Hi all, I posted this in the live sound/instruments forum but didn't get any response so I thought I try again here 
This is the reverb drive and recovery system I have built:
[IMGDEAD]http://www.swtpc.com/mholley/PopularElectronics/Jan1968/PE_Jan_1968_pg42.jpg[/IMGDEAD]
I would like add a feedback control knob into the system for some controlled ringing/feedback.
The Doepfer A-199 Spring reverb has one but I'm not sure if/how I could get a similar result. Here's a video of the A-199 feedback control in action:
https://youtu.be/Ujw3NB5BYqg?t=8m34s
I have tried a few different methods, one of which sort of worked but ended up in uncontrollable screeching. Other methods also produced scary results or just added a little unwanted noise.
Is it possible to achieve what I'm looking for with this system? As space in the enclosure is an issue, I'm looking to do it with a single pot.
Thank you

This is the reverb drive and recovery system I have built:
[IMGDEAD]http://www.swtpc.com/mholley/PopularElectronics/Jan1968/PE_Jan_1968_pg42.jpg[/IMGDEAD]
I would like add a feedback control knob into the system for some controlled ringing/feedback.
The Doepfer A-199 Spring reverb has one but I'm not sure if/how I could get a similar result. Here's a video of the A-199 feedback control in action:
https://youtu.be/Ujw3NB5BYqg?t=8m34s
I have tried a few different methods, one of which sort of worked but ended up in uncontrollable screeching. Other methods also produced scary results or just added a little unwanted noise.
Is it possible to achieve what I'm looking for with this system? As space in the enclosure is an issue, I'm looking to do it with a single pot.
Thank you