RE2-YM2608 - Project RE:birth 2nd Sound Card

What is it?

Project RE-birth 2nd is the spiritual continuation of Project RE-birth — a legendary open hardware project dedicated to bringing classic FM sound chips back to life.

In 2021, for unknown reasons, the Japanese closed the ym2203.com website, deleted all public schematics, and stopped the distribution of all peripheral hardware. Even with money in hand, it became impossible to purchase any SPFM motherboard or rebirth module. This was deeply frustrating for enthusiasts worldwide.

In the absence of original hardware, I forked almost all RE-birth music modules to truly revive this project. My mission: make FM music chips available to people all over the world — no internal meetings, no mystery stores, no hunger marketing, just long-term stock and fair play for everyone.

The RE2-YM2608 is a YM2608 (OPNA) sound card designed for the SPFM series. The circuit is fully redesigned by myself and is compatible with the RE:birth bus. It can be used with SPFM Light, SPFM Lite, RESPFM, IAP-RESPFM, STM32-RESPFM and other compatible motherboards.

About the YM2608 Chip

The YM2608, also known as OPNA (FM Operator Type-N Advanced), is Yamaha's most powerful PC sound chip of its era. It combines 6 channels of 4-operator FM synthesis, a 3-channel SSG (PSG) section, a rhythm sound generator with built-in samples, and a full ADPCM channel for high-quality sample playback — all in a single chip.

The YM2608 was the heart of the legendary NEC PC-98 computer's sound system, powering some of the most iconic Japanese PC game soundtracks ever composed. From the sweeping FM orchestrations of Falcom's Ys series to the driving rhythms of countless doujin games, the OPNA sound is deeply embedded in retro gaming culture.

With the RE2-YM2608, you can experience that full, rich OPNA sound — FM, PSG, rhythm, and ADPCM — driven by the authentic hardware chip.

Key Features

• Authentic YM2608 (OPNA) — 6-ch FM + 3-ch SSG + rhythm + ADPCM on one chip
• ADPCM sample playback support (correctly loadable on STM32-RESPFM)
• Compatible with RE:birth bus standard
• Works with SPFM Light, SPFM Lite, RESPFM, IAP-RESPFM, STM32-RESPFM and more
• Classic NE5532 dual op-amp for excellent audio output quality
• Adjustable volume control on-board
• Excellent digital-to-analog isolation for clean, noise-free sound
• Standardized RE:birth module form factor
• Long-term stock — always available, no artificial scarcity

Supported Chips

• OPNA: YM2608

Compatible Mainboards

• SPFM Light
• SPFM Lite (2 slots)
• RESPFM
• IAP-RESPFM (4 slots)
• STM32-RESPFM (4 slots) — full ADPCM support

Why Did I Make It?

I referred to original rebirth module schematics and pictures, as well as the SPFM Tower schematic, to faithfully recreate this module. My dream is simple: to make SPFM and RE:birth modules available to everyone in the world — no gatekeeping, no mystery shops, fair play to all.

Thanks to the extensive experience accumulated in designing MegaMod and other RE:birth modules, this module was designed and validated within a week.

What Makes It Special?

The RE2-YM2608 features a clean, minimal appearance with the YM2608 chip logo and key parameters printed on the board. It uses the classic NE5532 universal dual operational amplifier, delivering adjustable volume, excellent sound quality, and solid digital-analog isolation — fully in the spirit of Project RE:birth.

As the most feature-rich chip in the RE:birth 2nd lineup, the YM2608 offers unmatched versatility: compose with FM, layer in PSG arpeggios, trigger built-in rhythm samples, and play back ADPCM audio — all from a single module slot. It is the ultimate choice for PC-98 music enthusiasts and OPNA composers.

The RE:birth module design philosophy pursues the ultimate in sound quality, standardized appearance, and thoughtful bus layout with proper ground plane isolation — just like a textbook.