I recently became interested in how FM synthesis for music generation works. To facilitate that I designed a FM synthesis sound card for the RC2014.
The design is available here: https://github.com/electrified/rc2014-ym2151
It’s still a work in progress - I’m a beginner when it comes to operational amplifiers and analogue electronics, and the DAC chip that accompanies the YM2151, the YM3012 requires a pair of op amps for it’s output stage.
Currently I’m using a pair of NJM4556A opamps, which are appropriately “vintage” but may not be the best choice. I also may not be biasing the opamps correctly! I am hoping to experiment with generating higher (and negative) voltage rails for use with the opamps.
This is my first design using KiCAD 6 from scratch, and I’m really liking it. I’m also using Github Actions and Kibot to generate the Gerbers. This removes the possibility of the checked in design not matching the Gerbers, and ensures all the DRC and ERC checks are run, applies the version number, before generating the output artifacts (gerbers and PDFs).
In terms of music playback, the largest library of YM2151 music is for the Japanese Sharp X68000 computer, in the form of MDX files. I have begun a port of an Arduino MDX player to CP/M / RC2014 here https://github.com/electrified/mdxplay-rc2014
The other source of existing music is arcade boards, there are a quite a number of VGM rips featuring YM2151 sound.
A post announcing the new design is here https://groups.google.com/g/rc2014-z80/c/fi9vizSVriI