Realistic Moog Concertmate MG-1

via this auction

"Realistic Moog Concertmate MG-1 with the following upgrades:

1/4"-Jack audio output (see photos below)
1/4"-Jack audio input to 24-dB Moog filter (see photos below)
Improved gate response
Multitrigger & continuous glide
Octave pitch drop
MIDI2CV - Design: Bojan Burkeljc
MIDI Notes - Pitch Voltage & Gate Trigger
Pitch/Gate source select switch (MIDI or Keyboard)
Sticky black foam removed

These modifications transform the existing MG-1 into a responsive and controllable analog monosynth with a lush Moog ladder-filter. To the left of the keyboard, there is a switch to select between MIDI control or internal keyboard control. With MIDI control selected, the pitch voltage and gate trigger are controlled by the MIDI interface. The board converts MIDI data from note on/off messages to a pitch voltage and a gate trigger.

The filter input and the MG-1 audio output are routed through 1/4" jacks that take the place of the pitch and trigger jacks. The jacks are unlabeled in order to preserve the original aesthetics as best as possible. The filter input can be mixed with the MG-1's audio sources (2 VCOs, Noise, Bell, and Poly).

The improved gate response affects the internal keyboard gate and allows for faster playing (quicker successions of triggered notes). The multitrigger modification also improves play of the internal keyboard. It restores Moog's typical low-note priority, retriggers when you play a new note and release a note to return to the original note. It also adds continuous glide, such that the glide will not stop in-between notes (and off-pitch) if you take your hands off the keys, the pitch will continue to glide to the note you played."