Casiotone MT-800, Casiotone MT-85 keyboard with key lighting, ROM-Pack & analogue rhythm

Casio MT-800

This was apparently Casio's first keyboard that uses music stored on

(Temperament) of the Keyboard Linking with a Smart Device (APP Function) Using Effects Using the Sound Mode Effects (Hall Simulator/Reverb and Surround) Using a DSP Using Chorus Adjusting Acoustic Piano Sound Characteristics (Acoustic Simulator) Recording Performances in Real-Time Using Auto Accompaniment and Auto Arpeggio Play. The PX-870's award-winning AiR Sound Source includes a four-layer stereo grand piano which comes alive with realistic damper resonance, simulating the entire body of the instrument, not just the strings. The piano also includes key action sounds, key off simulation, adjustable hammer response, and a lid simulator with four positions.

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ROM-Pack cartridges for key lighting feature ('melody guide'). According to a copyright date on the default cartridge, the instrument was likely designed in 1983. Unlike with modern such keyboards, not the keys itself but a row of tiny LEDs above the keys flash up to teach keyboard playing.

In opposite to its predecessor Casio MT-70, the sequencer of this instrument can be programmed by simultaneous live play of main voice and chords. Unfortunately it lacks any edit features which limits its use. Despite this instrument is based on the same chip set like the great Casio CT-410V, it has far less sound variations and even the accompaniment only accepts standard chords. In spite of this the semi- analogue sounds are of high quality and also the analogue percussion sounds are ok.

The original German retail price of the MT-800 in a German Conrad catalogue from 1986 was impressive 999DM (about 500€); a Casio MT-68 cost only the half. A fullsize key variant of the MT-800 was released as Casio CT-810. (It had a silver metallic case shaped like the CT-410V and 5 big knobs to the left of the ROM-Pack slot - despite same hardware, according to CasioNova site it cost in 1984 enormous 899$.)

main features:

• 49 midsize keys
• stereo with separate attachable speakers (of reasonable quality)
• main voice polyphony 8 notes
• 12 semi- OBS preset rhythms {rock, disco, swing 2 beat, samba, tango, slow rock 16 beat, march, swing 4 beat, bossanova, beguine, waltz} selected by locking buttons + select button.
• 12 semi- OBS preset sounds {piano, harpsichord, elec. guitar, pipe organ, trumpet, flute elec. piano, celesta, funny, violin, clarinet, synth. flute} selected by locking buttons + select button.
• separate sliders for main, rhythm and chord volume
• tempo slider
• 'casio chord' switch {off, fingered, on}
• rhythm 'intro/ fill-in' and synchro buttons
• sustain switch
• button for 'stereo chorus' rotary speaker/ leslie simulator (based on a combination of panning and pitch shifting)
• sequencer (550 note steps + 120 chord steps, but only monophonic main voice + standard chords, no edit)
• 'one key chord' button (to step through a chord sequence in sequencer)
• 'melody guide' keyboard play training feature with key lighting (31 red & green LEDs above the keys)
• ROM- Pack music cartridge slot for melody guide and 'auto play' (jukebox mode)
• complex multi- chip hardware:
• accompaniment CPU= 'NEC D930G 017, 8334XK' (80 pins SMD) which produces different multipulse squarewave tones (partly with capacitor envelope) and trigger pulses for external analogue drums.
• main voice sound IC= 'NEC D931C 011, 8329K6' (42 pin DIL) with timbres based on 2 mixed multipulse squarewave tones with different digital envelopes, those are differently low pass filtered through capacitors.
• IC 'HN61364P, 3G1, C61' (28 pin DIL)
• analogue percussion {base, snare, open cymbal, close cymbal, low tom, high tom, woodblock} which apparently uses no transistor noise. The cymbal timbre sounds half- way metallic and resembles the one of Yamaha PS-2, thus it may be mixed from 2 shift register feedback noises.
• tuning & microphone level knobs
• auto power off
• demo melody 'Tanz der Stunden' ('Dance of Hours') by A. Ponchielli
• jacks for AC adapter, speakers, line out, headphone & microphone input

eastereggs:

• selecting from a ROM-Pack cartridge instead of an existing music number the keyboard key 'F' (left next to the lowest number key) loads bizarre sounding note mess into the sequencer, which sounds like repetitive 12 tone music or slow horror movie organ stuff. (This is even mentioned in the manual.) The resulting piece of glitch music depends on the ROM-Pack it was loaded from (and is semi- random?). Because you can play to it and switch rhythms etc., this is quite interesting for tekkno.
• when rapidly switched off and on, the MT-800 sometimes comes up with a sort of distorted ringing mandolin sound, but in this mode none of the digital controls work and the stereo chorus can not be switched off. The rhythm buttons cause rather a sort of buzz or purring, and the sequencer mode switch changes the mandolin ring speed.

modifications:

• polarity protection diode added, power supply jack polarity corrected.

notes:

The MT-800 contains a very complex analogue hardware with stacked large PCBs that resembles much the Casio CT-410V (for technical details and explanations see there); internal speakers likely would not have fit into the crowded case. But the small detachable stereo boxes sound quite nice and even have a reasonable amount of bass although they have only 1.6W. They can be either attached to the back of the instrument case or stand behind it. Unfortunately the only 30cm short speaker cables (with walkman style 3.5mm plugs) limit the placement a lot, and the sharp edged sheet metal stands can easily scratch the instrument case during transport. The same external speakers had also the Casio MT-410V, which is the small case version of the CT-410V. The amplifier produces quite noticeable static noise. A bit odd is that the MT-800 was intended for a 9V DC power supply, while all other small Casios employ 7.5V instead. (Possibly Casio feared that the power amplifier would make clipping distortion at high volume.)

The MT-800 also employs almost the same D931C/ D930G chip set for sound generation like the CT-410V and even has a stereo chorus (but no synthesizer filter). First I thought that in opposite to the latter not the accompaniment IC 'D930G' acts as the main CPU (polls the keyboard matrix etc.) but that everything is controlled by an external CPU 'HN61364P' that handles the sequencer/ ROM-Pack stuff and simulates key press events for the D930G or the like to control the sound indirectly. But now I am not sure anymore; likely the HN61364P is only an external ROM or RAM because it has only 28 pins and on the PCB of my Casio MT-85 it is labelled 'µPD2364EC-074' and Casio chips with 'D23...' are usually ROMs. Also the internal software version of the D930G seems to be different from the CT-410V; while the latter has a 'D930G 011', here it is a 'D930G 017'. Fortunately the MT-800 lacks the annoying muffling capacitor of the CT-410V, which made all sounds very dull. On the PCBs are various trimmer pots; 5 of them control percussion decay speed. (I haven't analyzed the hardware closer yet.)

While the vibrato, reverb, envelope and octave select functions on other instruments were switched strictly by hand, the MT-800 uses only 12 well tweaked preset sounds those switch these features by themselves, which makes many presets sound much more natural than normal default presets on the Casio CT-410V (see there) despite they are still made from 2 mixed and filtered squarewaves. E.g. the 'trumpet' sounds quite realistic now. The sounds 'flute', 'celesta', 'violin', 'synth. flute' are transposed 1 octave up. The 'elec. guitar', 'trumpet', 'flute', 'violin', 'clarinet', 'synth. flute' include a delayed vibrato. The 'sustain' button seems to activate with many sounds rather the 'reverb' effect of the D931C/ D930G chip set than the dedicated sustain effect. (I don't know if the CPU control over the D930G can be circumvented by modifications to regain full manual control over its many sound selection parameters like with the Casio MT-65/ MT-68 or my modified CT-410V.)

The stereo chorus adds a mixture of panning, vibrato and a little chorus to the main voice sound to simulate a rotary speaker; but unlike with the CT-410V, here it can be only switched on or off; it has no speed control and runs slowly with only about 2Hz, which makes of the vibrato a strange mild howl. The intensity of the chorus component seems to be also lower than on the latter, thus the vibrato and panning is most audible.

Unlike the great CT-410V and all my other analogue Casio MT keyboards, the accompaniment of the MT-800 is very restricted since it recognizes only 12 standard establishment chords consisting of each 3 or 4 notes; with any other note combinations it plays only the lowest note as bass (which repeats within 1 octave and thus makes no good manual bass). Despite the very versatile D930G sound chip, this stubborn accompaniment uses always the same plain electronic organ tone for bass and chords, and unlike the predecessor MT-70, it has no arpeggio. Also in organ chord mode (without rhythm) the timbre can not even be switched by pressing different rhythm buttons. The only improvement in comparison to the CT-410V hardware is that this accompaniment does not reduce the main voice polyphony from 8 to 4 notes; likely this was a limitation of the keyboard polling algorithm in the D930G, which is circumvented by the external CPU. The accompaniment always uses the stereo chorus, which gives especially the organ bass tone an interesting droning timbre (a bit like a propeller aeroplane). This analogue bass sounds soft and pressureful - a bit like a church organ.

The analogue percussion sounds much like on Casio CT-410V (see there), but the rhythms seem to be also controlled by the main CPU, because there are e.g. 2 different swing rhythms, those don't exist within the preset rhythm of the D930G chip. The new rhythm set was likely standardized for ROM-Pack instruments, because they all include the same rhythm names although their percussion sounds different.

The sequencer is less awkward than on Casio MT-70, but it can not be edited anymore and thus is of little use (only melody and chord track can be erased separately). Also the 'one key play' buttons of the latter are gone; only a 'one key chord' button permits to play recorded chords one by one. Generally the MT-800 appears despite its external stereo speakers far less professional than the MT-70, because it has not only less main voice sounds and no display, but permits way less user controllable variations of given presets and behaves in some ways similarly stubborn than Casio's later ToneBank instruments. Quite interesting is that this instrument loads any played songs from the ROM-Pack cartridge first into the internal sequencer RAM (takes about 3 seconds; smaller keyboards like the Casio PT-82 don't do this). Beside chord, rhythm and monophonic main voice, the ROM-Pack musics contain a 2nd monophonic melody voice (called 'obligato' by Casio) which is apparently stored on an additional sequencer track. Unfortunately this track can not be recorded by hand (possibly a button can be added as an easteregg for this). ROM-Pack musics also contain instrumentation and rhythm changes, those can also not be recorded manually too. For play training, chord and melody track can be muted separately, but these buttons don't work while the sequence is playing. Great is that you can play (up to 4 note polyphonic!) while the sequencer is played back. The 'obligato' voice volume can be only set together with the rest of the accompaniment; I badly miss a separate volume control for it because it tends to be too quiet.

The MT-800 seems to have been indeed the first ROM-Pack keyboard, because its behaviour has various glitches and is less elegant than later such instruments (e.g. Casio PT-80 and PT-82). These smaller instruments indicate e.g. with a walking light on the LED row above the keys that the user shall select a song number from the cartridge, and a click indicates that an empty number was selected, while a correct number starts that song. With the MT-800 instead there is only a static light above the key with the last selected song number, and during selection even the note of pressed keys still sound. (You can even play polyphonic on the keyboard in this mode, which was certainly not planned by Casio.) After selection you have to press 'memory start' to load the song (possibly a safety measure because it overwrites the sequencer content). Selecting a non- existing song number or the rightmost key ('demo') selects the built-in demo song 'Tanz der Stunden'. On later instruments the rightmost key plays all songs on the cartridge in a sequence. Selecting instead of a melody number the keyboard key 'F' (left next to the lowest number key) loads a lot of bizarre sounding (semi- random?) note mess into the sequencer. Other glitches include that after connection to supply voltage there is also mess in the sequencer and often the 'sustain' or 'stereo chorus' effects are active despite their locking buttons are not pressed (press them to fix this). But like with later ROM-Pack instruments already here 2 lights indicate the keys for the current and next played note (current = lit, next = flashing), and you can select the melody guide either to wait for the player (press 'start' to begin) or to continue with its programmed tempo (press 'memory start' to begin). You can also switch the LED row off by pressing 'cancel' before starting the melody guide; thus basically all 4 melody guide levels of the Casio PT-82 (but not the 'rating' feature) already exist on this early instrument. While a song plays from the ROM-Pack, you can even switch the rhythm off and do many other manual things those with later ROM-Pack instruments don't work anymore.

My Casio MT-800 came with the default ROM-Pack RO-201 'Fun With Your Casio Keyboard', which contains 15 songs. Unlike my other ROM-Packs it has a shiny sheet metal bottom instead of the usual black plastic one. It is quite strange that this old instrument was shipped with a 15 song cartridge, while later Casio keyboards came with ROM-Packs with each only 4 songs, despite the price of ROM capacity certainly didn't increase over the years. In the manual of this cartridge several other ROM-Packs are advertised with also each >10 songs. With my MT-800 I also got the ROM-Pack RO-253 'Pop/ Rock'.

Predecessor of the MT-800 was the Casio MT-70 (with barcode pen instead of ROM cartridges). Successors were likely the MT-820 and MT-88 (both similar, with internal speakers). In eBay announces some people claimed that you could also save own musics from the sequencer onto the ROM-Pack 'diskette', but I guess this was just a wrong description; I have tested to insert the RAM-Pack RA-1 of my PT-50 into the MT-85 (hardware like MT-800), but it gets simply ignored. The likely last non- toy Casio keyboard with ROM-Pack slot was the Casio CT-840.

Casio MT-85

This rare keyboard was basically a re- released mono version of the wonderful Casio MT-800; it only lacks the 2nd speaker and stereo chorus and has a boring case style, but is otherwise technically identical.

In my German MT-85 manual there is even a typo somewhere that calls the keyboard 'MT-800'. The manual claims that it was packaged with the ROM-Pack RO-201 (like with MT-800) while my used specimen came with a RO-551. A brown MT-85 version was released as Casio MT-86 (seen on eBay).

different main features:

• mono with built-in 8cm speaker (sounds bright and a bit bassless)
• no stereo chorus circuit
• no jacks for microphone & speaker output
• complex multi- chip hardware:
• accompaniment CPU= 'NEC D930G 018, 8438XK, Japan' (80 pins SMD)
• main voice sound IC= 'NEC D931C 011, 8437KY, Japan' (42 pin DIL)
• IC 'HN61364P, 4M3, C61, Japan' (28 pin DIL, additional PCB label 'µPD2364EC-074')
• RAM?= 'HM6168HLP-70, 8443, 00001NN0, Japan' (20 pin DIL)
• hybrid= 'S648F18S, 4D011'
• hybrid= 'S645F16S, 4D0111'
• hybrid= 'S430F17S, 4D0111'

eastereggs:

• different 'mandolin bug' than Casio MT-800; when the AC-adapter output plug is re-plugged rapidly, the instrument sometimes makes bizarre purring digital main voice sounds. The rhythms behave normal here; likely only wrong sound synthesis parameter are loaded into the sound chip, because after switching to a different preset sound everything sounds normal again.

modifications:

• polarity protection diode added, power supply jack polarity corrected.

notes:

To simplify the complex MT-800 hardware and make the speaker fit into the case, Casio here integrated some of the discrete components (mainly analogue percussion?) into 3 black hybrid modules. Thus unlike the MT-800 this keyboard contains no stacked daughter PCBs anymore but only 2 (still large) main PCBs. (Similar hybrid modules were used in Casio KX-101.) Interesting to mention is is that like with MT-800 and MT-85, Casio later also re-released their stereo ROM-Pack keyboard MT-820 as the mono version Casio MT-88, which was also only missing the stereo chorus and a 2nd speaker. Strange is that the accompaniment CPU of the MT-85 has the type number 'D930G 018' ,while the MT-800 had a 'D930G 017', thus it may contain a different software version despite the user interface behaviour of both instruments is identical. The IC 'HN61364P' has the PCB label 'µPD2364EC-074', which may be a relative of the 'D23C64EC ...' ICs in Casio MT-500 and MT-520.

removal of these screws voids warranty...

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Unprecedented Natural Reproduction of the Rich Expressive Power and Resonance of an Acoustic Piano

Simulating the Delightfully Delicate Reverberation and Rounded Resonance Associated with Pianos

The characteristics of CASIO’s newly developed Multi-dimensional Morphing AiR*Sound Source reflect thorough attention to detail in expressing the rich, resonating tones inherent to the piano. The capacity of the installed memory has been expanded to achieve a longer sampling duration and enhanced waveform data quality. The temporal changes in tone that create sound you would expect only from a piano, beginning with the initial sound and leading into a beautiful extension until the sound eventually vanishes, are reproduced naturally. Even the length of the reverberation can be controlled at will by the player by adjustments in touch, as with an acoustic piano. Seamless variations that respond continuously to the power behind each stroke, not only in terms of volume but also in terms of the nuances of the sound itself, range from a fine, gentleppp(pianississimo) to an intense, powerfulfff(fortississimo). All 88 keys in corporate a stereo resonance simulator, more over, that reproduces the string sounds of a grand piano remarkably realistically. The pleasure of listening to acoustic changes can be obtained by opening the grand piano-like lid installed on high-end models (PX-860), which place a particular focus on sound output quality. These developments represent an unprecedented evolution of the digital piano’s expressive power in the areas of both sound and resonance.

New sampling technology pursuing the ultimate expressive power of an acoustic piano

Sound source memory expanded
to reproduce original sounds
more naturally!

The acoustic level achieved by a digital piano is determined by the capacity of the memory that stores sounds after sampling. A new high-capacity memory, boasting a capacity in excess of approximately three times our previous models (converted linearly), is installed for the Multi-dimensional Morphing AiR Sound Source. The waveform data sampling capacity has increased dramatically, enabling natural reproduction of the delicate changes in waveforms associated with concert grand pianos. The sound quality and resonance have achieved astonishing evolution, realizing an ability to produce simultaneous sounds comprising up to 256 notes in high-end models (PX-5S, PX-860).

Digital pianos normally compress and record sound waveform data in their built-in memory. This data is then expanded and played back when recalled. As in the case of compressed audio data such as MP3, therefore, the played-back sound simply cannot avoid deterioration with respect to the original sound. But the advanced Lossless Audio Compression technology adopted for CASIO’s Multi-dimensional Morphing AiR Sound Source has made it possible to reproduce sounds without this deterioration of the original sound quality. This permits enjoyment of musical performances with acoustics that are immeasurably closer to natural piano sounds.

88-key stereo resonance simulator reproducing a deep acoustic piano resonance

The sound produced by an acoustic piano is not only the sound associated with the keys that are struck. Other strings with frequencies closely associated with those producing the sounds resonate as well, adding their sound to give the music a uniquely rich resonance. In ordinary digital pianos, this string resonance effect is reproduced virtually with strings. The Multi-dimensional Morphing AiR Sound Source takes a different approach, however, by adopting a String Resonance system incorporating a stereo resonance simulator for all 88 keys. The resonance of the 88 keys is reproduced completely and naturally. The resonance realized by playing a single tone is differentiated from that realized by playing a chord to reproduce the resulting variations in resonance in a natural manner. This even enables players to achieve varying resonances, controlling them at will by the strength of their touch, and thus to realize performances with the unique expressiveness of an acoustic piano.

The external designs of the PX-860 model feature a lid on top that can be opened and closed. Opening the lid enables the pianist to play music with abundant dispersed sound, much like that produced by a grand piano with its lid open.

With an acoustic piano, the strings’ vibrations are amplified by the soundboard, generating sound from throughout the instrument. CASIO's new equalizing system imparts a unique sensation of three-dimensional depth and creates a natural sound space. It represents yet another advance in the pursuit of optimal sound and playing pleasure.

The deep, beautiful resonance resulting from the use of a damper pedal is also reproduced naturally by a stereo resonance simulator installed on all 88 keys, an approach that differs from conventional simulated reproduction employing effect processing. The attention to detail goes so far as to simulate the resonance created by the lifting of the dampers themselves when the pedal is pressed. A continuously variable system*2has been adopted for the damper pedal, moreover, reproducing even the subtle changes in reverberation that occur in response to the delicate pressure exerted by partial pedal operation. This enables players to employ pedal operation to achieve gracefully expressive performances.

• *1PX-860 models offer 4 adjustment levels. PX-5S model offers 16 adjustment levels.
• *2PX-860 only

The volume and timbre of sound produced by a grand piano change depending on the degree to which the lid is open or closed. The Lid Simulator simulates these acoustic effects digitally. Pianists can select among four settings for opening and closing stages and enjoy playing music with the piano sound effect of their choice.

• *PX-860 only
• *The PX-5S's Lid Simulator serves as a DSP.
• *The Lid Simulator setting value remains unchanged, regardless of whether the lid on the piano body is open or closed.

The 4 stages of a grand piano’s lid opening and closing have been investigated and imitated.

The difference between the sound structures of a grand piano and a digital piano appears as a difference in timing, from the moment the instrument is played until the sound is audible. The new Tri-sensor Scaled Hammer Action Keyboard II responds by incorporating a system with three sensors that detect keystrokes sequentially. This permits minute variations in the time between detection of a keystroke and sound production, depending on the speed of the keystroke. The sensor system also enables a sound to be produced continuously, even when the key has not fully returned to its resting position, a feature assuring excellent playability when the same note is struck repeatedly. Also as in a grand piano, moreover, the action mechanism relies solely on the weight of the hammer, with absolutely no springs employed, thus providing both a definite playing response and a smooth touch. The keys become progressively heavier as the sound becomes lower and progressively lighter as the sound becomes higher, faithfully simulating this characteristic of a grand piano.

80s Casio Watch

The sizes of the hammers that strike the strings differ among the various key blocks in a grand piano. The sounding timing consequently varies subtly, even when keys are struck with the same strength. The new keyboard system carefully reproduces these differences in sound production timing from one register to another. It even simulates the differences in sound production timing according to the force with which a key is struck.

The lengths of the reverberations and expressions a piano produces vary depending on the speed at which players release their fingers after touching the keys. The new keyboard system incorporates a Key Off Simulator that reproduces these nuances resulting from key release naturally. Authentic reverberations that feel just like those of a grand piano are expressed as a result.

The simulated ebony and ivory keys offer the luxurious feel and texture as well as the smooth touch of a grand piano keyboard. The minutely detailed crimp surface finish inhibits finger slippage due to sweat and gives the sensation of a perfect fingertip fit, even when playing for extended periods.

High-level performance functions that enhance playing pleasure

The Hall Simulator function simulates the differing acoustic characteristics of world-famous concert halls, from pure reverberation with outstanding tonal transparency to free-spirited, dazzling reverberation. An advanced equalizing system assures the pianist’s full enjoyment of vital piano sound.

High-quality audio data recordings of 10 live orchestra performances are installed. Pianists can play along with the recordings and enjoy the feeling of participating in a magnificent performance. Musical scores of the concerts are bundled.

• *PX-860 and PX-760 only

Various functions supporting lessons and performances

Pianists can choose one of two recording functions, an audio recorder or a MIDI recorder, depending on their purpose.

Pianists can use the audio recorder to record their own performances on USB flash memory (sold separately).Since the recording employs the WAV file data format, performances can be played back*1 with CD sound quality on either the instrument itself or another device such as a PC, audio system or portable music player.*Playback possible on WAV file compatible devices.

80s Casio Keyboard

• *PX-5S, PX-860, PX-780M and PX-350M only

Pianists can also use the piano’s built-in memory to record their performances. The MIDI recorder supports recording of separate tracks, allowing pianists to complete compositions that are difficult to play with both hands by recording the right-hand segment first and then recording the left-hand segment on top of it.

• *What is MIDI?
• The letters MIDI stand for Musical Instrument Digital Interface, which is the name of a worldwide standard for digital signals and connectors that makes it possible to exchange musical data between musical instruments and computers (machines) produced by different manufacturers.

List Of Casio Keyboards

The layer function enables pianists to overlap two types of tones, while the split function lets them separate tones into lower and higher blocks.

• *Except model PX-5S

The keys to the left and right of center on the keyboard can be set to the same tonal range. This Duet Mode is convenient when two players, such as a parent and child or a teacher and student, practice together.

• *Except model PX-5S

The metronome comes in handy when practicing the piano.

• *Except model PX-5S

A variety of built-in musical pieces can be played back for either listening pleasure or use in piano lessons. (Except models PX-5S and PX-350M. Collection of musical scores bundled.*)

• *Some musical scores may not be included due to copyright issues.

The operation lock feature is used to lock the button operations to prevent unintentional setting changes.

Auto power off is a practical feature that prevents wasteful electricity consumption by shutting down the power automatically when no operation has been conducted for a certain period of time.

• *Illustrations and graphs are conceptual images for reference purposes only.