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GX-1 - Image 1

GX-1

KeyboardAnalogPolyphonic

Back in 1973, this beast redefined what a stage keyboard could do, blending organ-style grandeur with true analog synthesis—Yamaha's bold leap into polyphonic sound that left jaws on the floor for rock icons like Keith Emerson and Stevie Wonder.

Picture a triple-tiered setup with two 61-key velocity-sensitive upper and lower manuals, a 37-key pressure-sensitive solo keyboard, and a 25-note pedalboard, all perched on chromed pedestals totaling around 387kg. Eight polyphonic voices (up to 18 notes across keyboards) draw from dual analog VCOs per voice, shaped by a 2-pole VCF, ADSR envelope, and LFO, with group-controlled voltage for evolving, organic tones you edit via dedicated Tone Modules and a visual guide board. Controls hide in drawers—drawbars, ribbon controller, pitch bend, sustain, resonance, reverb levers, plus swell pedals and a knee lever—while valve-powered TX-II cabinets (up to four, 141kg each) deliver cathedral-like dispersion through multi-driver arrays.

Players still geek out over its lush, expressive depth that paved the way for the CS-80, though its sheer size and travel fragility spark tales of heroic roadie feats; a few note the fussy tuning needs from all those discrete boards, but that's the charm of vintage analog heaven.

Released

1975

Status

Discontinued

Synthesizer
Format
Keyboard
Type
Subtractive
Internal Battery
No
Voice
A/D
Analog
Polyphony
Polyphonic
Oscillators
2
Oscillator Type
VCO (Voltage Controlled)
Voices
8
Filter
Lowpass, Highpass, Bandpass
Envelopes
2
LFO
1
Effects
Analog Rhythm
Expression
Aftertouch
Polyphonic
Velocity
Yes
MPE
No
Additional
-
Software
-
I/O
Audio In
-
Audio Out
5-channel (8-pin Leslie-style)
Headphone
-
MIDI
-
MIDI Type
-
Ports
-
Wi-Fi
No
Workflow
Arpeggiator
-
Sequencer
-
Mod Matrix
-
Memory
None
Measurements
Dimensions
1600 x 800 x 1140 mm
Weight
300 kg + 87 kg pedalboard
Last updated Mar 25, 2026