- FM synthesizer (4-op), 8 note polyphony, 8 part multitimbral
- Easy edit controls for basic editing operations and job mode (to make FM more acceptable for subtractive synthesizer users)
- Programmable effect processor (10 built-in effects: reverbs (hall, plate, reverse, gated), delays (mono and stereo) and distortion coupled with either delay or reverb. There is very limited control over the effects other than time (up to 10s on some reverbs, 300ms on delays) and wet/dry mix.)
- Velocity sensitive keyboard
- Breath controller input
- 100 internal preset voices, 100 internal user programmable voices, 100 voices on the card
- MIDI IN/OUT/THRU terminals

YAMAHA Manual service - Manual for YS-100 as well as for most of FM synths