YM7129 FM Operator Type-K2 Sound Card

What is it?

YM7129 FM Operator Type-K2 is a modern sound card built around Yamaha's rare YM7129 integrated FM synthesizer. It faithfully recreates the architecture of the YM7116 with identical 2-operator FM synthesis across 8 stereo channels, delivering the quintessential 1980s Yamaha FM tone. The chip also integrates a 4-channel ADPCM rompler and 6 monaural rhythm sounds, making it the complete sound engine found in iconic PortaSound keyboards: PSS-280, PSS-290, PSS-380, PSS-390, and PSS-26. This card brings that nostalgic FM keyboard experience to modular and DIY audio setups.

Why did you make it?

The YM7129 represents a sweet spot in Yamaha's FM evolution—more capable than early OPL chips yet overlooked by modern projects that focus on OPL2/OPL3. These chips are salvaged from aging PortaSound keyboards that increasingly end up in landfills. By extracting and preserving the YM7129 on a dedicated card, I wanted to rescue this unique FM+PCM hybrid voice architecture for synthesizer enthusiasts, chiptune artists, and vintage computing hobbyists who appreciate the distinct "budget FM" character of late-80s consumer Yamaha gear.

What makes it special?

• Authentic YM7129 core: 8ch stereo 2-op FM identical to YM7116, no emulation or approximation—pure vintage silicon character.
• Integrated ADPCM rompler: 4 independent PCM channels plus 6 dedicated percussion voices (bass drum, snare, hi-hat, tom, cymbal, clap) in monaural mix.
• PortaSound heritage: Verified compatible with voice maps from PSS-280/290/380/390/26 keyboards—patch compatibility for vintage tones.
• Hardware-complete design: All analog output stages, filtering, and level matching implemented; ready for audio connection.
• Critical note—software driver experimental: Register-level documentation exists, but ready-to-use drivers (MIDI, tracker, or sequencer integration) remain incomplete. Buyers receive hardware schematics, YM7129 datasheet excerpts, and community starting points, but must develop or adapt their own control software. Recommended for developers, reverse-engineers, and adventurous builders comfortable with bare-metal FM chip programming.