The Yamaha DX100 is an FM synthesizer released by Yamaha in 1986.^[4][5][6] It offers four operators for each of its eight voices, and has eight algorithms (compared to the DX7's six operators for each of its sixteen voices, and thirty-two algorithms). It has only 49 mini-keys, and no arpeggiator or effects, but is still useful, known in particular for its bass patch #1. It features up to 192 presets, seriously improving the DX7's limited preset capabilities. It can also store 24 user-programmable sounds in RAM. It lacks cartridge support, but voice patches can be saved to and loaded from an external cassette recorder.

It was the cheapest user-programmable FM synthesiser made in the 1980s, leading to its popularity even amongst professional musicians in the 80s and 90s. It's essentially a cut down version of the DX21 and DX27, using the same FM chip, the YM2164.

• Yamaha DX1
• Yamaha DX5
• Yamaha DX7
• Yamaha DX9
• Yamaha DX11
• Yamaha DX21
• Yamaha DX27 / 27S