When Casio first began making keyboards I was disappointed to find them only slightly above 'Stylophone' class. I couldn't understand why a company who seemed to be at the forefront of chip technology should want to waste their time on toys... but I'm not a businessman, am I!

Quite apart from creating an entire genre of instruments over the last four years or so, Casio have gradually become more sophisticated with the passage of time. It's almost as though they had a specific age group in mind when their first keyboards were launched, and as this age group has grown up and developed, so have Casio.

I must say, though, that I'm getting a bit weary of this whole 'Casio go Pro' number. Okay, so the CZ-101 is a programmable polyphonic synth, but what is - or isn't - a 'pro' instrument?

The CZ-101, for example, allows the user to program his/her own sounds - good sounds - but it's equally important to realise that it has a relatively mini keyboard, and only 16 user-programmable locations at present. 16 further sounds are offered which can be edited although not stored, but there will be a cartridge option sometime soon.

The CZ-101 is an eight-note (maximum) polyphonic, and its digital sounds are edited and programmed by an interesting method which lies somewhere between regular synth programming and FM programming. Casio's concept of 'phase distortion' is easier to grasp than FM though, and has been presented in a way that allows you to achieve adequate results quickly and then spend more time learning how to create and cope with more complex patches when you feel ready.

The sound is created in two banks - both totally independent - which allows layering or combination patches to be written. It's broken down into three distinct areas under the headings 'DCO', 'DCW' (wave, performing filtering or timbral tasks like a VCF) and 'DCA'. Each of these three sound components has an eight-stage envelope generator applied to it, controlling its sound through time. Mercifully, you don't have to use up all eight stages of contouring, so programming isn't necessarily a year-long affair. The system uses a form of digital access control. DCO 1 and 2, DCW 1 and 2, and DCA 1 and 2, each have their own initialising button. Each also has an 'Env' button alongside.

To program a sound from the beginning, you select, for instance, DCO1 and choose a basic waveform. These can be seen underneath the small LCD screen, beneath which are two value and two cursor controls. Your choice of waveform can be from sawtooth, square, pulse, double sine and saw-pulse, any two of which can be combined. In addition to these are three extras - Resonance I (sawtooth). Resonance II (triangle) and Resonance III (trapezoid). Some of these are only slender variations on a theme - especially by the time you've finished applying umpteen envelope stages to them - but the basic sounds are quite strong, and very clean. You may miss a certain warmth provided by analog or digital/analog synths, though. Once you've settled on a waveshape you can use the DCO Env button to make changes, and so with the other two basic parameters.

Casio have provided some useful short cuts for those unwilling or unable to step through every possible permutation. When using the envelope generators (which offer five stages of key-on attack, a sustain point, and three stages of key-off release) you move on from stage to stage using the 'env step' buttons (then editing accordingly) or you can use the 'sustain' or 'end' buttons to get to these stages earlier. At each stage you have control over 'rate' and 'level', determining the way in which your sounds go through these stages. Also there's a compare/recall device, so you can keep a check on how your programming is or isn't making headway from where you started. Vibrato (named as such) can be programmed into your sound using any one of four waveshapes, and can be ditched or activated thanks to a vibrato on/off push button on the performance panel. It's a bit sudden, presented like this, but it can be handy to just bring in a spot of vib. at the top of a pitch bend or what have you. Just using one set of DCO controls gives you eight-note polyphony. It sounds a little thin, to be honest, and most times you'll probably want to use the double sound generation (DCO1 plus DCO2 etc.) and thereby have four-note polyphony. You can quickly reassign your oscillator configuration thanks to the 'Line Select" button, which will activate DCO1; 2; 1 plus 2; or 1 plus 1. Beneath this control with its four LEDs are controls for ring modulation and noise, both preset. Ring modulation creates extra high harmonics when a combination of oscillators is used, and results in a more bell-like, 'clangorous' version of mucho resonance on a regular synth's VCF panel. Noise is white, and noisy!

Performance-wise, there's a pitch wheel - in a slightly uncomfortable position if you're playing the CZ-101 standing up - with a bend range control. Portamento is on hand, with on/off and time controls. This is a MIDI keyboard, and you'll probably take advantage of that fact to channel the CZ-101's sounds through another keyboard. This relieves your fingers of the tricky matter of negotiating the Casio's small keys, which, if the instrument is to be judged solely on its own merits, might put some people off. The sounds, on the other hand, are very impressive - especially when two are combined. Casio make it easy for you to use the CZ-101 as a stage-portable keyboard, with strap buttons on either end. Since tones can be mixed (even two double generation ones, which then makes this a monophonic instrument), the resultant lead line sounds can be frightening - and wandering around stage playing some of the tone-mixed sounds is highly recommended!

For the money (RRP £395), the CZ-101 is undoubtedly a Class A bargain, and it's bound to be a big seller. A version with full-size keyboard will be launched later in the year, along with further Casio 'performance' type keyboards. If they're to this standard, then they're sure to do well, too!

RRP £395 inc. VAT