Music and Synth DIY

Eurorack, SMD, Synth DIY, Through hole

Turing Machine, Pulses, Vactrol DIY

turing machine

The Music Thing Modular Turing Machine is as ubiquitous in generative Eurorack patches as houseplants are in modular Youtube videos.

I bought the TM and the Pulses expander as kits from Thonk – a quick guesstimate at the pricing meant there really wasn’t much to be gained by sourcing the parts directly.

turing machine
Turing machine kit from Thonk

The Vactrol Mix expander kit was out of stock, so I went with the PCB, but the BOM is all standard stuff & the only thing I didn’t have on hand were the vactrols. These are VTL53Cs – which no-one seems to have in stock. VTL5C1s seem to be twice as expensive, and have a much faster reaction time – which means they might “click” in this application.

I went with these – Silonex NSL-32SR3s. They work fine – the only thing to bear in mind is the dot on this Vactrol denotes the -ve pin of the LED.

The Turing Machine itself is all through-hole, and very straightforward. The Pulses is even simpler – it has a few SMD resistors, but don’t let that put you off if you’ve not done any surface mount boards before. They’re larger than any SMD I’ve built before – not 0805, possibly 1206? – and if you can build the TM itself, you can defintely build this.

The Vactrol Mix is a quick build too – all through hole and nothing challenging.

There are build guides on Thonk, and the Eagle files are on the Music Thing Modular github.

Masking tape for LED positioning