The POLY555 is an alarmingly coloured and brilliant lo-fi synthesizer based on a whole bunch of 555 timer oscillators.
The POLY555 is an analogue square wave synthesizer with 20 notes of polyphony based on the 555 timer chip. The 555 is one of the most popular integrated circuits ever made and is regularly used by synth builders and DIY makers to make all sorts of oscillations for all sorts of applications. For the POLY555 they are being used to generate the sound.
It’s the successor to the OKAY monosynth that Oskitone’s Tommy built a couple of years ago that I’m sure I covered but I can’t seem to find the article. Anyway, it’s built in the same style with a 3D printed enclosure, keys and open-source PCB designs.
There’s a 555 chip for each note and these are displayed fabulously behind plexiglass and light up whenever they are triggered. Tommy says the only reason he went to 20-note polyphony is because 20 of them line up nicely on the PCB. Features include a 3D printed thumbwheel volume control, powers switch and a “pencil stand” where you can jam a pencil to help it stand up. It has no other controls or synthesizer interaction, you have 20 notes and keys to turn them on and off which probably means that it’s not really a synthesizer at all – but it’s a lot of fun.
The blog post goes into lots of nice detail about the design process and how it all came together.
You can buy the whole kit for $75 and you can get it with the 3D printed enclosure or you can print your own.
- Oskitone POLY555 webpage.