Mike - contact microphone preamp card for the Music Easel follower-producing a negative envelope corresponding

follower-producing a negative envelope corresponding to the negative peaks of the input audio signal

specially on the white jacks

voltage controlled portamento

The stages could be selected either via a gate/trigger input or a panel mounted push button

From an early catalogue:

Mike - contact microphone preamp card for the Music Easel follower-producing a negative envelope correspondingMike contact microphone preamp card for the Music Easel Mike is a microphone preamp card with a piezo contact mic built into the panel. With Mike, you can bring environmental noise and feedback into your Easel, inspired by the early days of electroacoustic music in Paris and Cologne, and by the contact microphone and phonograph cartridge experiments of John Cage, Gordon Mumma, Robert Ashley and Nicholas Collins. The concept idea is based on Tom