Tuesday, August 22, 2017

Modular Sequencing: 05 - Eight Step Voltage Sequence

Voltages can be sequenced using a counter, too. In this case, a set of eight control voltages scaled sequenced in a regular loop. A gate output allows both a volume envelope to be controlled as well as the pitch of an oscillator or filter.

A 40106 LFO oscillator is used to drive a 4022 counter, The RES pin of the counter is connected to ground, meaning that a loop of eight is counted. Each output Q0 to Q7 of the 4022 is then connected to an LED for visual feedback (displaying when each step is being played) as well as a potentiometer. Each potentiometer sets the voltage for that step, and all eight steps are connected via diodes to the control voltage output. The signal from the 40106 is used as a gate for envelope control.

If a different length of loop is desired, Q1 - Q6 can be connected to RES instead of ground, achieving loop lengths of 2 to 7 steps.