Yamaha PSS-470

The Yamaha PortaSound PSS-470, a toy keyboard released in 1986 was based on the same Yamaha YM3812 (aka OPL2) FM synthesizer IC used in 1980s IBM PC sound cards. It has 9 voice polyphony or 6 voices with 5 drum sounds.

Editable sounds
The PSS-470 is more versatile than most toy keyboards in that allows custom percussion rythms and has simple manual editing using six sliders for shaping the FM sounds.
 * Wave selects the sound colour.
 * Spectrum adjusts the pitch of the sound selected by the Wave setting. Reducing this will enable deeper bass sounds.
 * Modulation adjusts the sound brightness.
 * Attack adjusts the time a note takes to reach its peak volume.
 * Decay adjusts the time a note takes to become inaudible.
 * Volume controls the output level of the synthesizer section.