Hand-built and bespoke Eurorack

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'Old style' AVR-VCO mainboard.
York Modular

'Old style' AVR-VCO mainboard.

Regular price £14.99 £0.00 Unit price per
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IMPORTANT: these boards are supplied as-is - they will require some additional work in order to be usable (hooking up inputs and outputs, providing power etc.)

These were what the AVR VCO used before I finally got the hang of hacking on the ATTiny chips - whilst the larger ATMega MCUs worked fine, using a 28-pin IC on something which required 8 pins at most was overkill.

They were fitted with either an Atmega 168 or 328, depending on what I had to hand at the time - this board connected to a front panel via a 5-pin header: 3 inputs, connected to the MCU's analogue pins, an output (filtered PWM) and ground. Inputs could handle 12v but the microcontroller only 'saw' voltages between 0-5V. A fine-tune trimmer was also added.

Despite having a 5-pin Eurorack connector, these boards didn't use the -12V line, and regulated 12V down to 5V to stop the MCU from releasing magic smoke - this means that it'd be quite feasible to run them off a 9V battery.

They'll be sold as-is, with the VCO firmware pre-flashed - the source for the firmware has a permissive license and you're encouraged to hack on it - there's even an ICSP header on board.

You can get the source and board schematic from here: https://bitbucket.org/yorkmodular/avr-vco/src/master/