The Yamaha SY-55 was released a year after their TG550 Tone Generator and apart from the attached keyboard, these two share a lot of similarities. The SY-55 is a digital workstation that is based on samples-playback and also one of the first rompler workstations by Yamaha to ditch the DX7 FM synthesis.

It is a 2nd generation 16-bit AWM2 system that makes use of wave data digitally at 32kHz or 48 kHz. The SY-55 also has 24-bit internal signal processing capabilities along with high-res 22-bit digital-to-analog converters. Thanks to its digital filter system, it is possible to shape sound in real-time and it comes with two megabits of sampled waveform ROM for a choice of 74 individual waveforms. With this synth, you get two modes of operation. The first, Voice, allows you to select and play a single sound. The second, Multi, is used for multitimbral setups that you use with the sequencer. In addition, it has a versatile 1,2, or 4-element voice architecture and complex envelope generators to provide users with extensive sample layering capabilities.

In terms of design, the SY-55 features a 61 key keyboard with both velocity and after-touch for expressive control. On the left of the front panel, you'll find the self-centering pitch bend wheel along with the modulation wheel. Above these are the DATA and WAVEFORM card slots while in the middle you'll find the master volume, sequencer keys and indicator, as well as internal, card, and preset keys. The MULTI key and indicator, SEQ key and indicator, as well as 16-character x 2-line backlit LCD panel are also on the front panel. The rear panel consists of the power switch, MIDI In, Out, and Thru connectors, click volume control, Output R, and L/Mono jacks, and phones jack. Here you will also find all the jacks for optional peripherals, such as a Yamaha breath controller, foot switch and foot controller.

Compared to the 16 track SY-77 sequencer, the SY-55 sequencer only has eight tracks but can hold eight songs instead of just one. It has a memory capacity of 8,000 notes, which is half of what the SY-77 offers. The SY-55 also provides 34 fully editable effects, ranging from reverbs and delay to digital distortion and more.