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Cheetah MK5 MIDI keyboard

A master MIDI keyboard for under £100 may sound like a joke to you, especially when it is sold by Boots, but Jay Chapman quickly stopped laughing when he plugged it in. Find out why...


A master MIDI keyboard for under £100 may sound like a joke - especially one bought from your local Boots store - but Jay Chapman stopped laughing once he had unpacked this little beauty and plugged it in. Here's why...


If, over the Christmas hols, you had a really excessive time with the cordon bleu gourmet tasty bits and the odd drop or two of the highly spirited falling down water, you may have needed a quick trip to Boots the Chemist for some Alka-Seltzer... While you were there, you may or may not have noticed the Cheetah MK5 MIDI Keyboard!

For the less domesticated members of SOS's illustrious readership, ie. those who never get dragged around the town centre on endless shopping trips, it may come as something of a culture shock to realise that Boots is not just the Chemists anymore, but also boasts many and various hi-tech delights including records, TVs, hi-fi and personal computers. One of the personal computers that Boots sell is the popular Sinclair (Amstrad?) Spectrum; they also sell some music-making software to go with it. This software may or may not be any good, but it is not shown off to its full potential when all 'playing' has to be done via the Spectrum keyboard. So Boots decided that a real keyboard was required.

This is where Cheetah come into the picture because Boots gave them the job of providing such a keyboard.

A prime requirement would obviously be that the keyboard must be cheap - you're not going to sell many keyboards if they cost four times as much as the computer/software or the same price as the latest Casio all singing-all-dancing wonder machine which has a full implementation of MIDI and folds up into a Transformer/Megadroid Space Station when you get bored with its 96kHz sampling! So, Cheetah had to design down to a price and, therefore, for 'cheap' read 'cheap and nasty', right? WRONG!

Advice on how to read this review: try not to forget that this keyboard sells (exclusively in Boots) for £99.95! If I seem to criticise the MK5 because something is omitted or unsophisticated, think of the price tag: try and get this device in perspective!

MIDI



Boots and Cheetah seem to have had their collective heads screwed on properly and to have kept their minds open during the specification and design of the MK5. The most important point here is that instead of communicating with the Spectrum via some specialised interface that the rest of the world wouldn't understand, the MK5 uses MIDI. Because of this foresight, the MK5 becomes of interest to a much wider purchasing public. After all, a remote MIDI keyboard for £100 is no joke if it does the job, is it?

DESIGN



The MK5 has a five octave, 61 key, C to C keyboard. The keyboard is of typical synthesizer/electronic organ construction, is evenly sprung, has a good feel to it, and has normal size and not miniature keys. The keyboard is housed in a sturdy metal case (with tough plastic end-cheeks) which quite surprised me at this price - for £100 you almost expect corrugated cardboard!

What you shouldn't expect and don't get for £99.95 is the fancier bits and pieces that MIDI offers keyboardwise, such as velocity sensitivity and aftertouch control. There is a Pitch-bend wheel but no Modulation wheel, and nor are there any foot controller inputs for volume or sustain (there may well be such inputs on your 'slave' sound module anyway).

The Pitch wheel is centre-sprung and mounted beyond the keyboard about one octave in from the left, rather than at the lefthand end of it (to save cost on the case width?), and turns left-to-right instead of the more usual front-to-back (to save cost on the case depth?). It could well be possible to add your own strap holders and use the MK5 as a poseur's delight, in which case the left hand could reach around to control the Pitch wheel.

There is only one switch, labelled 'Program/Play', on the front panel which is used to tell the MK5 whether the keyboard information (ie. which keys are pressed) is for MIDI Out (when the MK5 is in the normal Play Mode) or for the use of the microprocessor (Program Mode) within the MK5 itself! This is a fabulous idea: instead of needing several more switches, which would have added to the cost, the MK5 uses some of the normal keys (in the top octave of the keyboard) for its own function control - of which more later.

DISPLAYS: Also on the front panel are four LEDs and a three-digit 7-segment display which are used to indicate the state of the MK5 and give feedback on the operation of the Program/Play switch and the special keys (see Figure 1). At any given moment one of the upper three LEDs is lit to tell you what the 7-segment displays are showing the value of; the fourth LED is lit when the Program/Play button has been pressed to take the MK5 out of normal Play Mode and into Program Mode. The displays will be discussed in more detail when the operation of the MK5 is described below.

INTERIOR: Being of a nosy disposition I opened up the MK5 case to reveal a very neat and tidy interior. There is one circuit board attached to and running the length of the back of the keyboard mechanism and a second circuit board attached firmly to the underside of the right-angled panel that houses all the displays, switches (top surface) and sockets (rear surface). The two boards are connected by a ribbon cable and there are a few flying connections to the switches and sockets; the displays are mounted on the second circuit board.

The overall impression from the state of the inside of the machine is that it was fully thought out before the production run started. This is the way things should be in an ideal world, of course, but often this is where some evidence of the 'nasty' in 'cheap and nasty' would be found if there was any to find. So far, so good!

SOCKETS: There are only two sockets, so even Sun readers should be able to get the hang of using this keyboard!

Firstly, there is a socket which expects to be connected to a 9 volt DC supply. Because the people at Cheetah are thoughtful, a suitable 'power supply in a plug' comes with the MK5. This is a nice touch as they could have saved themselves some money at your expense by leaving you to supply the supply, if you follow my meaning. However, there is no power on/off switch which means that you switch off at the mains socket or simply pull the 9 volt DC plug out of the socket (which the MK5 manual sensibly advises against as it may eventually damage the socket).

There is a MIDI Out socket (5-pin DIN as per the standard) to connect to whatever you want to control - which could be anything from a Spectrum computer (via an interface which you can also buy from Boots/Cheetah) to a Fairlight CMI. With so many devices having all three MIDI sockets (In, Out and Thru), one is momentarily taken aback not to see MIDI In and Thru on the MK5. Other controllers, such as the Yamaha KX88 and Roland Octopad, can have a MIDI In socket to merge an incoming MIDI information stream with the MIDI information generated by the control device itself. This is convenient but not absolutely vital, and this facility has been sacrificed no doubt to keep the MK5's price under the magic £100 figure.

IN ACTION



Having plugged in the power supply and connected the keyboard (via a MIDI cable which you supply) to a suitable sound module, what will the MK5 do for you? In other words: what can you send down the MIDI Out?

KEYBOARD: Playing the five octave keyboard causes MIDI Note On messages with key numbers in the range 36 to 96 to be transmitted. The velocity bytes sent are always set to 64 (ie. mid-range) since there is no velocity sensitivity. In fact, you may need to adjust the sensitivity of the sound module if you previously had it set for a velocity sensitive keyboard which could send velocity bytes larger than 64 (possibly up to the maximum of 127). This is not a fault of the MK5, but is worth being aware of.

Figure 1. Cheetah's MK5 uses the top octave of keys to select functions like Program Change.

When you release a key, a MIDI Note On message with velocity zero is sent in keeping with most keyboards that do not have release velocity sensitivity implemented. Running status is not implemented.

OCTAVE: One of the features accessed via the Program/Play switch is the ability to logically shift the whole keyboard up or down an octave. After pressing the Program/Play switch (when the Program Mode LED lights), the F or E key (in the top octave: C to B) is pressed and the range of MIDI key numbers transmitted becomes 48 to 108 or 24 to 84, respectively. The Octave LED will light and the 7-segment display will show -1, 0, or 1 to remind you of which octave you have selected. The MK5 can then be returned to Play Mode by pressing the Program/Play switch again (when the associated LED goes out).

CHANNEL CHANGE: Unlike certain well-known expensive keyboards, the MK5 can transmit channel-based messages on any of the 16 MIDI channels. The Channel is selected in a similar manner to the Octave selection, using the Program/Play switch followed by the (low) C and D keys to decrement or increment the channel number. The Octave LED lights and the 7-segment display shows the channel selected.

PROGRAM CHANGE: The MK5 can transmit the full range of the MIDI Program Change message and thereby instruct a remote 'slave' device to select any of its programs, 1 to 128. Not all slaves have 128 program stores, of course (as the MK5 manual points out), and you may have to do some mental work (which the manual doesn't point out) if your slave device names its program stores as Banks A to D, 1 to 16 or something equally sexy. This is not Cheetah's fault and it's good to see the full range of 1 to 128 available.

The new Program number is selected in the same way as Octave and Channel are (only using the G and A keys), which is slightly inconvenient if you want to go from program number 1 to 128 because it will take about 20 seconds. You don't have to press the A key 127 times though - you just hold it down and the display increments continuously. When the correct number is displayed, you press the Transmit key (B) to send the Program Change message to MIDI Out.

HOLD: An extra feature is provided by pressing the Program/Play switch when you have the keys of a chord already pressed down. These notes will then sustain without you keeping the keys pressed down which allows you to wander off and play an amazing solo on some other musical gizmo. When you press the Program/Play switch again, the held notes are released. No new notes can be played whilst the MK5 is in Hold Mode.

A small inconvenience here is that although the special keys in the top octave can be held, they will activate their special function as well - this can make life a little confusing. For example, if you change MIDI channel during a Hold then the notes will eventually be turned off, but on the wrong channel - so they won't actually be turned off unless the slave device being controlled is in Omni mode.

WHAT'S YOUR PITCH?



I've left the Pitch wheel until last because it needs a little special attention. Whilst everything else I've discussed on the MK5 has been good, very good or even moderately amazing for a £100 keyboard, or sometimes quite simply omitted (but not unreasonably so given the price), the centre-sprung Pitch wheel shows up as being not quite good enough.

There are two minor problems in that the wheel mechanism (hardware/software) is not totally accurate when self-centring and neither is it stable. In other words, the wheel returns to somewhere near centre when you let go of it and then sends out spurious MIDI messages every so often saying that the wheel has moved when nobody is even in the same room as the MK5 let alone actually moving the wheel!

These problems are minor because both errors average something less than 1% and so are not generally going to be heard; the spurious messages are transmitted perhaps every second or so on average and are unlikely to cause any great harm, although they may waste some valuable storage space in your sequencer.

A more serious problem a rises with the range of values in the messages transmitted when the MK5's Pitch wheel is moved. To keep things simple, let's just consider the most significant byte of the Pitch Wheel Change message, which is all that many sound modules consider anyway.

When a Pitch wheel is hard back/left (lowering the pitch) this message byte should ideally be 0; when hard forward/right (raising the pitch) it should be 127; and when the wheel is centred the last message sent should have the byte set to 64 ie. halfway through the range 0 to 127. On the Cheetah MK5 the ideal range endpoints are not attained or even closely approached. In fact, I found the minimum and maximum values to be 42 and 83 on the MK5 that I tested. That is approximately plus or minus 20 instead of 60 - not too hot!

What does this mean in practice? Well, imagine that you have set your sound module such that moving the wheel fully forward or backwards raises or lowers the note(s) played by a full tone. When you play on your other keyboard, you get the full pitch bend you expect - when you play on the MK5, the same pitch bends are never more than anything like one third effective, with a maximum bend of just 1/3rd of a tone in our example. Unless you re-programme the sound module, of course - in which case you can only control the accuracy of your pitch bends about one third as well as you used to...

I would hope that Cheetah have already spotted this bug and fixed it (a software update should do it). It may be worth checking with the salesman in Boots whether a new EPROM will be made available if the models on sale have not been updated ("I'm not sure, sir - are EPROMs available on prescription?").

CONCLUSIONS



If the MK5 cost £200 I'd say "not bad", although I have the feeling that if I needed a keyboard I would be more likely to put the £200 towards some MIDI-equipped synthesizer in (say) the £350-£450 price range than buy the MK5; this assumes that I would be willing to wait a while (for the pennies to accumulate) to get something that was considerably more versatile.

The fact of the matter, however, is that the MK5 only costs £99.95 - and that really makes a difference. Quite frankly, I was expecting some sort of kid's toy at this price and whilst the MK5 is not (quote) "...the most sophisticated 'slave' keyboard available on the market today," as the blurb in the manual falsely claims, it does represent truly phenomenal value for money and it does work very well (assuming that the Pitch wheel problem is dealt with).

If you want velocity sensitivity, aftertouch, multiple controllers and so on, you will have to look elsewhere; but if you need a simple remote MIDI keyboard and don't want to spend a fortune, the Cheetah MK5 is recommended.

Available exclusively from all Boots stores; price £99.95 inc VAT.

Further information from (Contact Details)


Also featuring gear in this article



Previous Article in this issue

Stepp DG1 Digital Guitar

Next article in this issue

Soundworks S900 Visual Editor


Sound On Sound - Copyright: SOS Publications Ltd.
The contents of this magazine are re-published here with the kind permission of SOS Publications Ltd.

 

Sound On Sound - Feb 1987

Gear in this article:

Keyboard - MIDI/Master > Cheetah > MK5

Review by Jay Chapman

Previous article in this issue:

> Stepp DG1 Digital Guitar

Next article in this issue:

> Soundworks S900 Visual Edito...


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