Touch sensitive noise - cracklebox derivative

[nicolas3141]

Hi all

Recently I have been having fun with touch sensitive noise circuits as a change from the conventional analogue modular type stuff. I have an exhibition up at a local gallery of interactive sculptural works based on these circuits http://auricle.org.nz/

Here is my discrete interpretation of the famous STEIM Cracklebox circuit. Building it from discrete transistors avoids having to source a discontinued chip and also allows for a few enhancements. The component values shown work well with 9-12V supply and reasonably sizeable touch contact plates. The transformer output allows it to feed the balanced inputs on a mixer/PA without hum problems.

Nicolas

[nicolas3141]

Schematic and BOM

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[nicolas3141]

I have just realised the transformer I actually used was 3k:3k. I have listed it differently in the BOM, but 10k would work just fine as well.

[dougseidel]

circuit looks great - thanks for doing the work and sharing!

[nicolas3141]

Here is a new drawing - minor correction to BOM, plus stripboard layout.

Nicolas

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[nicolas3141]

The stripboard layout does not include the offboard connections to the power, audio outs or the touchpoints. Or the 10k resistors leading to the touchpoints (which I just used like wires to the touchplates). Hoping that is straightforward for anyone building to work out for themselves.

Nicolas

[nicolas3141]

Connecting an input signal across TP1 and TP5 works well. Just played a gig that went very well with my two oscillator bleepy machine circuit running through this one to provide 'effects' : )
Will see if I can get hold of the recording.

Nicolas