Luckily, in all the excitement over MIDI, a few thoughtful souls have remembered the vast piles of 'outdated' analogue equipment which any self-respecting synthesist will by now have accumulated. That's the trouble with new 'cure-all' standards – they tend to upset as many people as they please by leaving the silent majority far behind, and the effort of catching up again can be a severe pain in the wallet.

Zypher's Digi-Atom (DIGItal Analogue TO Midi – geddit??!*?) is one of a number of new products designed to solve such problems, and to be crushingly realistic, it's one of the most expensive. It's being imported from Japan by the London Rock Shop, presumably manufactured in relatively small quantities, and so works out at a fair old price. Let's have a look at what you're getting for your money.

The Digi-Atom comes in a 19in rackmounting format, and so is ideal for 'plug it in and forget it' applications. One of its major purposes in life could be to convert signals from, say, a Roland MC4 to MIDI, and the manufacturers helpfully give a diagram for mounting the Digi-Atom immediately beneath such a device. This contains the immortal words "make two side plates of sheet steel about 1.6mm thick" – surely easier said than done. If you are going to use the 4800 in an ongoing-rack-mounting-scenario however, there are two end flanges supplied.

The unit features three DIN sockets which may well not be what you'd expect. One of them is MIDI out, which is fair enough. One of them is a Roland Sync In, for drum machine and sequencer applications. The third is marked 'pass out', which far from having anything to do with the price of the unit, is simply ganged up to the Sync In to relay it elsewhere. Remember there's no MIDI In – this is strictly a one-way converter, analogue to MIDI.

The main part of the 4800's front panel is taken up with jack sockets, of which the first eight are 'CV In' and the next eight 'Gate In'. Inputs from an MC8, MC4, MC202, TB303 Bassline or other sequencer, or from an analogue keyboard, are patched into the CV sockets while the gates are connected up accordingly.

It's then possible to select one of four modes of operation on the 4800; Mode 1 (4-voice poly with independent velocity response); Mode 2 (8-voice poly without velocity); Mode 3 (4-voice and 2-voice poly with group velocity); or Mode 4 (4-voice poly with group velocity, 1 voice without velocity, 1 voice with velocity).

What does all this mean in plain English? Probably nothing, but let's have a go anyway. Composing with an MC4/MC8 will allow you to play back eight-note polyphonic lines on a MIDI keyboard such as the Juno 106, Prophet T8, Yamaha DX7 and so on. The Prophet and Yamaha will respond to programmed information on velocity (so playing louder or more brightly) if you sacrifice four lines of music – the Juno won't do this however many interfaces you use, because it can't respond to velocity information.

Simpler sequencers such as the Bassline will play monophonic sequences on your MIDI polysynth, and if you want some expression you could run another Bassline in sync programmed with velocity information, or you could use an MC202 which stores two lines itself. You can lock sequences up to a Roland clock and some others, but bizarrely enough you can't use a MIDI clock – remember, no MIDI In?

The Digi-Atom has four sockets on the right-hand end of the panel which accept additional information for modulation, bend, release and option. In the case of the DX7 the 'option' is for Portamento on/off (MIDI Input 65), which isn't too exciting; you could use pedals, breath controllers or programmed voltages in conjunction with these inputs to add expression in various ways however.

The Digi-Atom's handbook gives a wide selection of connection diagrams for the MC4, MC202, CMU800, Drumulator, DX9, Modular Systems, TR909 and lots more, and while these wiring diagrams look like a tactical thermonuclear detonation in a spaghetti factory, they seem to make sense. There are lots of helpful tables of connection data and even suggestions as to which sounds could go where – bass notes channel 1, piano channels 2-4, lead channel 5 and so on, and the information on initial calibration seems logical though a little intimidating.

What is worrying is the number of small omissions which seriously limit the applications of the unit. The lack of a MIDI In for clocking has been mentioned, but there's more. The unit only addresses three MIDI channels, 1, 2 and 3, and does this according to what mode you're in, not according to the user's choice. This could make life extremely difficult on some early MIDI synths which can only respond to one MIDI channel. Admittedly the 4800 can produce information covering the entire 10.5 octaves of the MIDI spec, but then instruments like the MC4 go out of tune over this range so not much benefit is gained. There's no flexibility in the clock inputs, so you could be in trouble with Linn Drums, Alpha Syntauris or other exotica.

Sadly it's impossible to review the 4800 without pointing out that Syco Systems have just released their Sycologic Analogue-MIDI interface, which does everything the 4800 does at less than half the cost, and also addresses any MIDI channel, accepts all sorts of Clock Ins, has programmable routing of control inputs and so on. Sorry Ed – there's nothing major the matter with the Digi-Atom, but British technology has beaten the Japanese to it this time.

DIGI-ATOM 4800 MIDI interface: £799