Simple feedback device

This nasty mono feedback device from amazing machines looks interesting. Any idea on how they accomplished this passive circuit?

it’s a passive mixer with a fixed low pass filter

One potentiometer, maybe one extra resistor and a capacitor.

It works only if you have an instrument with an input and an output of course!

try without the passive filter first. (just a pot)
works with my c64

you can also try using a send path on your mixer for feeding the output back to the input.

Oh very true on the mixer aux send path to accomplish feedback. Nice

It is well known by guitarists. It’s even the figurehead of one of one of the most famous boutique stompbox builders, “Death by Audio”, called “Total Sonic Annihilation” (have you ever heard of the band “A Place to Bury Strangers”? Love them! although I really find that their business looks very much like steal!).

Here’s one schemo in a guitar stompbox format :

Actually in your example, you replace the switches by wires and that’s all…
I’d say that selling it as is requires some guts…

MicMicMan… Have you ever checked out the WhenTheSunHits Blog? My girl’s blog. She’s a big fan of APTBS, and basically runs a blog devoted to shoegaze/that style of stuff. /derail

I’ve been curious as to the specifics of the nastymono for a while now, as well. Nice info guys. Pretty much what I’ve expected. Pot, res., cap… bam. Feedback. The minibrute’s circuit is pretty much the same.

Nice blog, I’ll follow it :slight_smile:

Have you seen this matrix feedback mixer?