PolyKit Duo by Craig Barnes is a DIY Juno-style polyphonic analog synthesizer based on analog circuitry controlled by a Raspberry Pi.
You don't have to buy a polyphonic analog synthesizer from a music store – you can make one yourself. It will take some time, but you'll have something unique to say about it.
Craig Barnes has created an exciting DIY project called PolyKit Duo, which is available on Github.
Polykit Duo
Two years ago, Craig Barnes released PolyKit Duo, a six-voice analog synthesizer on Github. The synth combines analog circuitry and digital control, and is based on the PolyKit DCO and PolyKit-X-voice board projects by Jan Knipper.
But Craig has taken Jean's design further, expanding it into a fully programmable, six-voice DCO-based synthesizer that's analog in sound, but at its core is powered by dual Raspberry Pi Picos ($4 each) that take over digital control.
This synth is comparable to a Juno 106 and Crumar Bit 01 rack unit combined, but with full control.
PolyKit Duo features two DCOs: sawtooth and PWM waveforms with independent mixing options, and according to the developers, its design is similar to the legendary Roland Juno series.
Additionally, it has several filters based on the vintage Oberheim Matrix 12. I'm not sure if these are analog as well. I'll add more info when I find it. The Github documentation says there are 8 different filter configurations available.
On the modulation side there are two LFOs, one sine wave LFO for the PWM and one with 16 waveforms for the whole synth. The synth also has an ADSR envelope with loop functionality and selectable log/lin characteristics. There is also a Juno-60 style analog chorus built in.
Velocity and aftertouch control are also available on the synth: velocity can be routed to the filter and amp, while aftertouch control can be routed to DCO LFO depth, filter LFO depth and filter cutoff.
PolyKit Duo also offers patch memory with up to 999 memory locations and full MIDI support via in/out/thru sockets.
First impression
It's a neat project that lets you build a 6-voice poly analog synth, and for those who want to build everything themselves, this project might be worth a look.
PolyKit Duo is open source and available on GitHub.
More details here: GitHub
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