Looping ADSR with integral VCA
Two outputs are provided, one, labeled ADSR, is the raw output of the core ADSR generator. The other, VCA OUT, is the output of the integral VCA. This highly useful circuit implementation hardwires the ADSR generator to the control input of the VCA. The signal at the VCA's signal input, the VCA IN socket, will then be multiplied by the ADSR waveform. You can use any signal into this input, audio or CV. If you use CV, then the ADSR output level will be governed by the level of the CV. If you use audio, then the ADSR waveform will control the volume of that audio signal.
A typical use would have the IN socket being driven by the velocity CV from a midi-CV converter. Thus the harder you hit the keys, the greater the ADSR output level. If you use this to control a filter sweep, this can create brilliantly effective touch sensitivity to your patch.
The circuit is configured so that if nothing is plugged into the IN socket, the VCA OUT will behave the same as the raw ADSR output.
The ADSR is operated by a gate signal, but can also be triggered by slow rising CVs
Also on this module is an LED. This gives a visual indication of the output level of the internal ADSR waveform.
The Oakley ADSR/VCA incorporates a looping mode. Looping means that the output will rise to the attack peak at the speed determined by the attack pot and then fall to 0.6V at the speed determined by the Decay pot. It will then rise again to attack peak and then fall back to 0.6V and so on.
NORM - the module behaves as a standard ADSR.
GATED - the output will loop only when gate is high. As soon as gate arrives the output will rise up at the attack speed and then decay at the decay time and repeat. If the gate is removed at any point the output will then fall at the release time.
LOOP - The module's output it will loop continuously in AD mode. The Gate input has no effect in Loop mode.
In both looping modes the position of the sustain pot can be used to turn the looping on or off. At values above 10% the looping will stop. This is very useful in the 2U version of the module where the looping can be controlled by an external CV.
Attack times: 0.75 milliseconds to 12 seconds (fast) or 3.75mS to 60 seconds (slow). Charging voltage +15V, internal attack peak +8.2V. Pseudo linear ramp.
Decay/Release times: 1.8mS to 15s (fast) or 9mS to 75 seconds (slow). Time measured from 90% of sustain value to 10% of sustain value. Exponential decay slope.
Sustain levels: 0 to 100%
The attack peak and maximum sustain level is 5V from the ADSR socket.
With no jack plug inserted into the IN socket, the attack peak and maximum sustain level is 5V from the VCA OUT socket.
Available as an assembled Module and as a DIY project.
This Module is currently available.$243 Price in € submitted Oct 26th 2012, 10:03 by Squiggletronics | last Change Apr 3rd 2020, 06:12 by wiggler87830