Review - Sound on Sound magazine, September 1994

For better or worse, vapourware is a fact of life in the musical instrument industry: notable recent examples include the Waldorf Wave and Oberheim OBMx, both of which have taken years concept to production. You could add to the list Kenton's rack-mounting Pro 4 multi-channel MIDI-CV interface. This product has been In development since the company's original Pro 2 two-channel MIDI-CV interface was launched.

But to be fair to Kenton they have spent a lot of time making sure that what is actually implemented on the Pro 4 is what musicians want. Originally, the new interface was simply going to be two Pro-2's in a box - an attractive concept in itself. However, the company kept tabs on their feedback from Pro 2 customers and found that it wasn't too much trouble to implement some of the more popular suggestions. This attention to detail and customer requirements has resulted in the delay in releasing this unit - and let's say right away that it certainly has been worth the wait.

Panel games

The front panel of the Pro 4 isn't as cryptic as the Pro 2's. Editing is undertaken through the use of four buttons a data entry knob and a two-line by 20-character backlit LCD. The Pro 2, with its row of LEDs and two-digit LED display, was never that difficult to programme, but the Pro 4's LCD makes light work of customising the new machine. Activity LEDs are provided for the four main MIDI-CV channels (labelled A,B,C and D) MIDI data input and MIDI clock As with the Pro 2 each MIDI-CV channel is provided with mini pots, accessible through holes in the front panel, for adjusting the tuning and octave scaling of the Pro 4 to your synths.

Inside story

The most important point to understand when operating the Pro 4 is that, although it is nominally a 4-channel interface, it actually offers far more than this: it's divided into eight independent sections, labelled A to H, each individually addressable on separate MIDI channels. The Pro 4 also provides a Sync 24 output, a programmable sync socket, eight auxiliary cv outputs and four programmable LFOs.....


The Pro 4 is one of those rare devices where the back panel is as interesting as the front. Nearly all connections are on mini-jacks (20 in all); there are also MIDI in,Out and Thru sockets, the Sync 24 DIN socket, and a pair of 15-pin D-type sockets that provide the outputs for the Wasp/DCB and KADI channels. The only other connector is a three-pin mains socket for the internal PSU. To be honest, mini-jacks are a bit of a pain, but I can see that using quarter-inch jack sockets would have added to the unit's cost, as well as making it more untidy and crowded at the rear. However, once it's plumbed in, the fiddliness of mini-jacks ceases to be an issue - some users may like to wire up a dedicated patchbay.....


I found the Pro 4 a doddle to use - the data knob and clear LCD make for straightforward programming. The calibration pots were a bit fiddly for me, but the Pro 4 probably isn't going to be recalibrated everyday. If you use a Wasp and a DCB-equipped synth, you'll need to shell out for a splitter lead (both channels share a socket due to space considerations), and Hz/V-equipped synth users will need the optional board, but that's a bout the limit of my operational complaints. I don't have a Wasp or a DCB-equipped synth, so I couldn't test out every corner of the Pro 4. I could, however, have it chucking out notes on two channels along with Sync 24 and an arpeggiator clock; it didn't fall over, and added no discernible delays. Even though the machine we reviewed was a beta test model I had no problems. Pre-production models often have incomplete software or bugs and the like, but not the Pro 4.

It's hard to fault the Pro 4: the flexibility and stability of the final product is testament to the thought that has gone into development. Pre-MIDI synths are still enormously popular, which virtually assures the market for the Pro 4. Had it simply been a four-channel MIDI to CV/Gate convertor, it would have offered good, if not stunning value. In actuality, it is a really excellent buy: Kenton have gone overboard on facilities, some of which simply aren't available elsewhere. The Pro 4 can control up to eight synths directly, on separate MIDI channels, as well as synchronising a further two drum machines or sequencers to MIDI. Beat that for under 450 - it works out at less than 45 an instrument. A wide range of triggering options, auxiliary CVs and four LFOs make Kenton's Pro 4 a virtually unmissable piece of hardware -only certain MIDI internal retrofits would come anywhere near the facilities on offer here, and that couId be rather an expensive aIternative. If you have more than a couple of vintage synths or drum machines, and want to interface with the MIDI 9Os, then you can't afford to be without a Pro 4.

Review by Derek Johnson

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