Toshiba HX-MU900
This page was last modified 23:32, 17 March 2018 by Rderooy. Based on work by Mars2000you and Gdx and others.



The Toshiba HX-MU900 is a crippled MSX-AUDIO extension. It lacks built-in sampleRAM, MSX-AUDIO ROM and a sound input to be complete. Instead a software called Synthe Music Editor is built-in.

The product name is "FM-synthesizer unit". It was made in Japan, but only sold in Europe.

Brand Toshiba
Type HX-MU900
Year 1985
Region Europe
Official price NL: ƒ399 (incl. HX-MU901)
Package content


Toshiba HX-MU900
Toshiba HX-MU900
Toshiba HX-MU900 back
Toshiba HX-MU900 with 32kB
Toshiba HX-MU900 upgraded with 32kB back


Input CALL SYNTHE under Basic to run the built in software.

The HX-MU900 can be upgraded to an MSX-AUDIO. (See links below)


  • Connector for a standard MSX-AUDIO Music Keyboard (usually the Toshiba HX-MU901)
  • 2 RCA mono Audio-out connectors


Whatever the upgrade, the microphone jack will be missing.