website templates

"An ambitious synthesizer-workstation project from the Italian society GEM right after their successful keyboard WS-2, later replaced by Equinox"

 In details 

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. Internal floppy disk HD 3.5” formatted at special 1,62 Mb proprierary file system.  Controls: Aftertouch, Buttons, Faders, Pedal - Filter, Mod - Wheel, Modulation 1/8" Jacks, Pitch -Wheel, Sequencer, Pedal - Sustain, Tempo Knob, Velocity, Pedal - Volume.
->The related 76 keys is the GEM S3 which is technically the same and rackmount version is GEM S2R , also a scaled-down version SX2

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. Midi CC# are supported but MIOS cannot handle extended Midi Sysex.

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

gem s2 rear


SOUND main 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 digital oscillator PCM per voice, simple sample for 1 voice polyphony. Very simple to start a new sound.
- 2 PCM dual Osc 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.

WAVETABLE The 6mb ROM wavetable (3x ROMS 41,7 kHz rate 16 bits) 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)
->The S2/S3 features some waveforms inspired from classic analog synthesizers e.g Elka Synthex, Roland Jupiter 8.

Sample import upgrade an optional board TURBOKIT was available which add some new features, improvement and a sample import function.
The factory RAM is 512 Kb and ca be expanded up to 2Mb using obsolete SRAM UPD431000
The optional boards adds 3 import modes:
- floppy MS- DOS & Atari ST format supports .wav .aif - Avalon  
- standard SDS Midi dump.  
- floppy disk Akai S1000 format
->Note The installation is not easy and requires some technical knowledge; that rackmount S2r is TURBO standard factory.

Gem s2 sound path


FILTER 2 X independent resonant multimode digital  filters, each provides a -12 dB per octave slope and combined they operate as a single 4-poles filter:  lowpass , highpass, bandpass and parametric boost/cut.

LFO 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.

ENVELOPE 2 digital 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.

EFFECTS 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.

SEQUENCER Internal 16 tracks Midi SMF compliant with import functions, 250.000 notes + 16 songs
Some standard edit functions such as copy, insert, delete, quantisizer and microscope edit.

Gem s2 sound path

Maintenance and issues

gem s2 s3 battery

Battery leaking

Infamous internal Ni-cad 3.6V battery leakage.To replace it desolder it, clean the board from the acid and eventually replace it:  if you don't have the extra sample ram, you will just get rid of the day/date for files. We 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

Gem S2 specs

Company: GEM
Model: S2
Class: digital workstation
Dates: 1992
Country: Italy
Keyboard: 61 velocity keys polyphonic aftertouch
Price: actual street price 200€ UP

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 romper
Filter: LPF / HPF / BPF / BOOST
LFO: 3 modulators
Sequencer: 250.000 notes
Sync: Midi Clock
Midi: IN / OUT / THRU

CPU: 68302
DAC: AD1865N 

dimensions: 1055x116x350 mm
weight: 16 kg

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


GEM S2  Demo



GEM S2 / turbo GEM S2 / turbo
65 out of 100 based on 12 user ratings
200 to 300 from 1 sellers Sellers: