Aries AR-312
Envelope Generator

Aries modules were available both as kits and factory modules.  This module sold in 1975 for $49.50 in kit or $99.00 assembled and raised slightly in 1977 to $61.00 in kit or $110.00 assembled.  This module appear to be a kit due to the build and solder quality.



I combined specifications and schematics from Robert Leiner (with permission) and my photos into a PDF document.  Note that R31 has been corrected in the schematics connecting to -15V instead of ground.

AR-312 Envelope Generator Document

Aries AR-312 Documentation (compliments of Michael Gilbert)


I have not been able to find PCB layout information but this is a pretty simple design and both sides of the PCB are easily accessible.


The PCB is a single sided tin with no solder mask.  Care is required when doing repairs as the pads do lift easily.


The AR-312 EG operates with 10V trigger and gate inputs but I modified the circuit to operate with 5V inputs by changing R4 to 20K and C4 to 0.1 F.


This scope image shows the minimum attack and release times.  Note that the release cycle does not start until the trailing edge of trigger as shown by the flatted portion between attack and release.


The measured minimum and maximum delay times for each phase is:

Minimum Time Maximum Time
Measured Specified Measured Specified
Attack 3.5 mS 2 mS 5.8 Sec 4 Sec
Decay 8.8 mS 2 mS 8.8 Sec 2 Sec
Release 5.0 mS 2 mS 6.0 Sec 2 Sec