Maestro Universal Synthesizer USS-1

via this auction
"This is a vintage analog multi-effect that has the following controls:
Waveform (with Intensity slider) a kind of fuzz effect
Filter (with Frequency and Brilliance sliders) envelope filter
Sample/Hold strange step Q filter effect
Phase (with Speed slider) Great sounding too
Envelope (with Attack and Decay sliders) another yet different envelope filter.
Sub-Harmonic (with a Volume slider and sustained or percussive switch) lower octave in quick hit or swell.
then there is also a slider for Sensitivity that works on the Envelope and Sub-Harmonic, basically increasing the volume of the effect compared to the natural sound.

Instrument plugs into the 1/4" furthest from the plug/transformer, closest to goes to the amp. No clue what the middle 2 do, and have never found any info on them."