The A-170 Dual Slew Limiter consists of two separate slew limiters, also known as portamento controllers or integrators.
In electronics, the slew rate represents the maximum rate of change of a signal at any point in a circuit. Just like a Glide circuitry, it flattens or smoothes the incoming signal.
For precision voltage control this one is recommended, but version One (before May 2009 / check your version number on the module's PCB) had a small voltage drop that was caused by the protection resistor at the A-170 output.
( check Doepfer's solutions for that HERE )
A-170 modules after May 2009 don't have this voltage loss.
The second Slew Limiter has separate controls for rise and fall times, and you can set the overall range (high/low/medium) for these parameters with a three-position switch.
Because the diodes in the lower Slew Limiter are voltage-dependant, there is a voltage off-set of around 0.5 V. This naturally makes it unsuitable for precise 1Volt- per-octave work, but for simple voltage control this is no problem at all.
Not only is the lower Slew Generator suitable for pitch-CV's, you can alternatively use this one as a simple AR (attack/release) envelope generator (works with any gate/trigger or LFO).
Very useful if you don't have enough envelope generators and want some punchy or percussive basslines.
Also worth reading: Wikipedia Current Limiting
Nice piece of info! Just got myself one of these (wanted to be able to play some of these cool solos with gliding notes... :-)
ReplyDeleteMarc JX8P