Envelope generator

MICRORACK Modules
1

Envelope generator allow to produce envelope signal from gate or trigger.
It has two working modes: attack/decay (sustain LED is off) and attack/release (sustain LED is on).

urack_modules-Envelope Generator.drawio
Image of the latest released version of the module. This is not the final product, development is in progress.

In attack/decay mode any trigger or gate on gate input produce one-shot sequence of attack and decay. You can control attack and decay time by knobs and by external CV from 5 millisecond to 30 second.

urack_modules-Envelope Generator_ad
End of cycle (EOC) output produce trigger pulse at the end of attack + decay sequence. You can make LFO from envelope generator by connecting EOC to the gate input, so on each end of cycle generator will start cycle again.

In attack/release mode when gate is switched on, output is slowly rise till get the input level. When gate is switched off output is slowly fall to zero.

Mode changing button also trigger the envelope manually when is switched from A/R to A/D mode.

urack_modules-Envelope Generator_ar

So envelope generator works as slew limiter. If input signal is not binary level gate but CV changing from 0 to 5V, envelope generator smoothly follows input signal.

urack_modules-Envelope Generator_slew

Also if you set fall time more than rise time and pass audio signal to the gate in, envelope generator will work as the envelope follower

urack_modules-Envelope Generator_follow

Known issues

  • rise and fall time is in wrong range
  • rise time knob is inverted
  • board outline and pcb color marking update is needed
2

Cv inputs for rise and fall with the ability to to loop the evolope :pinched_fingers: question is how fast can this thing go?! :smirk:

Also something like this would be a great teaching point. I remember the first time i came across “end of cycle trigger” didn’t have a clue for months what that was typically used for as id been accustomed to having a switch or button simply labelled “loop”. Then i quickly realised damn this isn’t just a fun new flexible modulation sorce but its also a whole new sound source as well! I think its things like this people miss out on

3

We have issue with time range right now, but the range can be fixed by tuning of the resistor values. I plan to implement rise/fall time from about 30 second up to 0.005 second (200 Hz), so you can use this module as LFO and even as signal oscillator

1 Like
4

Hooray, big description update!

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Wow, this is a flexible module!
At first I didn’t think much of it: one of those simplified envelopes, where you need two of them to build an ADSR. But often a two-stage envelope ist sufficient, and this analog gate input opens up so many more uses!

Versatility of the modules is what distinguishes a modular system from a sawed-apart monosynth. :wink:

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I was inspired by Buchla envelope, Makenoise Function and another same ad/ar envelopes