OPM2151

The ultimate retro FM-synthesis audio chip

Experience the audio that powered such arcade games as Marble Madness, Outrun, After Burner II, and many Williams Pinball machines!

Faithful reproduction

This is not salvaged chip! It is a modern FPGA replacement for a vintage YM2151.

The OPM2151 is a pin-compatible, cycle-accurate drop-in replacement for the vintage Yamaha YM2151 "OPM" 8-channel, 4-operator FM-synthesis chip. Painstakingly reversed engineered from die-shots of the YM2151, OPM2151 is a highly accurate reproduction of the YM2151 and perfectly accurate at the clock edges.

Works with old and new DACs

The original OPM2151 required a digital-to-audio converter (DAC) IC and OPM2151 is no different. OPM2151 integrates seamlessly with existing boards using a YM3012 or YM3014 DAC or with a companion I2S DAC, available as an add-on option here. When paired with an I2S DAC, OPM2151 outputs the full internally-calculated 16-bit digital audio.

The companion I2S DAC fits the same IC socket as YM3012 and the OPM2151 + I2S DAC pair can function as a drop-in replacement for a YM2151 + YM3012 pair. The I2S DAC only works with OPM2151 and requires closing solder jumper "I2S Mode" on the bottom of the board with a blob of solder.

Errata

Some Arcade boards, e.g. the Atari System 1, swap the SH1 and SH2 signals between the YM2151 and YM3012. In order for the OPM2151 + I2S DAC pair to work in an Atari System 1 and similar arcade machines, solder jumper JP1 "SAM Swap" must be closed with a blob of solder.

OPM2151 + I2S DAC pair work in all vintage arcade and pinball systems tested, but they do not work in the Commander X16 due to a bug in the X16 PCB design. A suggested board fix for the Commander X16 will be provided on request.