Just before the British Trade Fair last August I received a circular from Hohner stating that they would be announcing a surprise new instrument at the Fair. I was well acquainted with their two other 'best sellers' — the Pianet and the Clavinet - so when I found out that the surprise instrument was an amalgamation of these two stablemates I was very keen to get my hands on one to review for your (and my) favourite magazine. After having literally taken the instrument apart, it seemed to me that it wouldn't be a bad idea to examine all three instruments together in one review. So...

The Pianet has been in production for as long as I can remember. More keyboard players seem to have started their electric music careers with the Pianet than with any other keyboard instrument. The Pianet T has evolved from the earlier model N, which was mains powered, providing a tremolo facility and more often than not a permanent mains hum facility. The Pianet T got round most of the ATs problems by disposing of the mains supply and just feeding the signals from each note directly to the output via a transformer. It is an electro-mechanical instrument, but it doesn't even need a battery. Just plug into an amplifier and play away, just like a guitar.

The Pianet T comes in a smart slimline black case with hinged lid, underneath which is a 60 note F-E keyboard; nothing else, no tone controls, nothing. On the back of the instrument is the output jack socket. The instrument produces its sound in a very clever and simple way. Each of the 60 keys has a corresponding vibrating reed, which is plucked by plastic suction pads. The resulting vibrations are then, converted into electrical energy via the electro-magnetic pickup. The reeds immediately become damped on release of the keys. Each reed is of a different length to give different pitches, and fine tuning is obtained by adding to, or removing from, a small blob of solder on the end of each reed.

The Pianet T is a one sound instrument, nevertheless the sound produced is very pleasing. It is clear and well balanced over the range of the entire keyboard (a statement not often applicable to some far more expensive instruments). The Pianet does provide quite a fair amount of touch sensitivity, though not nearly as much as one would find on an acoustic piano. There is a reasonably long decay to held notes, so that long, slow chords can sound full, though when the key is released the note is killed dead. The keyboard itself has a light action and therefore most people will find the Pianet T fast and easy to play. The Pianet, although somewhat limited, is quite remarkable and, despite its one sound, clever use of effects pedals can result in some amazing sounds.

The beauty of this instrument lies not only with its smart slim-line case, portability, warm sound and very reasonable price, but in the simplicity of the design (there is next to nothing that can go wrong). So, all things considered, it looks as though Pianets are going to be with us for quite a lot longer.

The Clavinet D6 first appeared around 1970 and has become a unique keyboard instrument, the most sincere form of flattery coming in the form of imitation — most polyphonic synthesisers now have a 'clavinet' preset or patch. The Clavinet, as it is so distinctive, is seldom used as a keyboard player's sole instrument. But the instrument's popularity leads to its presence somewhere among most large keyboard set-ups. As it is a very percussive and cutting instrument, the Clavinet seems to have become most at home in 'funky situations' (who said that?).

Again this instrument is electromechanical, though it does use a 9-volt PP3 battery to power an active tone circuit. It has a 60 note F-E keyboard that is touch sensitive. Well, how does the Clavinet get its distinctive sound? The answer goes something like this: When a key is struck a plunger underneath touches the string and presses it on to an anvil. The string impinges on the anvil with a strength depending on the key pressure, thus affecting the dynamics of the sounding string. To make this clearer, compare it with the hitting of a string against the fretboard of a guitar which will even give you a similar sound.

Immediately the key is released, contact between plunger and anvil is broken, leaving the wool-wound part of the string free behind the anvil free to mute the string. Magnetic pickups are situated at the other end of the string which translate the mechanical vibrations to electrical signals that are fed to the tone circuit preamp via a series of rocker switches.

The Clavinet is, again, really a one sound instrument, less so than the Pianet, but basically there is just that one sound. And what a sound. I love it. And it looks as good as it sounds, a vinyl covered frame with a posh bit of polished wood on the top and a lid that folds towards you. It is quite a heavy instrument but that doesn't really matter, a great machine.

So now we come to this year's model, the Clavinet/Pianet Duo, which as the name implies consists of a Clavinet and a Planet in the same case controlled by the same keyboard. Now, the Pianet activates the reed by the pad at the end of a rod extension to the key, and the Clavinet uses a plunger situated directly beneath the key. So it follows that there is ample room to control both systems with one key. What we have in the Duo is the mechanics of the two instruments identical to their separated counterparts, but with one keyboard.

There are six rocker switches on the front panel, marked Brilliant, Treble, Middle, Soft, CD, and AB. These are situated to the left of the keyboard. The CD, AB switches are connected to the pickups for a wide variety of settings. As required they switch both pickups either singly or in parallel, whereby the polarity of one of the pickups is reversed to cancel overtones or add to them. Thus the AB and CD switches produce the marked tone colours when the switch is pressed in front. If all four are pressed down at the back then no sound is fed through the output.

I found this a bit confusing at first but when there is an instrument in front of you it does become a lot clearer. Underneath the six rocker switches is a volume On/Off control — that's simple at least — and to the right of the keyboard is a damper bar that can drastically alter the envelope of a note.

In addition there is a system of combining the two sections that is rather confusing to the unfamiliar. There are three rocker switches marked, On/Off, 1/2, 1/3; a 4-position rotary switch and the two level sliders, one for Pianet and one for Clavinet. I will not delve too deeply here for fear of losing anyone still with me. There are four sockets on the back of the instrument, marked Pianet, Pianet and Clavinet, Clavinet, and Switch. The 4-position rotary switch assigns which instrument sounds on which part of the keyboard (which is split at the second C from the bottom). The 1/2 and 1/3 rocker switches, when in the 2 and 3 position can be used to alternate between Pianet and Clavinet by means of a footswitch. This seems confusing but, take it from me, you can combine both sections in almost any conceivable way.

The Duo is slightly larger than the Clavinet, but not so nicely finished (no posh wood) and the control panel feels a bit cheap to me. But still, there is no doubt that the combination works. The big question is: Am I better off getting a Duo or the two separate instruments? I really can't answer that for everybody, it obviously depends on the individual, but personally I feel the saving in cost doesn't really warrant the joint purchase. Also if you get fed up with one section of the Duo, you can't replace it without getting rid of the entire instrument.

The Pianet/Clavinet Duo is, however, a good idea and will certainly attract many customers, especially if they want to cut down on the number of keyboards they are carting around. However, I don't think the Pianet T and Clavinet D6 have to worry too much about competition from the birth of their offspring.

r.r.p. (without legs) £715.69/$1950.

Dave Crombie is resident electronic design engineer at Rod Argent's professional keyboard store in central London.