Toshiba HX-MU900
This page was last modified 10:28, 1 November 2016 by Rderooy. Based on work by Gdx and Retrofan.



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

Product name is "FM-synthesizer unit". It has made in Japan, but only sold in Europe.


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.