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GEM S2 / S3 Turbo 

Music Processor (1992)

Gem S2 Turbo

"An ambitious synthesizer-workstation project from the Italian society Galanti right after their successful keyboard WS-2, later in 2009 Gem declared bankruptcy"

 Main Data 

GEM s2

Company: GEM
Model: S2
Class: workstation 
Dates: 1992 
Keyboard: S Workstation has been released in 2 versions with same engine:
- S2: 61 velocity keys   (dimensions: 1055x116x350 mm / weight: 16 kg)
- S3: 76 velocity keys (dimension 1077 x 116 x 350 mm/ weight: 18,5 kg)

Display: neon 240 x 64 pixels
Synthesis: digital rompler
Polyphony: 32 voices
Multitimbric: 16 parts
Resolution: 16 bits
Sample Freq: 41,7 kHz
N. PCM: 209 waves
Oscillator: 2 PCM
Filter: LPF / HPF / BPF / BOOST
LFO: 3 modulators
Sequencer: 250.000 notes
Sync: Midi Clock
Midi: IN / OUT / THRU
CPU: 68302
DAC: AD1865N 

KEYBOARD main panel features a 240 x 64 pixels display, 86 buttons, a wheel, 7 sliders assignable to parameter or Midi CC# and 2 wheels for modulation and pitchbender.  

Controls: Aftertouch, Buttons, Faders, Pedal - Filter, Mod - Wheel, Modulation 1/8" Jacks, Pitch -Wheel, Sequencer, Pedal - Sustain, Tempo Knob, Velocity, Pedal - Volume

Back panel terminal connectors:
- double Midi interface
- main signal out
- 4 AUX analog outs 
- volume pedal input
- 2 pedalswitches assignable to: damper / expression / start-stop / patch change

NO factory reset procedure


Have some sounds or demo  want to share? CONTRIBUTE :) 

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 In details 


 TECH core is based on a CPU Motorola 68302 clocked at 16 MHz manages 32 voices polyphony - 18 bits resolution DAC model AD1865N.

 A S2/S3 patch is composed by 1 or 2 PCM samples that can be combined in 3 modes:

1. PCM SO single

1 digital oscillator PCM per voice, simple sample for 1 voice polyphony. Very simple to start a new sound.

2. PCM dual Osc

2 layered oscillators but no interaction between waves but a simple  volume balancing.

3. PCM  DC XF dual

The GEM system crossfades 2 times  the same PCM for a better wave rendering, but this process takes twice voices polyphony.

Gem s2 sound path
Crea fantastici siti web!

The "S" wavetable 

209 PCM

The 6mb ROM wavetable is organized into 16 instrument categories (piano, reed, string, effects, chromatic, pipe, ensemble, ethnic, organ, synth lead, brass, percussive, guitar, synt pad, bass and drumkit).

41,7 kHz rate

There are 3 ROMS for the whole wavetable, which cannot be expanded but by loading external samples if turbo kit is mounted (check "sample import below)

16 bits resolution

The S2/S3 features some waveforms inspired from classic analog synthesizers e.g Elka Synthex, Roland Jupiter 8.

PCM wavetable

Sample import upgrade (turbokit)

An optional board was available which add some new functions, improvement and a sample import function (move over on pics for details)

sample import

Sample import

This function available only if turbo option is fitted which adds 3 import modes:

- floppy MS- DOS & Atari ST format supports .wav .aif - Avalon
- standard SDS Midi dump.
- floppy disk Akai S1000 format

Turbo kit

The Turbokit

 TURBOKIT is an expansion board with some new features and enhancements including the sample translator which is a tool for samples import. The installation is not easy and requires some technical knowledge. 

Note that rackmount S2r is TURBO standard factory.

 S2 / S3 Performance

 GEM MIOS is a multi-thread Kernel which manages 16 parts with individual settings:

- Midi channel assign
- dynamic zone split 
- pitch tune 
- stereo panning 
- microtonal control 10 scale presets  + 4 users- CC# are supported but MIOS cannot handle extended Midi Sysex.  Full control change LIST.

EFFECT S2/S3 handles 2 main engines:

- DSP 1 is dedicated to reverb and echoes
- DSP 2 is mainnly focuses to modulation e.g chorus, flanger, phaser and organ rotary speaker.

Full effects LIST





2 independent resonant multimode filters, each provides a -12 dB per octave slope and combined they operate as a single 4-poles filter:

- lowpass
- highpass
- bandpass
- parametric boost / cut



up to 2 interchangeable and Midi syncable modulators (shapes: sinewave, triangle, sawtooth, square, random and sample & hold) and 4 destinations:

- LFO to amplitude
- LFO to pitch
- LFO to filter 1 / filter 2 



2  EGs

- EG 1 amplitude: 10 segments when note engaged + 10 others when key is released
- EG 2 filter: same as EG1

TIP: It is possible to select also a 1 / 3 /6 macro segments all edited graphically using the data encoder.



Internal 16 tracks Midi SMF compliant (with import functions).
 Some standard edit functions such as copy, insert, delete, quantisizer and microscope edit.



- 250.000 notes
- 16 songs 

512 Kb sample RAM up to 2Mb using SRAM UPD431000

Data can be saved only to disk HD 3.5” formatted at special 1,62 Mb file system

BATTERY famous internal Ni-cad 3.6V battery leakage see "maintenance"


Maintenance and issues

gem s2 s3 battery

Battery leaking

Infamous internal Ni-cad 3.6V battery leakage.To replace it unsolder the battery, clean the board from the acid-salt and eventually replace it with a fresh one.

Note: a new battery costs about 3-4€ there is nothing special about it. You can even not install it if you don't have the extra sample ram, you will just get rid of the day/date for files. You can live without it.


Encoder fail

Jumping encoder needs cleaning with q-tips and an appropriate liquid solution, or just find an equivalent rotary device.

Gem S2 USB

Disk drive failure

DISK DRIVE may fail, try a good cleaning first. It is possible to install an USB emulator, I tried and worked, but cannot find the right geometry as it won't fit into S2r tiny slot! :) will think about that someday.

Our Verdict 

" Great filtered sweep pads, deep droning choirs, but obsolete for acoustic emulation. Sadly S2 and S23 are ruined by stupid technical lacks like Midi exclusives and storage.
But give it a try! now bargain price on second hand market. A true old .. gem!  "





Quality / 



-  storage
- no extended exclusives system
-  memory system


- some PCM
- great masterkeyboard

Are you a S2 / S3 fan? how do you use it? You do not agree with our review?  Let us know in the comment field just below 




S2 / S3 advert, scan, review