small stone - feedback control keeping "color" switch

[Dimitree]

I'd like to add a feedback control to the Small Stone (to increase feedback, not only to decrease).
the "color" switch interacts on the LFO and also on the feedback. I'd retain that switch, both sides, so I can completely remove feedback when engaged.

How should I add the feedback control then?
I guess using a potentiometer wired as voltage divider instead of the existing 3.3K and 4.7K resistors on the feeback path.
This way, the feedback signal could be fully attenuated (but would that load down the wet signal?) or boosted about 2x in respect to the stock setting, while roughly at center it would work as the stock setting.
what do you think?

[Dimitree]

anyone? :-(

[Mark Hammer]

I'd like to add a feedback control to the Small Stone (to increase feedback, not only to decrease).
the "color" switch interacts on the LFO and also on the feedback. I'd retain that switch, both sides, so I can completely remove feedback when engaged.

How should I add the feedback control then?
I guess using a potentiometer wired as voltage divider instead of the existing 3.3K and 4.7K resistors on the feeback path.
This way, the feedback signal could be fully attenuated (but would that load down the wet signal?) or boosted about 2x in respect to the stock setting, while roughly at center it would work as the stock setting.
what do you think?

I think that's almost exactly what I did on a build a decade back.  Or at least that's my vague recollection.  I might have subbed a variable resistance for the 27k fixed resistor.  Either should work.

Note that lifting one end of the 30k mixing resistor that brings dry signal to the mixing node at the output (just before the 0.1uf cap) will get you vibrato.  When you have achieved your increased feedback goal, you'll find that vibrato+feedback gets you an interesting modulated-wah sound.

[Dimitree]

thanks Mark!
replacing that 27K resistor after the voltage divider wouldn't mess with the filter created with the following 0.1 cap? but probably it's below the guitar range.

about the 30K dry mixing resistor, yes I already planned a switch to lift it! thanks