VC ADSR

Voltage controlled ADSR

This is a somewhat lazy design, but a nice easy build. Basically grabbed the classic Jacky/Kirschman 555 ADSR circuit from 1980 and replaced the pots for Attack, Decay and Release with LDRs inside black boxes (BBX). Not sure why it hasn’t been done before, it is a simple circuit and the results are fun; lots of wobbly, evolving envelopes.

The envelope will start with a signal on the gate or trigger inputs, tho best to send a gate to the gate input and another signal to the trigger input to re-trigger the envelope.

The CVs work to increase the brightness of the LED, which reduces the resistance of the LDRs making the function times shorter. For example; the higher the voltage of a CV on the attack CV input, the shorter the attack time. How effective this is also depends on the setting of the preset pots.

https://www.nonlinearcircuits.com/modules/vc-adsr