Casio 80s Keyboard Simulator

Casio keyboard instrument user's guide (44 pages) Summary of Contents for Casio CPS-85 Page 1 CPS-85 TRANSPOSE DIGITAL EFFECT TONE MEMORY POWER VOLUME HARPSI- PIPE PIANO 1 E. PIANO 1 STRINGS SELECT SONG A CONTROL DEMO CHORD ORGAN PIANO 2 E. PIANO 2 VIBRA- JAZZ SYNTH- SONG B RECORD STOP START PHONE STRINGS ORGAN CPS-85. Casio electronic musical keyboards were first manufactured in 1980 and continue to be made by Casio today. The original Casiotone line was abbreviated to CT in the mid-1980s but has continued to feature full-sized keys. MT and PT lines typically feature mini keys and the VL line features push-button keys. A Grand Revolution. The new PX-780 represents a significant step in the continuing evolution of the Privia digital piano line. A combination of a new keyboard action and a powerful new sound engine provide a new level of detail, nuance and expression for a superior grand piano experience in the lightweight and stylish design that Privia is known for.

With the PX-S1000, Casio opted to use a different key action, one that is designed to fit the slimmer chassis. Casio calls this the Smart Scaled Hammer Action. To be clear, these are no longer triple sensor actions; they are two-sensor actions instead.

Sound

Three Legendary Pianos
Their individual character and tone faithfully recreated

CELVIANO Grand Hybrid reproduces even subtle nuances of the world’s most respected pianos. Three pianos that originate in Berlin, Hamburg and Vienna were chosen for this project. Casio has painstakingly researched and analyzed the unique characteristics of each piano. CELVIANO Grand Hybrid delivers brilliant sound of these pianos reproduced with Casio’s advanced technology. It will provide the experience of owning three of the finest pianos on earth.

A balanced, elegant sound. Ideal for playing impressionistic music. Notable for its clear, ringing tone across the entire range.

A brilliant, rich sound. Loved by pianists for its wide range of expression. Well suited for various playing styles and genres.

Noted for its impressive low range. Great for both soft and vigorous playing with its warm tone. An ideal instrument for music from the classical period.

The Berlin Grand sound was developed in collaboration with C. Bechstein. Casio sought a clear, balanced and elegant sound for CELVIANO Grand Hybrid. D282, C. Bechstein’s ultimate masterpiece, is the model Casio intensively studied to achieve the goal. Mr. Albrecht, Service Director and Master Piano Maker at C. Bechstein, visited Casio R&D to supervise the sound development process through the final modification.

Since Carl Bechstein founded the Pianoforte production facility in Berlin in 1853, the name C. Bechstein has stood for the highest class of upright and grand pianos. C. Bechstein pianos have been appreciated by many famous composers and artists for their finest quality of sound and touch for many years. In the 21st Century, C. Bechstein is still recognized as one of the world’s leading piano manufacturers.

More natural sustain for more beautiful chord resonance. More sensitive expressiveness for pianissimo sounds, especially when playing extremely softly.
The CELVIANO Grand Hybrid incorporates AiR Grand Sound Source, a system using Casio’s state-of-the-art sound technologies. It includes many impressive features. Multi-dimensional Morphing delivers smooth changes between soft and strong playing. Acoustic Simulator reproduces the characteristics of sounds produced by acoustic grand pianos. The authenticity generated by the AiR Grand Sound Source ensures a pure piano experience.

• AiR ＝ Acoustic & Intelligent Resonator

On an acoustic grand piano, the volume and quality of sounds change from the time the keys are struck until they die away. Casio’s Multi-dimensional Morphing technology enables natural, smooth transitions in sound volume and tone based on the power of the keystroke. This technology contributes to more expressive performances.

The various types of resonance in a grand piano are crucial to the playing experience. The CELVIANO Grand Hybrid incorporates String Resonance, which exposes the harmonic relationships between various strings when keys are struck. Also Damper Resonance reproduces the resonance occurring when a damper pedal is pressed. Casio’s Resonance System reproduces the resonance of both the strings and sound board of a grand piano by selecting, controlling and synthesizing according to performance conditions.

A grand piano also generates several types of mechanical sounds, which are an important part of the playing experience. Casio has sought to provide a more realistic simulation by reproducing the sounds of these mechanisms. Three types of operating sounds are included, and the volume of each can be set independently or turned off.

• Damper Noise, Key On Action Noise and Key Off Action Noise

The lengths of the lingering sounds produced by a grand piano vary depending on the speed at which players release their fingers after pressing the keys. In a similar fashion, Casio’s Key Off Simulator controls the length of these sounds based on the key’s release speed and delivers a natural decay of the sound. This enables players to express delicate nuances when playing staccato and legato.

The timing of a grand piano’s sound varies subtly depending on which keys are being played, even when the keys are struck with the same force. To achieve optimal authenticity, Casio has installed appropriate settings for each of the three grand piano tones. The sound production timing can also be adjusted to suit the player.

By continuously sensing and detecting the position of the damper pedal, Casio’s Grand Pedal System enables fine-tuning of the damping volume and note length depending on the degree of pedal depression. In addition, the Half Pedal Position function permits adjustment of the depression position at which the damping effect comes into play according to the player’s preference. For performances which utilize the soft pedal, the change in volume and characteristics of sound is extremely natural where the player can enjoy a wide range of expression when playing softly.

More powerful, dynamic playing expression from lows to mids to highs, thanks to the superlative sound delivered by an upgraded downward-facing main speaker, with especially improved bass
Casio has developed a new dedicated speaker system for the CELVIANO Grand Hybrid that reproduces the characteristics of sound emanating upwards and downwards from an acoustic grand piano. This enables powerful and dynamic expression from rich, stately bass to bright mid-high sounds. The four-channel audio system incorporates six speakers, carefully positioned in a structural design that releases sound outward from the interior of the body. The system delivers the same sound field experience a player would enjoy while playing an acoustic grand piano.

The CELVIANO Grand Hybrid’s design includes a top panel that can be manually raised and lowered. The lid’s position not only physically affects the sound coming from the upper speakers, but also works in conjunction with the “Lid Position” setting to accurately duplicate the characteristics of the adjustable lid on an acoustic grand piano.
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.

• The Lid Simulator’s setting value remains unchanged, regardless of whether the piano’s top board is open or closed.

Twelve types of Hall Simulator are included; each one based on careful analysis of the acoustic characteristics of a world-famous concert venue. Each space has a total of four Listening Position settings. For example, the pianist can simulate the experience of hearing the piano from a seat in the audience, as opposed to the playing position.

Volume Sync EQ is especially useful for quiet playing at home and other times when you want to keep the speaker volume low. This function balances the sound at low volumes by adjusting the sound quality in the low and high registers. The result is a constantly pleasant playing experience, no matter where the volume is set.

Headphone Mode automatically creates a spacious sonic image while wearing headphones, recreating the feeling of playing an acoustic piano. With the experience of wearing headphones significantly enhanced, pianists can enjoy playing naturally and feeling the sound field of a traditional grand piano.

Touch

Your performance demands authenticity
It begins at the first touch

The player’s movement is transformed into music with many important factors. The most tangible factor is the keys. CELVIANO Grand Hybrid delivers authenticity from the first touch. The revolutionary Natural Grand Hammer Action keyboard is made with high-quality wooden keys. Its mechanism incorporates the hammer action that follows the same path of motion as in a grand piano. When the lid is lifted, you can see the hammers in motion through a clear panel as you play. Going beyond a standard acoustic mechanism, this action allows faster note repetition than acoustic pianos, while maintaining a true piano touch.

Natural Grand Hammer Action Keyboard

For an authentic piano touch, Casio has developed a new keyboard system called the “Natural Grand Hammer Action Keyboard”. This keyboard system features full-length wooden keys as well as hammers that follow the same path of motion as in a concert grand piano. CELVIANO Grand Hybrid features keys that are manufactured using exactly the same materials as acoustic grand piano. Careful attention is paid not only to finish of the surfaces of the keys but also to the quality of the wood employed for the key beds. This combination of an outstanding action mechanism and superior-quality key materials further enhances the sensation of playing an acoustic grand piano.

1. Original Tri-Sensor action mechanism

The core of CELVIANO Grand Hybrid’s keyboard performance is created by Casio’s proprietary action mechanism. This mechanism includes a hammer movement modeled from a grand piano and three sensors, which accurately capture a performer expression from the keys. Since there are no physical strings, Casio’s action is able to exceed the performance characteristics of a grand piano, providing superior playability that enables pianists to perform such actions as trills and repetitive notes with ease.

2. Keyboard surface materials

The use of acrylic for the white keys and phenol for the black keys — the same materials that modern grand pianos employ. This creates a welcome and familiar touch. Pianists will feel comfortable and confident on the keys of CELVIANO Grand Hybrid.

Casio 80s Keyboard

3. Fulcrum distance from keys

The position of the fulcrum with respect to the keys is exactly the same as with a grand piano. This contributes to stable playing performance, since the touch is never heavier or lighter depending on the position at which a finger strikes a key.

The keyboard is constructed using Austrian spruce of the finest quality. Careful attention is paid to drying and processing of this high-quality material before keyboard construction begins.

The keyboard is developed to ensure superior piano performances by considering each of the 88 keys independently and how they perform together as a single unit. Perfection of the keyboard is pursued as well through attention to such factors as load changes and key return speeds.

Beyond simply detecting the overall force of a key being played, the entire travel of the key is precisely modeled after the behavior of a grand piano

Casio’s technology for enhancing control of strokes between soft and strong playing

The player’s movement is transformed into music with many important factors. The most tangible factor is the keys. CELVIANO Grand Hybrid delivers authenticity from the first touch. The revolutionary Natural Grand Hammer Action keyboard is made with high-quality wooden keys. Its mechanism incorporates the hammer action that follows the same path of motion as in a grand piano. When the lid is lifted, you can see the hammers in motion through a clear panel as you play. Going beyond a standard acoustic mechanism, this action allows faster note repetition than acoustic pianos, while maintaining a true piano touch.

[ Natural volume changes and wide expression ]

With the new GP-510BP and GP-310BK/WE, they are designed with high precision to ensure that changes in the dynamics pressure from the player’s fingers are similar to that of a grand piano. As a result of repeated simulations and fine adjustments, all with the aim of perfecting the relationship between volume change and key pressure, players can naturally control the sound volume across a wide spectrum of tonal colors between Pianissimo and Fortissimo as if playing an acoustic grand piano.

[ Precision keyboard return speed ]

Casio has conducted a thorough study of the speed at which grand piano keys return to their normal position after they are struck. This research has finally led to the development of a keyboard action with a consistent return speed and stable responses across the range of the instrument.

Experience

The Grand Hybrid experience goes far beyond playing piano

[ Concert Play ]

Playing with an orchestra is an extraordinarily thrilling event. Concert Play feature demonstrates orchestral performance for a pianist to enjoy an experience of playing as a soloist accompanied by a full orchestra. 15 pieces of music are built in. When you practice, a convenient playback function offers capabilities of play, pause, fast-forward, rewind and A-B segment repeat. Using a Slow Mode, the tempo of these pieces can be slowed to 80% of normal speed as needed.

Concert Play Preset List

1. Piano Concerto No.1 Op.23 1st Mov.
2. Prelude “Raindrop”
3. Symphony No.9 “An Die Freude”
4. Je Te Veux
5. Vltava (Má vlast
6. Canon
7. Sonata Op.13 “Pathétique” 2nd Mov.
8. Chanson Triste
9. Jesus, Bleibet Meine Freude
10. Tableaux d’Une Exposition “Promenade”
11. Sonata K.331 1st Mov.
12. Polovetzian Dance (Prince Lgor)
13. Piano Concerto No.20 K.466 2nd Mov.
14. Violin Concerto Op.64 1st Mov.
15. Melody In F

Versatile features

Audio Recorder

CELVIANO Grand Hybrid pianos have the ability to record performances on USB flash memory available on the market as stereo audio files (44.1 kHz, stereo .WAV format). Recordings can be stored or played back on a computer or transferred to CDs or other media. The piano’s built-in full playback function permits use of such features as pause, fast-forward, rewind and A-B segment repeat.

• Software available on the market may be required for producing CDs.

MIDI Recorder

This function enables players to record their own performances freely in the CELVIANO Grand Hybrid’s memory. It helps users improve their playing skills by reviewing their own performances objectively afterwards. This full playback function permits use of such features as pause, fast-forward, rewind and A-B segment repeat during playback.

Music Library

CELVIANO Grand Hybrid includes 60 piano pieces in its “Music Library”. The scores for these pieces are included and CELVIANO Grand Hybrid’s features are ideal for learning. Left and Right hand parts can be practiced separately. Tempo can be changed and an A-B segment repeat allows you to practice a section of the piece. Each piece has a selected preset tone but players can enjoy their own choice from the Berlin Grand, Hamburg Grand and Vienna Grand tones.

• Some musical scores are not published due to copyright issues.

Duet Mode

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.

Layer and Split

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

Auto Power Off

To conserve energy, CELVIANO Grand Hybrid will Automatically Power Off when the instrument has not been played for 4 hours.

Intuitive control of CELVIANO Grand Hybrid is possible through a simple, considerately designed control panel. The Berlin Grand, Hamburg Grand and Vienna Grand are easily accessed with dedicated buttons for each piano tone.

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 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.)

Casio 80s Keyboard Simulator

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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