Bitcrust / Manual

Introduction.

Bitcrust is a SID-inspired polyphonic synthesizer with an in-house MOS 6581 / 8580 DSP core. Twelve voices. Three oscillators per voice. Written from scratch against the original datasheets, then quietly extended with features the chip was never built for.

IS

What Bitcrust is

A modern synth with SID architecture — not a bit-accurate emulation.

12-voice polyphony. 3 oscillators per voice. Dual chip-model character (6581 / 8580). Multi-mode TPT filter. 8-slot mod matrix, 6-slot FX rack, tempo-synced arp, 16-step sequencer.

115 factory presets, A/B compare, dirty-state marker, Hold (note latch), 14 bundled themes, live visualisations, comprehensive MIDI learn.

On-screen keyboard cycles through Piano, BigPiano, Launchpad-style Grid, and FullGrid modes — touch-first on iPad, mouse-friendly on desktop.

Integrated MIDI file player in the Standalone build (Bach Well-Tempered Clavier prelude/fugue pairs bundled). Headless CLI for offline render and preset validation in the same binary.

IS NOT

What Bitcrust isn't

Not a cycle-accurate emulator.

Not a sample-playback engine.

The DSP is written from scratch in C++ against public datasheets. The 6581 / 8580 architecture is the starting point, not the destination, and the engine extends it with 64-bit internal processing, smooth filter crossfading between chip revisions, and per-oscillator volume control.

01

Install.

Pick your platform. Apple users go through the App Store; Windows and Linux users download from the Gumroad store.

macOS

  • AU
  • VST3
  • Standalone

Apple Silicon and Intel. One purchase covers macOS and iPadOS (Apple Universal Purchase).

App Store →

iPadOS

  • AUv3
  • Standalone

On-device Audio/MIDI settings. Included with the macOS purchase via Apple Universal Purchase.

App Store →

Windows

  • VST3
  • Standalone

Installer places the VST3 bundle and Standalone executable in their standard locations automatically.

Gumroad store →

Linux

  • VST3
  • LV2
  • Standalone

tar.gz archive. Drop the VST3 bundle under ~/.vst3/ (or your DAW's scan path); Standalone binary anywhere on $PATH.

Gumroad store →