ADSR exponential envelope generator with range switch (4HP)

PCB/panel sets are still available for the 'old' design - see here.

An updated version of the ADSR module - functionally the same as its predecessor, albeit with a couple of changes. The range switch is now broken out to the faceplate for easy access, and the mainboard is parallel to the faceplate, rather than perpendicular to it - hence it's a lot shallower.

I'm going to call that a win, and it isn't dissimilar to the design that Doepfer use in their EG modules, albeit without the bells and whistles.

In addition, I've 'borrowed' a couple of features from a Rene Schmitz design, specifically: the resistor R13 is optional, but adding it will give the input a bit of hysteresis (the degree of which is governed by the values of R13 - 1MΩ is what I use) which is handy if you're using a slowly changing waveform as a trigger.

Secondly, there's a buffer between the sustain and decay pots which removes any interdependence between the two. It also uses up an otherwise uncommitted op-amp. As built, the two capacitor values are 220nF (good for percussive patches)and 2.2uF (good for pads etc.) 

Supplied as a complete module complete with mounting hardware and a power cable. Panels are fabricated from dark purple, 1.6mm FR4 fibreglass with gold ENIG lattering.

CURRENT DRAW (approx.):

• 20mA (+12)
• 5mA (-12)