In Part 2 of this DIY project, MrCaliforniaD completes his custom C64 keyboard build, transforming a stripped-down Commodore case and an Arturia MiniBrute keybed into a playable SID-based instrument. Unlike MIDI controllers or modern adapters, this build connects directly to the keyboard matrix of the C64—unlocking access to a wide range of music software without extra hardware.
What makes this C64 keyboard build so unique is its direct compatibility with vintage music programs. Since many SID-based tools were designed for piano overlays that matched C64 keys to musical notes, the keybed mimics those exact mappings. As a result, even obscure titles respond perfectly to the hardware.
Hardware Mapped to the Matrix
MrCaliforniaD explains how the Arturia keybed was rewired so each note closes a circuit within the C64’s keyboard matrix. The keyboard acts like native input—no software or emulation involved. He breaks down the matrix logic, the connector rewiring, and the importance of using the correct contact points to keep the signal clean and responsive.
Analog Controls with a Vintage Twist
Two potentiometers are mounted on the left, cleverly wired through the joystick port to serve as real-time modulation controls. Depending on the software, they adjust pitch bend, filters, or pulse width. This adds a new layer of expression to the already versatile C64 keyboard build.
Clean Mod, No Damage Done
The project uses a VIC-20 case, reshaped with epoxy and filler, then painted and detailed to match the look of a classic C64. Importantly, all mods are reversible. Even the audio reroute through the RF jack avoids damage to the mainboard, keeping the machine’s core intact.
Final Demo and Improv Session
The video ends with performance clips showcasing the keyboard in action. Multiple music programs are featured, including a few that don’t support MIDI cartridges and require direct keyboard input. With the hardware now in place, everything works natively.
This project is a hands-on celebration of SID hardware, presented with humor, humility, and deep respect for the C64’s musical capabilities.
