Module A-171-2 is a voltage controlled slew limiter with a lot of additional features beyond a simple slew limiter. It's mostly a licensed copy of Ken Stones VCS which is in turn based on the Serge VCS.

Typical applications:

- VC Slew Limiter / VC Portamento / VC Low Pass Gate:

Cycle switch = off, no trigger signal applied to Trig socket: Voltage controlled Slew limiter or portamento generator: the signal applied to the signal input is "slewed". The slew up and down times are controlled manually by means of the Up and Down controls, the effect of the CV Up and CV Down control voltages are controlled by the CV Up and CV Down controls, in exponential mode these controls also affect the slew shape (see symbols at the CCW and CW positions of the controls).

If an audio signal is applied an short slew rates are chosen the module works as a simple VCF / VCA combo.

- A / D Envelope Generator / Pulse Delay / Subharmonic Generator:

Cycle switch = off, trigger signal applied to Trig socket, no input signal: Simple Attack / Decay envelope Generator, the rise and fall times are controlled like the slew up / down times above, including the shape of the falling / rising slope of the envelope, the exp. CV input can be used to change both attack and decay simultaneously.

At the End output a pulse appears as the end of the envelope is reached (less than about 20mV), this can be used as a pulse delay.

If a series of triggers are applied to the VCS faster than the total rise and fall times, the module will divide the incoming signal by a whole number. In the audio range the output will be the sub-harmonic series.

- VCLFO / VCO:

Cycle switch = on, no trigger signal applied to Trig socket, no input signal: Voltage controlled LFO / VCO, the rise and fall times of the waveform are controlled like the slew up / down times above, including the shape of the falling / rising slope
the exp. CV input can be used like the CV input of a VCO or VCLFO, the response is exponential but not exactly 1V / oct.