bm - 104 FUZZ-FEEDBACK
“ ... not so sure who made it, what country it was made in, if the circuit is a modified version of something else, or exactly when it was made. So I have a bit of digging to do before I can write a full article. But, I can say with a high amount of confidence that it does predate the BOSS DF-2 Super Feedbacker & Distortion by at least 5 years, ... Probably my favorite aspect of this is that the feedback is set to be triggered by that red momentary switch, so as long as you hold it down, you get feedback in the signal. But what makes this truly unique and special is that the feedback seems to not only stay in tune, but also starts off as a quiet oscillation and then builds in volume and intensity as you hold down the switch. Amazingly it somehow never gets too abrasive and stays musical even at its loudest! “
cred: tonemachinesblog.com/2022/07/fuzz-and-feedback