Dual ADSR Manual


The Dual ADSR contains two ADSR (Attack Decay Sustain Release) envelope generators modelled after those found on many classic synthesizers. The envelope gates are normalled so they can be triggered from the same gate source or independently. The cycle switches allow the envelopes to be used as unipolar LFOs.


See the Module Installation Guide for instructions on installing the module in your Eurorack modular system.

Front Panel


The description below describes one of the envelopes. The functionality is identical for both ADSR 1 and ADSR 2 with the exception of the GATE input.


    The gate button is normalled to the GATE input. Pressing and holding the button will activate the envelope in the same way as an incoming gate signal from a keyboard or sequencer. It provides a useful way to test out the envelope settings or to manually to trigger the envelope during performance.
    When in the ON position the end of the decay phase will start the attack phase again.
    This LED is lit when the decay phase of the envelope has completed and remains lit till the next time the attack phase begins. The EOD output gate will also be high at the same time.
    The rate switch selects between three different ranges for the attack, decay, and release times. In FAST mode the maximum time for each stage is approximately 1 second. It is approximately 10 seconds in MED mode, and 1 minute it SLOW mode.
  5. A[TTACK]
    This slider sets the duration of the envelope attack stage. This is the time it takes for the envelope level to go from zero to the maximum level. The duration is nearly zero with the slider at the bottom, and the longest when the slider is at the top. The length of the longest setting is set with the RATE switch.
  6. D[ECAY]
    This slider sets the duration of the envelope decay stage. This is the time it takes for the envelope level to go from the maximum to the sustain level. The length of the longest setting is set with the RATE switch.
  7. S[USTAIN]
    This slider sets the level of the sustain stage. It is 0 V at the bottom and 5 V at the top. I
  8. R[ELEASE]
    This slider sets the duration of the envelope release stage. This is the time it takes the envelope to go from the sustain level back to 0 after the gate is released. The length of the longest setting is set with the RATE switch.
    The brightness of this LED indicates the level of the envelope.

Inputs & Outputs

  1. GATE
    While the gate input is high the envelope moves through its stages until it hits the sustain stage. If at any time the gate goes low the envelope will enter the release stage.
    For ADSR 2 this input is normalled to the input of ADSR 1 so that when no cable is connected the GATE of ADSR 2, a gate signal at ADSR 1 can be used to trigger both envelopes.
    When a trigger is received at this input while the gate is high it resets the envelope back to 0 and starts the attack phase again.
  3. LEVEL
    This input expects a 0 to 5 V signal and controls the overall level of the envelope via a built-in linear VCA. It is normalled to a 5 V source so when nothing is connected the envelope uses its maximum range.
    This is the primary envelope output. The level is from 0 to 5 V.
    This output provides the inverted version of the envelope, from 0 to -5 V.
  6. EOD
    This gate output goes high once the envelope completes the decay phase and remains high until the next attack phase.

Envelope Times

Mode Minimum Attack Time Maximum Attack Time Minimum Decay / Release Time Maximum Decay / Release Time
Fast 0.2 ms 1.5 s 0.6 ms 2.5 s
Medium 1.8 ms 10 s 3.5 ms 10 s
Slow 9.3 ms 60 s 30 ms 60 s

Note: Times are approximate and will vary from unit to unit due to component tolerances.