Noisegen

The simplest and purest way to sonify a semiconducting crystal, the noise generator isolates the fluctuations in current passing over the crystal. As the resistance of minerals and samples vary, the potentiometer, RV1 allows you to set the bias for the transistor to tune it to different materials. The output requires further amplification to convert it from a fluctuating current to a voltage. This stage will be integrated in future versions, but it's nice to have such a simple circuit. Originally built with an opamp, the transistor provides a simpler approach which seemed to work more reliably with a wider range of semiconducting material.

It can provide the simplest approach to listening to the difference between different minerals from different localities.