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Elka Synthex



elka synthex

title synthex

audio demo trend price : 5000€
manual schematic demo video comments

Elka Synthex (1981)


Impressive analog polysynthesizer designed by Italian organ societies Elka & Orla.

Synthex reached the olympus of all-time cult machine polysynth.

synthesizer Elka

left board

info KEYBOARD (weight: 30 Kg) 61 keys, optional pair of legs.
The main panel features 36 knobs, 84 buttons, 6 levers and a joystick for pitch bending and modulation.

Back panel terminal connectors:
- tape interface
- sequencer sync IN
- stereo out
- expression pedal control filter cutoff
- footswitch input program up
- footswitch input sustain
- footswitch input EG release
- footswitch input glide control

8 voices polyphony based on subtractive synthesis split on 4 boards.
A voice is composed by 2 DCO oscillators + 1 white-pink noise generator.
Some DCO functions:
- DCO 2 can be hard-synched to DCO1
- digital ringmodulator with fixed value


edit OSCILLATORS DCO structure:

octave range 16' 8' 4' 2' 1' 16' 8' 4' 2' 1'
waveforms saw / pulse / square / triangle saw / pulse / square / triangle
detune yes yes
PWM yes yes
sub oscillator no no
mix volume yes yes


edit PERFORMANCE the multiplexed boards features some advanced playmodes:
- double mode: is a layer of 2 sound patches
- split: assign 2 pacthes on a different keyboard zones
- polyphonic portamento with glide option and variable speed rate
- stereo pan mode, voice boards are sequenced to left or right stereo field

is a multimode resonant model based on 8 Curtis CEM 3320 chips.
The VCF works in 3 different modes with possible polarity inversion option:
- lowpass at -24 dB slope
- bandpass at -12 or 6 dB slope
- highpass at -12 dB slope



lfo LFO there are 2 modulators with different characteristics:

waveforms triangle /saw/ ramp / square triangle
destination pitch / width / amplitude pitch / filter
joystick trigger no yes
depth yes yes (by joystick)
delay start yes no


adsr ENVELOPE there are 2 EG:
- EG1 VCF: 4 segments ASSR
- EG2 AMP: 4 segments ADSR
In addtion 2 extra functions for envelope control: hold and sustain

a 4 tracks recorder with real-time or step entry notes.
Each track transmits Midi signals, then whole sequence can be shifted in real-time for performance.
Recording function are limited to 5 buttons and 2 knobs:
- write
- beats
- delete
- loop mode
- ready & reset
- 2 knobs for gate EG value


seq spec

edit SYNC internal frequency or slave mode controlled by external +5V trigger pulses.

based on TDA1022 is a 3-modes analog chorus fixed rate and depth values.

memroy MEMORY
- 40 ROM presets
- 40 RAM user slots
- 128 events per track (512 total)
Sounds can be saved only to tape interface.

midi MIDI
second and third Synthex versions implement a basic Midi interface that manage only basic note ON-OFF data.

Production Series
according to Castelfidardo center there are 1850 machines produced:
- wave 1: 50 units (no Midi)
- wave 2: 800 units (external Midi box)
- wave 3: 1000 units (standard Midi)

repair synthex
MAINTENANCE synthex suffers from common issues:
- voice boards lifespan that is quite unpredictable, fortunately there are not so many custom IC onboard, Synthex is mainly build with common electrical parts on the shelf.
- maintenance requires patience and experience since there are a lot of circuits inside.
- be friendly with you trusted technician.


picture by Gallio

big elka synthex


cat on synthex



6 Laser Harp is used by Jarre. info about this controller HERE

7 -Drums Sequential DRUMTRAKS

8 -Delay by Dynacord Pdd14

9- acid line Roland Tb303 drums+ Roland Tr909 + Vocoder SCV350

cloud sound Soudcloud Synthex DEMO

beethoven cloud2 cloud1


Paul Wiffen & The Elka Synthex Synthex Demo Sounds Synthenoxe Part 1.0
Paul Wiffen Demo Sounds Synthenoxe Part 1.0

Elka SYNTHEX - My Sounds 1 - 20 Laser Harp sound by Elka Synthex ELKA Synthex & Roland CR-78
My Sounds 1 - 20 Laser Harp sound with Roland CR-78

italian synthesizer


CHECK OUT Synthex prototype page featuring different voiceboards design.


wiseman says:

"even synthex beast need rest and repairs"
DOWNLOAD free schematics HERE.

german scan



german scan



synthex data sheet




music messe


scanning magazine


jarre synthex

laser harp
discover the LASER HARP




UVI Vintage Legends features some SYNTHEX samples but also Yamaha CS-70-20-40, Chroma, Yamaha DX1, DK Synergy and K250. AUDIO DEMO



synthesizer Elka panel slider


-Massive polyphonic sound
- Sequencer


- technical care
- basic Midi
- High price


"The Elka Synthex is one of few analog polyphonic-structured synthesizer that boasts deep bass, rich strings and complex magical electronic sound"

The elka synthex board is for review, tips and questions. Please write only in english. Trading posts are allowed, but at your own risks!



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all snapshots*, sounds, texts copyright Polynominal.com / Eric Pochesci
* overhaul picture by Riccardo Gallio: thanks! also for some demos.

elka synthex 4.5 out of 5 based on 101 ratings. price €5000