The Sinclastic Empulatrix envelope has an exponential curve and the time range of the attack and decay phases goes from 50us to 5s (or 3.5 times as long with a different jumper setting). The Gate/Trig switch select if the envelope reacts to the entire gate or just the rising slope which is great for superfast percussive envelopes at minimal attack setting. The HIT button, used for manual fireing of the envelope always generates a gate, no matter which setting the Gate/Trig switch is at.
The output level of the envelope is depending on the gate level and approximately 2x as high as the gate: when the gate is +5V the envelope output will be around 0-10V
The VCA has no CV input but is modulated directly by the envleope. The circuit is not a classic VCA but a so-called "clamp" which clips the signal instead of scaling it. As the envelope decays it will start chopping off the top (and bottom) of the audio waveform.
The module is inspired by the combination of envelope generator and VCA as used in the 808's hi hat section. This circuitry hasn't been exactly cloned; the envelope times have been shortend and some different components have been used.
envelope: gate/trigger input, envelope output
VCA: input, output
3U Eurorack module, 4HP wide, 20mm deep
current draw: 15mA @ +12V and 25mA @ -12V