"A virtual analog synthesizer inspired by the classic Roland Juno polysynths, with DSP calibrated from hardware measurements, firmware analysis, and factory schematics. 6-voice polyphonic.
Free and open source. AU, VST3, CLAP, LV2, and standalone."
Additional details via Reddit:
"We started building a Juno software synth in a Brooklyn loft in 2000. 25 years later, we're releasing it as open source. Meet the Ultramaster KR-106.
Back in 2000, my buddy Dave and I started Ultramaster Group with a wild idea: professional audio software for Linux. We were young, broke, working in a loft in Brooklyn, and perhaps a little bit ahead of our time.
Life happened. I went on to start a screen printing studio. Dave ended up at Google. But we never really stopped thinking about the synth.
Fast forward 25 years. Hardware is exponentially faster, DSP methodology has evolved, and we now have access to oscilloscopes, service manuals, and communities like this one. So we went back to the source code and overhauled everything.
The KR-106 is a 6-voice polyphonic Juno-106 emulation with:
Per-voice DCO, VCF (TPT cascade, IR3109 OTA-C design with 2x oversampling), VCA, and ADSR
Sub-oscillator (CD4013 flip-flop model) and noise source (2SC945 avalanche model)
PWM modes (manual / LFO / envelope)
4-position HPF (bass boost / flat / 240 Hz / 720 Hz)
Per-voice component variance modeling analog tolerances (pitch ±3¢, envelope ±8%, VCA ±0.5 dB, pulse width)
BBD chorus emulation (MN3009 modeled with Hermite interpolation)
Arpeggiator, portamento, Mono/Poly I/Poly II key modes
Two calibration modes: '1984 Mode' (firmware + schematics) and '1982 Mode' (circuit analysis + hardware measurements from my own Juno-6)
128 factory presets decoded from original SYSEX data
AU/VST3 on Mac, VST3/LV2 on Linux, VST3 on Windows, plus Standalone
It's 100% free, GPL-licensed, and we don't take donations. We just want it to be as accurate as possible, and we'd love help getting there.
Website: https://kayrock.org/kr106/"
