Adding a Feedback Loop - Input/Output out of Phase

[SeaWitch]

I'm trying to add a feedback loop to this Modded Rat build (on a momentary switch):

https://drive.google.com/open?id=1rD4Zu ... c8AqMQNC5m

The usual approach of Effect Output -> Effect Input feedback loop does not seem to work on this circuit. The signal is killed when set up this way...which may mean the input is out of phase with the output...??

So, how can I determine, on this circuit where an “output” on the board is in phase with the input?"

Does anyone have any ideas? I'll do some more experimenting, but if there are any suggestions or knowledge about how to incorporate a feedback loop into this circuit, I'm all ears!

[crochambeau]

Yeah, typically inverted feedback results in a sort of stability. With enough gain inverted paths can be pushed into a feedback mode, but being able to invert polarity on the signal is a nice touch.

I was unable to ogle your link, so I cannot weigh in on what is actually happening, but usually it does not take much to push into a feedback mode if your polarity is uniform. Sticking something like an LPB-1 or other inverting gain cell into the mix may serve to confirm.

[SeaWitch]

OK! I fixed the link, don't know what happened there...

Check it the layout I'm working ffom when you get a chance, and let me know what you think. thanks!!

[crochambeau]

Trying to decipher strip layouts makes my eyes cross (sorry I can't be of more help), but if that LM308 is employed in a non-inverting manner (looks like it is) and there's an inversion going on at the output FET then you have an over-all invert which would result in subtractive feedback.