Yamaha MK-100
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Yamaha MK-100
A rare and unique pre-FM Portasound from 1983.

Yamaha MK-100 (1983) - MK = Music Keyboard


The MK-100 shares a sound chip with the PSS-260 and 450, but with the novel feature of the rotating Multi-Menu and a few other more sophisticated functions. Its 12 preset tones are modifiable via the envelope and waveform synthesizer functions in the Multi-Menu, and a second layer can also be added, giving a huge range of possible variations.

Unfortunately the onboard stereo chorus wasn't working at the time of recording; I substituted my favourite 80s chorus pedal, the Yamaha SDS CH-10MII, which always sounds good on keys.

This track is on the Once album...

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This video showcases the features of the rotating Multi-Menu, which allows you to modify the 12 preset tones via the envelope and waveform synthesizer functions, or add a second layer. You can also change the accompaniment and record a performance including a melody line. All sounds recorded directly from the MK-100 with no extra processing.

In solo mode the MK-100 has 7 note polyphony, although this reduces as you add layers or play in duo or trio mode over the auto accompaniment.


In this one, I used only the preset tones (the "orchestra") without any additional modifications from the Multi-Menu. These presets are the same as on the PSS-450, released a couple of years later. All parts of the track were recorded straight to a Tascam Porta05 4-track cassette recorder. A touch of reverb was added during mixdown.

Hear the album


A close-up of buttons and sliders on a Yamaha MK-100 keyboard