Cmos noise bell

For those interested, a super simple, but effective module, a panel of hyper diversified metalic sounds (hit, snare, bell …)

Only 2 out of 4 oscillators have a pitch setting (lack of space on this module), the other 2 have a trimmer, but a switch allows you to go from 2 oscillators to 4.

the link schematic


Reprazent da HAD! That Logic Noise series is a great intermediate step for anyone looking to go beyond the one-transistor oscillator that occupies so much of this board. Now I can’t find the thread with the cymbal I made from roughly the same circuit.


the Cymbal is at the bottom of the link I posted :wink:

The inspiration for this circuit is the fantastic Synbal project from “Electronics & Music Maker” magazine in 1983.

So by pure coincidence, today’s mail contained, among many other things, a mini module with the noise and “metallic voicing” sections from the Synbal.

I guess I should have posted this to the mail thread before I started building, but I’ve been optimizing my build process lately and got a bit carried away :smiley: (need to do some tests before I populate the noise section)

EDIT1: It works! The tuning voltage range is larger than expected, though, so something’s not working as expected. Or I cannot math. Probably the latter.

EDIT2: Oops, the noise generator has a “have you tried turning it off and on again” issue. Stupid capacitor left behind from an earlier iteration (one more thing for the checklist, I guess). Bodged on an extra resistor, and now all’s well (need to tweak some levels, though).


Where did you get that LMNC MS-20 I see lurking in the background there?

It’s basically Sam’s stripboard, but as a small PCB in that silly form factor (and colour) I’m using for my builds.

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