Each cassette contains a high pitch oscillation. When both cassettes are played through the heterodyner a series of new frequencies are formed. Any tapes can be used as well.
Edition of 10.

$75 US, $85 International, pp.

Based on a tone decoder, this powered heterodyner has its own onboard oscillator that acts as the carrier signal. Any input signal can be used (sound sample above is a bass guitar played through the heterodyner). Edition of 5.

$150 US, $160 International, pp.

Also based on a tone decoder with expanded effects varying from tremelo to frequency modulation. Any input signal can be used
(sound sample above is a bass guitar played through the heterodyner). Edition of 5.

$150 US, $160 International, pp.

One module is a ringing oscillator on an interval timer. The second module is a powered heterodyner.
Edition of 1.

$200 US, $220 International, pp.