AJH Synth have had quite a few requests for a variant of MiniMod contour generator with Release added to the envelope so that it is full ADSR but still with the characteristics of the Model D – so this is what they have done!
The DH-ADSR is exactly the same circuit as the original Model D envelope and therefore features the same contour shape and retrigger behaviour, but with the addition of a release control. However, they have also added a pulse delay and pulse stretch circuit, along with a re-trigger facility (both of these can be switched out of circuit so that the envelope is a simple ADSR unit).
The addition of pulse stretching and retrigger makes it into an LFO module and it can perform in a similar way to the EMS Synthi A and VCS3 Trapezoid generator, with a variable delay between each trigger and a variable “on” time – however it can also have full ADSR envelope on each retrigger too!
- PREDELAY – This control determines how long (up to 10 seconds) the start of the envelope is held off, after a gate is received. This ability to delay the onset of the envelope is especially useful when used in conjunction with a standard ADSR: With both envelopes receiving the gate simultaneously complex envelopes can be produced as the DH-ADSR only starts running through its stages after the standard ADSR has completed. Once their outputs are mixed together in a mixer a single evolving envelope with multiple stages is produced!
- Use of the bipolar mixer found in the MINIMOD CV MIX-OFFSET-VCA module can enhance this technique even further, with more precise control over the polarity/offset of the envelope mix possible. Using the VCA of this module could allow for external modulation over either/both of the signals. It goes on…
- HOLD – When in Del-Hold mode (switch down) the HOLD control determines the gate length applied to the envelope, and thus controlling its length/overall shape. When the switch is up, normal ADSR action is produced.
- RETRIG – In this mode the DH-ADSR becomes an LFO, which can mimic the “Trapezoid” function of the vintage EMS designs. HOLD controls the length of the trapezoid shape, and PREDELAY allows for adjustable gaps between each repeat of the shape produced