I came across this beautiful thing
But i what i would love to do is use an audio signal rather than a modular one.
i would love to use it in this kind of chain
drone synth 
simple envelope generator delay pedal
does any one know how i could mod this build to take a line level signal.
Sounds like what you want is an envelope follower. Control voltage, which is what this circuit is meant for, is fundamentally different from an audio signal. What are you wanting it to do with the drone synth? If you are looking to alter the volume according to a triggered envelope, then this one plus a VCA is what you want, but you need a way to trigger it. If you don’t have a trigger sequencer, you’d need to build the version that has a button so you can trigger it manually.
this is correct Christian thanks for your reply!
I basically want a transform mute button like the ones i remember seeing on old Gemini mixers but with the added control of attack and decay
So then is the drone synth audio being fed into the vca and the Envelope generator controls the vca?
That is exactly right!
Yes, you feed the
Audio to the “VCA” Audio IN,
A Triger to Gate IN on the “AR” Generator
EnvOut to the “VCA” CV IN
So when you activate Gate IN, the Envelope generator begins to increase the output voltage going to the CV In on the VCA and thus increasng the amplification.
Rob
