This is a monophonic (single speaker) 2.5 Octave small keys keyboard with 100 tones and split and layering effects. There are also 13 built in songs and a computer aided music function.
This is essentially a monophonic version of the PSS-190 which is exactly the same unit only stereo.
The first 40 voices are the main sorts of instrument sections - Brass,Strings Guitar etc. 40-49 are ensemble voices. 50-79 are dual voices - two layered voices and 80-99 are split voices - two voices spread across the keyboard - there are 19 rhythm styles played on PCM drums and one demo tune.
Voices are selected using the numeric keypad and the green enter key. You can have auto-accompaniment with your rhythms and this is where you can use the computer aided music or harmony function to either ad-lib or create a harmonised melody.
Rhythms and songs are selected by holding down the green Song/Rhythm button and pressing either a black or white keyboard key.
There is a headphones jack and power inlet for 9-12v as well as battery compartment.
This is not really a professional instrument and is perhaps best for a child or learner - but as usual with these instruments there are usually some voices which are useable - but without MIDI these days,such things are either for archivists or for people looking for a pressie for a child that is value for money. These seem to be going for a song on Ebay.
Good points: The overall sounds of Yamaha are impressive and this unit is just as good as some superior instruments. It's a good solid case and eminently portable - so probably useful for carrying to outings and playing around with those ideas you have whilst out in the open without taking your whole keyboard rig with you! It's quite amazing to find split and layering on such a small keyboard and even with small keys it is still playable.
Niggles: There's not a lot to be negative with this unit - you get what you pay for - and you get quite a lot for a small layout - perhaps some of the sounds are not quite good mimics of the real instruments - but they are sufficient for the market that this keyboard was aimed at - perhaps it lacks stereo - but then you can always get a PSS-190 instead.