Yamaha YS100

Frequency Modulation Synthesizer (1988)

A cut-down version of FM digital synthesizer YS-200 lacking the built-in sequencer and keyboard aftertouch.

User manual Service manual The 4OP family page

Overview

OVERVIEW 61 keys, covering 5 octaves which supports velocity sensitivity / Split mode and Multi mode can be assigned. On the left wheels for pitch bend and modulation control are provided on the left side of the keys.
Simple LCD display and a built slot card for sound storage

RELATED MODELS:
- Yamaha TQ5 more or less the module version
- Yamaha YS200 same adds the sequencer and aftertouch

Terminal connectors:

- Midi Interface (19abc)

- main signal out stereo (22)

- pedal input for volume (20)
- pedal input for sustain (21)
- breath controller input like BC1 or BC2 (front)
- headphones (front)

Sound

OSCILLATORS HD63C03YP +SUB manages 8 voices polyphony- DAC ym3017
Main IC chip YM2414 features 4 OP + 8 combinations - unlike DX7 synthesis based on a 6 operators system with just pure sine wave and 32 combinations algorithms. Internal ROM contains a stored digital half sinewave on a lookup table that can be read in different way and speed, creating 7 harmonics sine waves variations with partials overtones and fundamentals fixed settings.

ALGORITHM YS100 features several OP signal paths combinations with frequency ratio or fixed frequency: the output is fed back to its input with 7 feedback levels, as general rule, high values feedback results in richer harmonic contents.

- carrier defines the amplitude and the spectral frequency

- modulator sets the sound timbre and the relative harmonic contents.

LFO 2 X delayed and re-triggerable modulators (shapes: saw tooth, square, triangle and sample & hold, frequency range from 0.007 Hz to 50 Hz).
LFO DESTINATIONS are :
- LFO1 to amplitude
- LFO2 to pitch