The Benjolin...

[lemonhorse]

The Benjolin is a ‘noise box’ that is ‘bent by design’, meaning that it always has a definite amount of unpredictability while it is still intuitive to play. The Benjolin features two eighteen-octave range voltage controlled oscillators that drive a ‘rungler’ circuit, circuitry that in essence uses a special interference technique feeding back into the oscillators to force them into wild chaotic behaviour.
http://web.me.com/klangbureau/DIY/Benjolin.html

[lemonhorse]

Benjolin synth project - intuitive, unpredictable, fun at parties
http://blog.makezine.com/archive/2010/02/sonic_revelry_of_the_benjolin_light.html

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The Benjolin schematic to download as pdf
http://electro-music.com/forum/viewtopic.php?t=38081