SWOOTY: A Prototype hackable DVCO

York Modular (whom I've written about before) is back with another interesting, low cost VCO design. I'm a happy owner of the earlier VCO'84 - a hackable 6HP digital VCO (RRP £44.99); SWOOTY is essentially a deeper, more complex successor.

VCO'84 sounded really nice as a slightly gritty, digital VCO - it was well behaved (with minimal aliasing) and had CV over pitch and waveform. My own excitement came from trying to make it sound intentionally grungy - I used the Arduino IDE to overwrite the basic waveforms in memory (sine, square, saw), replacing them with crude, quantized versions. I even added wholly new waveforms, e.g. an abrasive digital random wave. The module now aliases in spectacular fashion - a secret weapon for gritty bass lines and percussive sounds. But hey, I might put the polite basic waveforms back one day - it's easy enough to do!

Now 8HP, SWOOTY expands on VCO'84; it's based on the same Arduino Nano platform, but provides the user with 3 synth parameters in addition to pitch (VCO'84's only other parameter was the WAVE selection). Developer Simon Ward states:

"One of my limited-run prototype modules - this is what I call my 'VCO development platform'. It has spawned a couple of designs, most notably the 'original' VCO'84.

As well as the usual pitch CV input the board, and thus firmware, is able to support three other 'parameters' - these might be pitch CV for a second 'voice', phase separation, detuning etc. If you can implement it in the firmware then chances are you'll be able to control it from the front panel.

This is definitely what I'd call a tinkerers module, as befits the 'prototype' designation, but there's nothing stopping you using it for just making a racket should you feel the need to.

Eagle-eyed viewers will note that there's an output for the PWM waveform - this is something I've been added to my recent digital VCO designs because, with a bit of careful filtering, you can use the filtered PWM output to generate a whole load of different waveforms and timbres (my FRCL module is handy for this - that'll be making a comeback in a slightly redesigned form)

The build is relatively straightforward - you'll need to source an Arduino Nano (or equivalent) board to host the firmware, but the rest of the components are fairly mundane (pots, resistors, capacitors etc.) and the surface-mount components have been pre-soldered.

The boards are finished in white with black silkscreen and gold ENIG lettering.

You can get the schematic, firmware and whatnot from here: https://github.com/yorkmodular/swooty-dvco - the Gerber files are also provided should you feel the need to fabricate your own modules.

This module is licensed under the Creative Commons license (CC-BY-SA 4.0) which basically means that you can do what you like the with the files providing you give credit where it's due and any derivative works are released under the same license (TL;DR - do what you like, but don't pass it off as your own)

There will only be four of these PCB sets available (the fifth has been built up and is used as a base for firmware development)

If you'd like me to supply an Arduino Nano with the PCB and/or provide a pre-built version then contact me in the first instance - there will be an additional charge for the building and testing."

Tinkerers will, no doubt, have a lot of fun configuring those parameters. What do you imagine? Wavetable scanning? Ringmod? Quantisation? However you like your DVCO's, you can grab a PCB set for £14.99 from here: https://www.yorkmodular.co.uk/products/swooty-prototype-hackable-dvco-pcb-panel-set-8hp

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