80ohm. Took it out of my rack but not even sure if that was causing issues anywhere). Checked connections between everything, can't find issues there. The buffer is actually working, but not the trigger. Tried to get three 100k resistors with similar actual resistance, just in case. Double-checked the ic pinout a few times. Early on I did mess up the two inputs on the Schmitt trigger. But now it's working fine. Tried with the IC not powered. Nothing. I'm stumped...
After writing this I looked up to see the trigger finally coming through. What the actual fuck. I didn't do anything. Can't say I didn't learn anything from this experience but I definitely can't tell you what was the problem here in the end. I fear that it'll stop as soon as I touch it hahaha Edit: Turns out the envelope generator I was using doesn't work. My two other EGs (full ADSRs) do cause a trigger to happen, but this AD generator doesn't. I measured the output after it supposedly is at 0v, and it stays just sliiiightly over, unlike the other two that dip slightly in the negative V.
I would love to see more kind-of-expander modules! For this one I'd add a passive OR, to mix the trigger from this with an external trigger because envelopes often only have one input.
Hey Moritz, would you mind if I used your solution in the ADSR projects on my website (with full credit given of course)? I think a lot of people will find it very helpful.
these are the cheapest ones from thomann (sssnake patch cable set) - they‘re 10€ for 6 cables. not the best quality (had one break) but ok for the price!
hello, this short video was awesome :). Could i hyphotetically use the TL074 on this inverter configuration to make the oscillation core on your VCO project instead of the 40106?
Yes, but in practice, the slew rate of the opamp is a little low... This doesn't matter a whole lot at low frequnecies, but the higher you go, the more of an impact it has. There are likely better opamps out there for the task, and with them, this is likely a perfectly viable option.
If I am not mistaken, the output will be a really short pulse (enough to raise the envelope above 8V), basically only triggering the Attack and Release phases. This seems to be the case as the S and D knobs don't really seem to do much in your sound example. Also, I would guess that the envelope will then swing between 4V and 8V.
So is this diagram the wiring behind the scenes (the directions of the arrows are throwing me off a bit)? Meaning the output of the envelope is wired to the trigger input such that when the input returns to 0v, it starts the cycle again? Is the "5(S?)/V" switch in-line to toggle between looping and one-shot behavior?
Der Schaltplan in der Form ist falsch und es wird so nicht funktionieren. Seit wann ist der Ausgang vom OPV zum Eingang geworden? Nächstes mal um die Menschen nicht zu irritieren, tue bitte nicht falsche Informationen zu verbreiten.
