Atari Punk Console With CV/Gate Inputs

The Atari Punk Console (sometimes called an APC) is a simple synthesizer designed in 1980. Back then it was known simply as “Sound Synthesizer”, and then in 1984 as the Stepped Tone Generator, but in modern times has been renamed again on account of its nostalgia inducing, retro lo-fi sounds.

I worked from the schematic from the Wikipedia page, and added a few bells and whistles of my own, like control voltage and gate inputs so that I can control the instrument from other external devices. I designed the circuit board layout using software called DIY Layout Creator (http://bancika.github.io/diy-layout-creator).

The APC uses two 555 timers, and very few other parts. The outboard hardware actually makes up the majority of this build. The first 555 is set up as an astable oscillator outputting a square wave which triggers the second 555 in monostable mode where it gets sent to the output. The two potentiometers are used to modulate the frequency of the first 555 and the pulse width of the second 555, producing some interesting sci-fi sounds when both are modulated at the same time.

This is one of the easiest synthesizers to build, but very satisfying, and a great place for beginners to start experimenting.

Bill of Materials:
2x 1K Resistor
2x 555 Timer IC
1x 10uf Capacitor
1x 0.1uf Capacitor
1x 0.01uf Capacitor
1x LED
1x SPDT Switch
2x 100k Linear Potentiometer
3x 6.5mm T/S Jack
1x 2.5mm DC Power Jack
1x Stripboard
1x Enclosure