PolyKit Duo is a DIY Juno-style polyphonic analog Synthesizer

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PolyKit Duo by Craig Barnes is a DIY Juno-style polyphonic analog Synthesizer based on analog circuitry controlled by Raspberry Pi’s.

You don’t have to buy a polyphonic analog synthesizer off the shelf in a music store. You can also build one yourself. It will take a long time but you can say that you have built something of your own.

Craig Barnes has created an exciting DIY project called PolyKit Duo, which can be found on Github.

PolyKit Duo Synthesizer

PolyKit Duo

Two years ago, Craig Barnes released the PolyKit Duo on Github, a 6-voice analog Synthesizer. The synth is based on a mix of analog circuitry and digital control. It is based on the PolyKit DCO and PolyKit-X-voice board projects by Jan Knipper. 

However, Craig has taken Jan’s design further and expanded it into a fully programmable six voice DCO-based Synthesizer. The sound is analog, but there is a dual Raspberry Pi Picos (each for $4) in the core that takes over the digital control

PolyKit Duo

The synth is comparable to a Juno 106 combined with a Crumar Bit 01 rack unit but with full control.

PolyKit Duo features two DCOs with sawtooth and PWM waveforms with independent mixing options. According to the developers, they are similar in design to the legendary Roland Juno series.

Then, it has multiple filters based on the vintage Oberheim Matrix 12. I don’t know if they are also analog. I will add this when I find the information. The Github document says that there are eight different filter configurations available.

On the modulation side, it has two LFOs, where one is a sinewave LFO for the PWM, and the second has 16 waveforms for the entire synth. The synth also has ADSR envelopes with looping functionality and selectable log/lin characteristics. It also has a Juno-60-style analog chorus built in.

Velocity and aftertouch control are also available in the synth. You can route the velocity to the filters and amps while the aftertouch control is routable to the DCO LFO depth, filter LFO depth and filter cutoff.

PolyKit Duo also offers patch memory in up to 999 memory locations and full MIDI support via in/out/thru sockets.

First Impression

A lovely project with which you can build a 6-voice poly analog synth. For people who like to build everything themselves, this project might be worth a look.

PolyKit Duo is open-source and available on GitHub. 

More information here: GitHub 

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  1. Craig is crazy. Check his Facebook. Sitting in Ukraine and building mad machines. You find him in the Synth-DIY Group on FB. He also shows the whole process of development

  2. Read int 5he schematic the filter is analog, based on the 3372 cem chipmsame as the matrix-12 filter

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