"-hard plAYer- is an 8 bit tunes hardware player, which allows you to listen to the same melodies you could listen to in some of the 80's home computers and videogame consoles. In next versions It will also work as MIDI synthesizer. It's audio sound generator porcessor is the General Instruments AY-3891X the same one that was used in vintage computers like the Atari ST, Amstrad CPC, Spectrum ZX, MSX, Oric, or Colour Genie, and consoles like the Intellivision or Vectrex. The YM-2149 was a Yamaha's licensed version of this processor."
more info including more video here
hard plAYer's hardware overview
YouTube via Tolaemon
"This video shows hard plAYer's hardware : the microcontroller, the SD card slot, the power supply, MIDI adaptor, AY-38912 PSG, the LCD and the simple mixer."