From the MAKE Flickr pool

Leadtowill posted this detail shot of a rather excellent mod/conversion –

This was a cassette radio. I removed the motor etc and added an input to the amp section of the circuit, mounted a spring and converted the speaker to a driver with a knife – the result is a roomy sounding spring reverb.
Future additions —- a filter and feedback section, maybe make use of the radio section as a white noise generator…

Quite a few interesting works can be viewed in his Electronic and Microtonal Instruments photo set.