Doepfer A-171-2 Voltage Controlled Slew Processor

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.

These are the most important features:

Manual control of the Slew-Up time

CV control of the Slew-Up time with polarizer

Switch for linear/exponential shape of the rising section of the response curve

Manual control of the Slew-Down time

CV control of the Slew-Down time with polarizer

Switch for linear/exponential shape of the falling section of the response curve

Signal input: the "to-be-slewed" signal

CV Up Input, affected by the CV Up Control and the corresponding exp./lin. switch

CV Down Input, affected by the CV Down Control and the corresponding exp./lin. switch

CV Up and CV Down sockets are normalled

exponential CV input: named "V/Oct" in the original design but as it's not really exactly 1V/Oct we named this input "exp.CV", mainly used for VCLFO/VCO applications in cycle mode or as common exponential control for both up and down times in slew mode

Trigger input: used for envelope generation or retrigger in VCLFO/VCO mode, a pulse at the trigger input will start the envelope or retrigger the VCLFO/VCO

End output: turns high as the output falls below about 20mV, turns low as the outputs goes beyond about 3.5V, in cycle mode a rectangle signal is generated

Cycle on/off switch: when "on" the End output is internally connected to the Trigger Input to generate cyclic signals like an VCLFO/VCO, max. frequency about 2.5kHz/3.5kHz (shape switches lin./exp.), max period about 15s/40s (shape switches lin./exp.)

Output: the signal output of the module

LED display: displays the slew limiter output signal