Magazine Archive

Home -> Magazines -> Issues -> Articles in this issue -> View

Organ Talk

A look at Casio's portable keyboards and their applications for the home organist

Article from Electronics & Music Maker, March 1983

Portable keyboards and their applications

Casio MT-70.

If anyone ever tells you that running a Bar Code Reader over the end of a packet of PG Tips will produce 'Tea for Two', forget it! Nine distinct instructions are coded into binary for each block of information for pitch, length and chords in Casio barcode music. Only one of these is actually concerned with data, the others covering instructions for headers, line numbers, start and end marks etc. So you won't crack the code that easily!

The Editor reviewed Casio's CT-701 keyboard in January 1982 when that model was the top of their keyboard range. I tried it out at the time to see how it sounded through an organ system — with External Tone Cabinet and Leslie 145. I found the results most encouraging, many of the voices being indistinguishable from organ tones when treated to the Doppler effect.

Casio have come a long way in a short time in the electronic music field and since the review of CT-701 was published new keyboards have been introduced: indeed, a week before writing this article details of 1983 models were released.

Ten years ago, many of us were beavering on monophonic synthesiser projects — most of which will now be gathering dust. Polyphonic keyboards of various types have taken over and those based on digital circuitry have the great advantage that they stay in tune to a degree that can be tolerated.

Third manual

Among the recent models, two Casio keyboards offer interesting possibilities to those who are looking for a 'third manual' to place on top of the organ console. Models CT-501 and MT-70 share similar specifications and are scaled down versions of the CT-701, but are far less expensive despite retaining nearly all of the larger keyboard's facilities.

CT-501 has four octaves of full sized keys, is mains-operated and has provision for external control of volume and sustain. MT-70 is a four-octave mini keyboard and can be used with internal batteries or with a mains adaptor but volume and sustain can only be controlled from the top panel. As batteries are required to keep the RAMs alive when not in use, the MT-70 is best used with a mains adaptor. Both instruments are supplied with music in both manuscript and bar code, an operation manual and BarCode Reader.

I find the MT series of mini keyboards completely playable despite being a little smaller than usual: though shallower, they are not unlike those on a piano accordion. An octave of the MT-70 keys (C to C inclusive) measures 6½", against 7.3⅜" for a full size keyboard. Thus this model is extremely compact (just 25" long) and sits neatly on top of the organ.


The Editor has described the programmable keyboard as a valuable teaching aid — and I agree with his comments wholeheartedly. The household musician often wishes to involve the family in learning to play so that the keyboard may have a dual function in due course.

CT-501 and MT-70 have their controls divided into four groups:

Auto Accompaniment:

  • Off, fingered. Casio Chords.
  • Rhythmic, Arpeggio accompaniment.
  • Chord Memory on.
  • Octave down.

Auto Rhythm:
  • 10 Rhythm patterns.
  • Start/stop.
  • Synchro start.
  • Fill in.
  • Tempo.
  • Accompaniment Volume.

  • 20 Preset voices indicated by LCD.
  • Vibrato off, on, delayed.
  • Sustain off, on.

Memory Play:
  • Mode Selection switch.
  • Memory Play.
  • Back, Forward, Delete, Reset, Repeat.
  • Return 1, Return 2, Accomp. Start (with LEDs).
  • Rest, End (with LEDs).
  • One Key Play.
  • LCD of chord symbols and memory steps.

The back panel has sockets for headphone, line out, Bar Code Reader and a rotary control for fine tuning (+/- 50 cents or 1/4 tone). MT-70 has an input socket for +7.5V and CT-501 connections for volume and sustain.

Output voltage is 1V maximum - affected by an overall volume control - so some attenuation may be necessary when fed into an organ or hi-fi system. Output impedance is 3k (MT-70) and 4.7k (CT-501) and power consumption 4W and 26W.

Casio CT-501.

The Organist

If it is intended to amplify the keyboard through the organ's circuitry, it is best to avoid including reverberation as the keyboard's sustain is sufficient in itself and its rhythm unit would not benefit.

The MT-70 is best used with a PSU to provide +7.5V as, despite 5 D-size cells, the unit consumes some 350mA. The required power might be found from within the organ, dropping and regulating to the required voltage by power transistor and Zener or variable voltage regulator. Batteries will still be required, of course, to maintain memory while not in use.

Having set up the keyboard, there are several ways it can be used with the organ. With both Casio Chord and Mode Selection switches off, the complete four octave compass is available for use with one of the 20 voices with Vibrato and Sustain variations. In this mode it becomes the 'third manual' and its own rhythm unit may be used independently; Synchro Start is still operative when any key of the lower 1½ octaves is pressed. Piano and Vibraphone (with Sustain) complement organ tones admirably, and Chorus, Funky and Jazz Organ are good additions to the line-up.

The experienced player can also use the keyboard as the second man. Music can be entered into memory via the keyboard, where storage capacity is 345 melody steps and 100 bars of chords: notes are stored first, then chords and finally the note durations. The memory can then be played back complete, melody only or as accompaniment only.

Replay of the complete memory might be accompanied on the organ's lower manual with interjections on the upper. With partial replay, the organ could supply the missing part. There is plenty of scope for experiment as programming can include tacit periods and lead-in notes. First and second repeats can be programmed into the melody line, but chord sequences must be entered in full.

The Family

Anyone new to music will find one of these keyboards a great asset. The starting point may well be to set the instrument as a single manual keyboard for practice of slow and steady sight-reading. Here is where the headphone facility will be useful - and possibly the PSU fora long practice session.

Progressing to the Automatic features calls for a decision on the part of the musical 'boss'. Should the beginner use Fingered or Casio chords? Three Casio chords can be produced - Major, Minor and Dominant Seventh. However, seven types of Fingered chords will be recognised and indicated on the LCD - Major, Major Seventh, Augmented, Minor, Minor Seventh, Dominant Seventh and Diminished Seventh.

When the Keyboard is split (by setting to Fingered or Casio Chord) the chord symbol is indicated and the beginner will see if the fingered chord is correct or not. This valuable aid will soon enable the beginner to memorise commonly used chords - all of which are shown in the music book. In this mode, the upper 2½ octaves of 'solo manual' may be shifted by the Octave Down slider.

Bar Code scores can be entered into memory (or the matching manuscript music entered from the keyboard) and used to improve sight reading. Auto-Play allows the music to be followed visually (at any speed and rhythm). The Melody Guide feature shows the player which keys to press by means of LEDs above the playing keys. Alternatively, One Key Play allows the recall of each note of the manuscript score with rhythm accompaniment. As 8-note polyphonic instruments, these keyboards still leave one or two notes to spare when Auto-Playing so that the beginner can attempt to harmonise - perhaps by playing along in thirds.

Each time a new composition is put into the memory, the previous one is erased. Owners of home-computers will realise that there should be a way of storing on tape. Well, Casio have thought of this aspect and it is a feature of their new PT-30 programmable keyboard: no doubt it will be added to higher priced models in due course.

Although I have suggested using the programmable keyboard with an organ, its compact nature makes it an admirable proposition where space does not allow for a piano in the home.

Also featuring gear in this article

Previous Article in this issue


Next article in this issue

Tokai Flying V

Publisher: Electronics & Music Maker - Music Maker Publications (UK), Future Publishing.

The current copyright owner/s of this content may differ from the originally published copyright notice.
More details on copyright ownership...


Electronics & Music Maker - Mar 1983

Feature by Ken Lenton-Smith

Previous article in this issue:

> Videomusic

Next article in this issue:

> Tokai Flying V

Help Support The Things You Love

mu:zines is the result of thousands of hours of effort, and will require many thousands more going forward to reach our goals of getting all this content online.

If you value this resource, you can support this project - it really helps!

Donations for July 2024
Issues donated this month: 14

New issues that have been donated or scanned for us this month.

Funds donated this month: £20.00

All donations and support are gratefully appreciated - thank you.

Magazines Needed - Can You Help?

Do you have any of these magazine issues?

> See all issues we need

If so, and you can donate, lend or scan them to help complete our archive, please get in touch via the Contribute page - thanks!

If you're enjoying the site, please consider supporting me to help build this archive...

...with a one time Donation, or a recurring Donation of just £2 a month. It really helps - thank you!

Small Print

Terms of usePrivacy