94.7 MB

A synthesizer plugin emulating the Roland Juno-6, Juno-60, and Juno-106, built with JUCE.

6-voice polyphonic with dual-mode DSP (Juno-60 analog / Juno-106 firmware), per-voice analog variance, TPT ladder filter with OTA saturation, ngspice-verified BBD chorus, arpeggiator with DAW sync, portamento, and 240 factory presets (112 Juno-60 + 128 Juno-106). Parameter curves calibrated from hardware measurements, circuit simulation, and firmware analysis.

Formats: AU, VST3, LV2, CLAP, Standalone Platforms: macOS (10.15+), Windows, Linux

SysEx: Full Juno-106 SysEx support (IPR/APR send and receive). A separate AU variant (aumf) is included for Logic Pro, which blocks SysEx on standard AU instruments.

Full documentation

Ultramaster Group was born in the year 2000, in a loft in Brooklyn, NY. Our bold mission: professional-grade audio software for the Linux ecosystem. We were young, idealistic, and perhaps a little bit ahead of our time.

Life eventually pulled us into different orbits. Karl went on to found the art and design powerhouse Kayrock Screenprinting, while Dave joined the engineering teams at Google. But the music never truly stopped.

Twenty-five years ago, we were targeting the Pentium Pro, working without the luxury of oscilloscopes, service manuals, or community hubs like ModWiggler and Reddit. Today, after decades spent designing Kayrock Powertools and scaling global infrastructure, we’ve returned to the Juno source code.

A lot has changed since the late 90s. Hardware is exponentially faster and DSP methodology has evolved. We have spent time heavily recalibrating and refining the engine for the modern era. While the interface remains intentionally familiar, the internal architecture has been overhauled for better performance and precision.

We are rereleasing KR-106 as an open-source project under the GPL to give back to the community that inspired us from the start. Our goal is to make this as accurate as humanly possible, and we would love for you to help us get there.

Visit Developer Site

KR-106.2.5.12  ( 95 MB )