Envelope Follower?

[baremountain]

So I'm just now getting into building. I've circuit bent a few things, and abandoned several others along the way. I realized bending all the cheap stuff with SMDs was probably the source of my headache. So I've got a simple PT2399 on a breadboard that I'm gonna work on modding up nice & dirty, a CV amplifier that's being re-planned, and I've got the parts coming for my next project: a crash sync fuzz (a la Your & You're).
I had read up on a cool sounding mod that I'm interested in implementing, but couldn't find an exact schematic for. Basically I want to make an envelope follower/detector circuit. I've got several types of op-amps and a few other ICs either already lying around or being shipped to me, and I think that'd be the core requirement for this little circuit. The envelope follower would in turn change the frequency of the oscillator to coincide with my attacks. Does anyone have a schematic for a simple (seriously, I don't really care if it has a sensitivity adjustment or anything, though that might be cool to add) envelope follower circuit that'd be fine-tuned to passive, single-coil-level volume?

[cherler]

If you checkout the circuit for the Clarinot I think it might have something along the lines of what you're looking for. There's a simple vactrol kind of envelope follower in there modulating the delay time on a PT2399 if I'm not mistaken. It gives you a depth and sensitivity control and it's pretty easy to follow, it's a really good design IMO.

[Nocentelli]

Clarinot (or uglyface) is quick and dirty, you would probably want to split the guitar signal and send clean guitar on to the delay use the 386 just to drive the envelope LED. The meatball envelope section is amazing, and really not that complex The decay control might be great with a delay (don't bother with the attack control) and you can do up sweep or down sweep. I also think you'll need a sensitivity pot for any envelope control.

[baremountain]

Sick, I'll look into these circuits!
Also to my knowledge there's nothing an external pot can do (except add tweakability) that an internal resistor or trim can't do, so you definitely don't need a pot if you find a sweet spot for your guitar's output levels.
Not trying to do a delay FYI, this is to modulate an oscillator (in effect creating a filter sweep of sorts)

[Eric!]

This article was written for envelope filters but it sure isn't restricted to filtering:

http://www.geofex.com/article_folders/e ... cftech.htm

Very excited to see what your crazy mind comes up with!

[baremountain]

Finally getting around to designing this thing, but my purpose has changed.
I think I'm going to make a signal-thru envelope follower that can spit out an envelope or inverted envelope (both 1/8") and an expression signal (1/4"). I'm a little intimidated by reading through all this literature tbh, but I know I just need to wrap my head around what it is I'm actually trying to do.
So far in the abstract, non-designed planning I've got this:
Output CV range = 0-5V
Sensitivity control (voltage dividing pot at the input jack)
Output limiting control (voltage dividing pot at the output jack)
1/8" env out, 1/8" inverted env out (maybe switchable, but ideally together - unity gain thru an inverting op amp would allow both inverted and non-inverted signal to be sent out)
1/4" expression out
Gate out?
Switchable to LFO control instead of envelope

Eric, that article you shared was very enlightening to a lot of the interface side of design principles, but I wish it went a little more in-depth on how to make the envelope follower with the components it listed. I mean, theoretically I could use a MAX1044CPA+ IC that I got to build the Boneshaker EQ section to get the +9v and -9V rails and just copy the Mutron III ECF, but I also don't want to exactly copy something that exists. It's hard for me (no formal background) to figure out the underlying design principles of these things to design something for myself though.

[controlFreak]

also this: http://www.bartonmusicalcircuits.com/gtrin/