The devices from the Yamaha PSR series already belong to the more professional arranger instruments with large-sized standard keyboards. The PSR-90, released in 1987, is a leading-edge product of the line, with functions extended to the max.
The high-quality FM sounds are split into solo and poly sections and can each be processed through 4 step synthesizer functions. On top, you get a row of vibrato, chorus and sustain effects. The beat section sounds downright dynamic and is highly reminiscent of the drum machines from the RX series. Next to the 20 presets, 3 patterns can be freely programmed and saved on longterm basis. Programming is very comfortable and easy with very good bass and chord sounds, which can be freely chosen.
The great range of functions and separate volume controls for the components make the devices from this series enormously versatile. Up to now, I've only built mute switches for drums, chords and bass into mine.