AS3310 Voltage Controlled ADSR
Closed Source

AS3310 Voltage Controlled ADSR

Published Mar 2025 · 1 min read

ADSR Envelope Generator Analog

Module GitHub Link

This module is licensed under the MIT License

TODO

  • Schematic
  • Build prototype
  • PCB Design

Introduction

This module is a simple VC ADSR design. The design is based on the chip’s datasheet info.

Module Images

Front

Back Side

Demo

Module Features

Each envelope parameter is CV controllable (Attack, Decay, Sustain, Release)

I/O and Controls

Inputs:

  • Gate input (0-5v, 0-10v)
  • Attack CV input (10vpp)
  • Decay CV input (10vpp)
  • Sustain CV input (10vpp)
  • Release CV input (10vpp)

Output:

  • Envelope output (0-5v)

Controls (knobs):

  • Attack input attenuation knob

  • Attack offset knob (serves as control knob when no input is connected)

  • Decay input attenuation knob

  • Decay offset knob (serves as control knob when no input is connected)

  • Sustain input attenuation knob

  • Sustain offset knob (serves as control knob when no input is connected)

  • Release input attenuation knob

  • Release offset knob (serves as control knob when no input is connected)

Design Notes

The Attack, Decay, and Release CV inputs are inverting mixers.

The sustain circuit is a combination of an inverting mixer and an inverting amp with a gain of 1 to invert it back in phase. A schottky diode clamps the positive voltage to +5v.

Check out the falstad circuit simulation here

Schematic

Schematic

Conclusion

If you’d like to build this module, I have provided a 3D printed front panel file in the repo. I used readily available green perfboard. The components should line up with the perfboard’s holes. The panel was made using benjiaomodular’s europanelmaker.