Casio MT-30 (1980)

A compact 49-key polyphonic home keyboard with fixed presets and onboard recorder, among Casio’s earliest midsize instruments.

Overview

The Casio MT-30 is a polyphonic midsize keyboard released in 1980, marking one of Casio's first entries into the home keyboard market. It features 49 mini keys with no touch sensitivity or aftertouch, and offers 22 preset voices ranging from electric piano and strings to brass and novelty fuzz tones. Despite its limited synthesis capabilities, it includes a built-in recorder and on-board learning system. The MT-30 lacks rhythm, accompaniment, and MIDI, but provides basic controls via white keyboard keys and a mode switch, including vibrato and sustain toggles. It was succeeded by the nearly identical MT-31, which mirrored the internal layout—most notably moving the speaker to the left side.

Specifications

Number of keys49
Key sizeMini keys (synth/organ style)
Touch sensitivityno
Aftertouchno
Polyphony8
Number of voices/presets22 presets preferred over pianoandsynth.com
Preset Sound listelectric piano, banjo, guitar, harpsichord, xylophone, celesta, glockenspiel, organ, accordion, pipe organ, oriental pipe, brass, cello, synthe fuzz, violin, trumpet, funny fuzz, st. ensemble, clarinet, flute, recorder, folk flute
Rhythmno
Accompanimentno
Sound generationtimbres based on 2 mixed stair waveform tones with different digital envelopes those are differently low pass filtered through capacitors.
Piano soundsyes
Real world soundsyes
Sounds editableno
Recorder/Sequenceryes
Tutorials/on-board learning systemyes
MIDIno
USBno
Tablet connectivityno
PowerAC Power: yes, Batteries: yes [sources disagree]
Speakersyes
Audio Outyes
Audio Inno
Audio Jacksjacks for AC-adapter, headphone and cinch sound output
Built-in speaker descriptionbuilt-in speaker (with a slightly unpleasant midrange resonance)
Sustain Pedalno
Soft Pedalno
Expression Pedalno
Main chipsCPU= 'NEC D775G , E11046' (64 pins with strange zigzag layout) DAC hybrid= 'EXK SIOL0025C' (11 pin SIL) amp-IC= 'LA4137' (14 pin DIL)
Controlsselected by white keyboard keys + mode switch, useless 'tone memory' 4 step switch to assign 4 of the preset sounds for quick access, vibrato & sustain switch

Design

The MT-30 features a woodgrain version possibly labeled MT-30W and contains a heavy sheet metal frame that supports the keys, with slide switches and potentiometers securely screwed to the frame rather than just mounted on the PCB. The black keys have plain sides, unlike later Casio midsize models. Internally, the loudspeaker compartment is horizontally separated by a pressboard wall and damped with foam rubber mats. The main PCB is small, occupying only about one-third of the case. Sound is generated using two mixed stair waveform tones with digital envelopes and low-pass filtering via capacitors.

Context

The MT-30 was the first polyphonic midsize keyboard with multiple sounds produced by Casio, positioning it as an early innovator in the home keyboard space. It belongs to the MT family of instruments and was directly followed by the MT-31, which is nearly a mirror image—most visibly with the speaker relocated to the left side. Casio competed in a market increasingly shaped by Yamaha’s presence in electronic keyboards.

Reception & Use

The MT-30’s sounds are described as bright, though most presets are considered unconvincing imitations of acoustic instruments—except for flute-like tones, which fare better. A notable feature is its behavior during trills with sustain: each new note uses a separate sound channel, creating a phasing effect and volume buildup. However, the bass range tends to overpower high notes due to muffling filters in the sound design.

Collectibility & Maintenance

Opening the MT-30 risks damaging snap-in plastic tabs that secure the case, often resulting in cracked tabs or scratched rims. Modifications such as adding a polarity protection diode and correcting power jack polarity have been documented. Hidden expansion possibilities include adding switches for mild vibrato, faster vibrato, octave down, sustain, hold, and spread tone scale, as well as enabling 12 additional lower note keys.

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