Not the latest of Roland releases, but still the flagship of the series, the Jupiter 8 was introduced to a hungry world about 18 months ago. I say hungry because there had been rumours and tasters about the project for a year and a half before it finally appeared in a perfected state.

At the time it broke all the rules — 64 memories instead of the standard 32 or 40, a split keyboard for different sounds on your left and right hand, an overlay facility to give you two sounds at once from one note and an arpeggiator, until then a feature spurned by expensive polysynths as being too "Woolworth's".

By now other manufacturers have caught up. Prophets and Oberheims have 120 memories, the OBXa can also split and double up settings and the soon-to-be-released Memory Moog will have a comprehensive arpeggiator.

Which all suggests that the JP8 may soon be subjected to an overhaul and update by Roland. Never a firm to rest on their laurels, they are almost certainly working on a JP mk2, but until then, this Jupiter remains a formidable opponent in the polysynth field.

Physically the case is long, remarkably slim, mildly heavy and finished in two slinky brushed aluminium end cheeks. At its tallest it's just under 4¾in. and scales in at 21.5kg. The 61 note five octave C-to-C keyboard is firmer and quieter than older Roland types and the synth can handle up to eight notes at once or four when the sounds are overlayed.

Most of the controls are on sliders, the exceptions being those for waveforms and footages, tuning and volume. On the back lurks the usual jack outputs for cassette loading, CV and gate, VCF, VCA, portamento and hold foot switches, a clock from the arpeggio section and Cannon outputs for the upper and lower halves of the keyboard.

To help on-stage changes, the JP8 has eight patch preset buttons which will instantly call up eight pairs of sounds. The keyboard splits 24 notes up from the bottom and this division cannot be programmed to fall anywhere else, something the OBXa can do. Otherwise memory selection is through a further eight buttons — the first pressed selects the bank and the second one you hit chooses the position within it.

The requested program appears as figures on a large LED readout covered by clear Perspex at the centre of the front panel. In fact there are two sets of figures, one for the lower half of the keyboard, the other for the top and two decimal points light in the display to show you've edited a sound.

Like most latter-day polys, the controls are in permanent edit, so as soon as you move them the sound is changed, but the original stays locked in the memory.

There's a total of 16 oscillators in two banks and when switched on the synth goes through an automatic tuning sequence — twice slowly, twice quickly — to bring them all into line. It takes five to six seconds and subsequent check tunes are done in two.

Past Rolands have had a reputation for flimsiness of tone. These new oscillators are an improvement. Roland have fattened them up and strengthened the filter to 24dB as well as adding cross modulation where one bank can "interfere" with the other.

Yet the clean, predominantly piano-like qualities of Roland synthesis are maintained.

The Jupiter has a crisp, cutting edge that some keyboard players find "plinky", but which ideally suits the hard, insistent jangle of techno-pop.

In scouting around rival synths, Roland have produced a machine which pulls together many of the most popular features found on the shelves. For example it can mimic settings that made the Prophet famous — the downhill clangs and bellicose organs — but for silky, warm, background strings the Polymod section of the Prophet 5 gives it a head start.

The modular section is excellent in detail — you can route polyphonic portamento, modulation or bend to either half of the keyboard, osc bank 1, osc bank 2, etc — but it's disappointing in practice. Vibrato is brought in not by a wheel but by a white button. It's all or nothing, you can't fade the modulation in, which seems surprising considering the wealth of facilities elsewhere.

The arpeggiator will scan through all the notes you're holding down, picking out one at a time either up the scale, down, in both directions or completely at random. It can reproduce that scale within an octave or up to four. The JP8 has a hold facility to sustain chords indefinitely when your fingers are off the keys. One of the few tricks it can't manage is to store a chord shape then reproduce it in a new key when you hit another single note.

The cassette load of memories can be checked — an "error" sign flashes in the readout if the information has been scrambled. The memory backup battery is supposed to be lifelong since each time you turn the JP8 on at the mains, it recharges the cell for you.

When originally released the JP8 had only one serious weakness. After spending nearly four grand on your new purchase, you couldn't hook it up to a polyphonic sequencer or one of Roland's own Microcomposers. That's now been sorted and for a few hundred pounds an extra "magic box" can be fitted to allow access to the individual CV and gates for the oscillators.

It would be smart if further developments enabled the Microcomposer to change memories on the JP8 as well as notes, for at the moment you have to lean over the synth hitting the appropriate buttons at the right time.

£3,900