Ploopy offers open-source hardware headphones with an amplifier based on a Raspberry Pi RP2040, a Texas Instruments PCM3060 24-bit DAC, and an amplifier circuit, as well as 3D printed parts and open-source firmware written in C.
The project is reasonably well documented, and you can build it from scratch.
The electronics are comprised of two boards:
- The Gould amplifier board with the Raspberry Pi RP2040, Texas Instruments PCM3060 24-bit 96/192 kHz DAC, and several TI OPA1688 audio operational amplifiers
- The Mazzoleni driver flex boards going into the left and right rings with a TRRM jack each.
Both boards are designed with Altium Designer.
The project comes with plenty of 3D printed bits available in DXF, STL, and STEP formats, and shown below as part of a complete kit with the electronics, cables, and fixtures.
Finally, you’ll also get the ploopy_headphones.uf2 firmware and its source code. Everything can be found on GitHub with the firmware released under GPLv3, and the hardware is under an OHL CERN v2-S license. You’ll find detailed assembly instructions in the Wiki section of the project’s GitHub repository. All in all, the Ploopy open-source hardware headphones project is impressive both in terms of its openness and documentation. I just wish I hadn’t had to open the schematics to derive some of the specifications for the amplifier board ;).