AM1033 Dual DADSR


AM1033 PCB

Overview This is a replica of the ARP 1033 Dual Envelope Generator module from the ARP 2500 Analog Modular Synthesizer. The module consists of two traditional ADSR envelope generators plus a Gate Delay.

This envelope generator is known for its snappy 1ms fast attack and decays but the longest phase times are only 2 – 3 seconds. There are panel controls to select trigger options, an incandescent “gate on” lamp and a manual gate push button.

AM1033 Module My design uses the same schematic laid out on a large 150 x150mm PCB. 1M Log 1/8″ shaft potentiometers are nearly impossible to locate, but I eventually found some in Mousers catalogue and bought a set, enough for three modules. I was going to use 45mm sliders with ARP style coloured caps, with an Initial Delay control on a rotary pot, maybe later. The module has the following front panel controls for each Envelope Generator:

  • Delay
  • Attack
  • Initial Decay
  • Sustain Level
  • Final Decay
  • Toggle switch for Multiple or Single Trigger
  • Red Incandescent Indicator Lamp for Gate On
  • Manual Gate Push Button

There 10x 3.5mm jack sockets mounted on the rear the panel, for each Envelope Generator we have:

  • Gate
  • Trigger
  • Gate5V
  • Inverted Output
  • Normal Output

Module Build The PCB layout was laid out in September 2006 and then updated for a large 150 x 150 mm PCB in September 2015 (9 years ….). 4x PCB’s were ordered, with the first one as a trial using metal film resistors as I suspect this circuit is going to be tricky to get working. I left the build until February 2016 as I had a backlog of PCB’s to sort out and get working. The circuit works fine, except the JFET pin out was incorrect. Two AM1033 modules were built and completed in 2017.

Copyright AMSynths 2017