Handmade Triple NE555 Oscillator for Eurorack Synthesizer

Another project which took more time than expected, but it does a nice job.

The CV in is over- and negative voltage protected, but not 1V/Octave. It still has a good overall pitch control.

It’s possible to make music, but not in the usual way ๐Ÿ™ƒ

I’m using it as drone or raspi synth voice …

There’s some glitchy FMish amplitude modulation going on and i realy like it.

I’ve used some very bright blue LEDs as peak and frequency indicators which lead into a simple passive summing mixer with attenuation.

The root circuit is based on the schematics of Wikipedia with some several adjustments for better frequency response.

My architecture became better and i will avoid panel mounting wiring for sure in the future. But it’s still a mess ๐Ÿคฃ

The accuracy of my panel drilling skills is … I need to work on this ๐Ÿค”

Somehow i became a fan of single sided / single hole coppered blank PCBs with this project …

The parts i’ve been using:

6x100k pots, 1x50k pot (pitch),

1uf caps, 100nf caps (bypass & output),

47uf caps (pitch in)

1k resistors

4,7k resistors for eye cancer bright LEDs