4U021 - Programmer/Sequencer

4U021 - Programmer/Sequencer

The Programmer/Sequencer is a Serge inspired multi-stage sequencer.
Unlike most sequencers, this one makes no use of binary counters, rather,
it uses a set of individual stages, each one directly accessible.
As such it could be considered to allow "random access".

The first sequencer produced by Serge was a 4017 based counter that put out gate pulses.
In order to get a control voltage sequencer, the gate outputs were fed to the input stages of a multi-state programmer.
Usually built in groups of four, but sometimes coupled through a switch, these programmers would only allow a single stage to be active at any time,
outputting the corresponding control voltages to their bussed output jacks.
The stages could be selected either via a gate/trigger input or a panel mounted push button.

This module replicates the programmer, but with one major exception - up and down inputs allow it to be sequenced without connection to an external gate source.
Any stage can be activated at any time by a direct pulse or button press.
Up or down pulses will then step it from that stage.
To limit the number of steps in the sequence, the pulse (gate) output of a stage is simply routed to the external pulse input for the first stage of the sequence.
Note that the first stage used in a sequence need not be the first stage on the panel. For example it would be possible to have the first few stages used as an "introduction", with the sequence automatically looping to a stage in the middle of the panel once the sequence's first run was completed.

The complete sets consist of 2 PCBs, one is the "brain", a smaller board and one large "stage" board, with 16 stages.

PCB:
1.6 mm thick, double sided, green
base material FR4-Standard TG 135-140
surface finish HASL
part values are silkscreened

Front panel
1.6 mm thick soft aluminium (easy to drill extra holes)
17" x 175 mm
10 mounting holes - 3.5 mm, follows the LW specification (top and bottom)
black front, bare/nature back

You can also find 9mm potentiometers at the shop:
https://4ushop.eu/products/b100k-9mm-pot

And nice quality knobs as well:
https://4ushop.eu/products/1900h-clone-knobs

no parts, just the PCB and LW format front panel
Documentation (schematic, bom, wiring)