Sometime last year, among the hoo-ha surrounding FM sound, the DXs and PFs, Yamaha quietly brought out a range of preset FM instruments called the Clavinovas. At the time it was not exactly crystal clear which market these impressive if quirky instruments were aimed at; Yamaha had already made a major impact on the electronic piano market with the PF10 and PF15, public attention was focussed on them, and the few extra features on the Clavinovas were marketed so vaguely that most people remained happily unaware of their existence. They offered similar sounds to the PFs plus a few additional ones, big wooden weighted keyboards, touch sensitivity and nicely-styled cases to match the furniture, but had no real image and no proper sales drive. More recently they have been finding their way into a few shop windows, but it was clear that the instrument needed something extra in order to set it apart from its competition.

Yamaha have never been prone to doing things by halves, so the newly-launched range of Clavinova models have so much extra on them for less money that it's hard to believe it's the same concept. The new Clavinovas are categorically stated to be digital pianos, aimed at the pianist who wants more from an instrument or, with its wealth of automatic features and computer memories, the novice who wants to be able to play instantly and wants more than a basic portable keyboard without the second mortgage needed for the big organ-like multi-keyboards. So where does that leave the budding Rock star?

Well, to start with the rhythm unit built in to all models is not the tickety-bonk-tish variety you might expect but a proper digital drum machine with nicely-recorded PCM sounds, unfortunately not programmable but offering 16 tastefully programmed patterns, each with a fill bar which can be added manually or automatically every four or eight bars. Each pattern also has two handclap options providing a surprising amount of variety to the basic feel. The usual automatic accompaniment features you expect from portables are provided, with the machine playing bass and chords derived from your left-hand chords in a style to suit the rhythm pattern in use. Two variations are offered for each pattern, and while the sounds used by the accompaniment are preset they are carefully chosen to suit the rhythm style, and reveal the multi-timbral capabilities of the instrument; the automatics could be playing, say, bass and guitar, while you remain free to use any of the 16 preset voices with the right hand. It's possible to double the right-hand line up the octave to fatten things out a little, and if the accompaniment is getting a bit heavy-duty for a piece you can select 'staccato' which thins it out a little.

The sounds themselves are particularly strong, as you'd expect from a Yamaha FM instrument. The emphasis is on pianos and keyboard instruments, with two acoustic pianos, one bright and one mellow, two electrics, clearly intended to be a Rhodes and a Wurlitzer, two harpsichords, one light and classical and one harder and rockier, and a celeste. Vibes and marimba are familiar from the PFs, but sound to me as if they've been improved slightly; there's even more bite and more feeling of stick hitting bar. The acoustic guitar is not going to fool anybody into believing you're John Williams, but is streets better than the usual diaster you get on keyboard instruments trying to be guitars, while the other guitar is a pure DX sound. The remaining five buttons are cryptically labelled 'Clavinova Tone 1-5', apparently to avoid detracting from the piano image, but provide good realistic imitations of brass, pipe organ, Hammondish organ and flutes (complete with a nice little chiffon the front) plus one big fat noise that couldn't be anything other than a Yamaha sound.

Next up come the various memory facilities. The simplest is a step-time chord or bass sequencer, where progressions can be entered a note at a time; these can then be handed over to the automatic accompaniment to provide a full programmed backing to a song. Much more sophisticated is the performance memory. This provides two independent synchronised data tracks which record performance data in real time, using the drum machine as a guide track. The tracks are rather misleadingly labelled Left and Right; in fact both tracks use the whole keyboard. A further option is to split the keyboard (there are three programmable split positions) and record bass in the left hand and chords, using any of the preset sounds, in the right. On playback you can play along using the whole keyboard with any of the presets, thus making three separate sounds available simultaneously.

But the most elaborate memory system is, would you believe, plug-in music. You've all seen those playcard things where you run the edge of a piece of music through a slot and the instrument reads data off a bar code, loading the music into memory; well the ROM music book goes one (or even possibly two) better. You get a whole book full of music, and all the data the Clavinova needs to play every piece in the book is stored on a ROM chip attached to the bottom of the book. When the book is sitting in the instrument's music rest the ROM plugs into the socket and all the data is available at the touch of a button or two. The music is divided into three parts (left, right and orchestra) and any part can be turned down or off to allow you to play along in its place. The tempo is adjustable, but if you still get left behind you can switch in the guide system, where LEDs above the keys tell you what note you're supposed to be playing next, and the rest of the instrument actually waits for you to play it. This can, as you would imagine, make the music more than a little fragmented, but may be useful for practice. It's even possible to practise a piece in sections; you can call up a particular phrase and the Clavinova will repeat it until you've mastered it.

If you think this all sounds like a Semprini course for wallies, you're not far wrong, although the variety of music due to be made available looks impressive; but before long you will be able to buy RAM packs attached to manuscript paper so you can programme your own music in the same way. The emphasis in the Yamaha literature is on the educational aspects — get your teacher to play scales then try to keep up — but it could just as easily be seen as a powerful songwriting tool and demo preparation system. It should be a piece of cake to throw a song together on the various bits and pieces the Clavinova has to offer to play to the rest of the band at the next rehearsal, just as people have been doing on the Casio and Yamaha portables. But with the Clavinova you've also got the bonus of a quality musical instrument, easily on a par with the PF15 with several extra sounds, plus Yamaha's usual stereo chorus and MIDI. Other features include soft and sustain pedals — unusually the sustain pedal has a variable effect depending on how hard you press it — plus a chunky wooden stand supplied as standard, built-in speakers and stereo line outputs.

Keyboards loaded with ee-zee-play features tend, often with considerable justification, to be seen as little more than toys; the Clavinova certainly doesn't fall into that category. For one thing they're much too expensive to be playthings, and besides they exude quality. The keyboard alone has such a good feel to it that it would make a good master keyboard for a MIDI system, and if the PF pianos are anything to go by the Clavinova is worth their price for the sounds alone, never mind all the hi-tech jiggery-pokery on board. If you're in the market for a good electronic piano, make sure and try one; they may not have been designed with you in mind but they've got an awful lot to offer.

YAMAHA CLAVINOVA CVP-5 - RRP: £1599