A Virtual Cacophonic Phototron

The Ramsgate Hovercraft is in awe of the Cacophonic Phototron. Having failed to build an electronic device that makes noises anywhere near that horrific we resorted to modelling it in software. The result is version 1 of the Virtual Cacophonic Phototron which works rather satisfactorily and is designed to be operated with the touchpad of the Korg nanoPad2.


The program runs on Linux and needs Jack2. We’ve GPL’d the source code and you’re welcome to download it and tinker with it. To use it just compile and run then use Jack to connect the nanoPad2 MIDI output to the VCP MIDI input and the VCP audio output to a suitable place such as the system audio inputs (L&R). Then just touch the pad to be rewarded (or punished as you might think) with a really unpleasant noise. You can’t really play it, just sort of influence it. Relating to the original, there are three VCOs linked in a ring so the output of one is the control for the next. In the original the amount of control signal is determined by one of three photoresistors; in the software model there are three points on the touchpad (bottom left, top middle and bottom right) that correspond to the photoresistors. When you touch one of these points the associated control signal is blocked; as you move away from it more of it gets through. None of this will help you control the noise it makes.

Here’s what it sounds like (warning: we had to upload it as a WAV file because the audio is so wild that MP3 compression just made a mess of it):

Here’s the source:



The Korg Monotron Duo

monotron-duo-1000x669Korg has taken modules from its classic MS-20 analogue synthesizer and packaged them as a series of pocket-sized, limited function synths with ribbon keyboards. This Monotron Duo was a gift, and what a great one it’s turning out to be. This teeny-tiny synth looks at first glance like a toy, superficially resembling a Stylophone, but it turns out that the circuitry inside really captures some of the MS-20 magic and despite its limited controls it can make some pretty impressive sounds. The Duo comprises two VCOs and a VCF. There is no envelope generator, it’s just on when you touch the little keyboard and off when you don’t. It also has the ability to modulate the frequency of VCO1 with the output of VCO2, which leads to some surprising and useful sounds. The best part is probably the VCF which packs all the punch of the MS-20 VCF and rings just nicely when the Q is wound up. It’s unlikely you’d be able to play much of a tune on the keyboard. It does have a miniature built-in speaker which is useful but of course can’t do justice to the sound, especially the beefy bass that this little gizmo can pump out. So here’s a short demo. The output has been put through the mono-to-stereo converter, a graphic equalizer and a delay/reverb effect.

Monotron Demo