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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 input
- stereo out
- expression pedal input control for filter cutoff
- footswitch input program up
- footswitch input sustain
- footswitch input EG release
- footswitch input glide control

system generates 8 voices polyphonysplit on 4 boards.
A voice is composed by 2 DCO oscillators + 1 white-pink noise generator.
Some special DCO functions:
- second DCO can be hard-synched to first one
- 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

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


effet VST PLUGIN / SAMPLED VERSION there are some free and commercial samples set:

  name price link demo
vintagelegends UVI Vintage Legends commercial effet demo
synthex VST ZOOTOOK FREE VST effet N/A



cat on synthex

demo 1 - laser harp classic
demo 2 - filter sweeps
demo 3- modulation strings
demo 4- Small town synthex with SCI drumtraks
demo 5- trio jam with Roland TB-303 and TR-909
demo 6- Lucky square with delay Dynacord PDD-14
demo 7- mix demo by S.Codazzi
demo 8- mix demo by R.Gallio

cloud sound Soundcloud 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.







elka synthex free schematics

Elka Synthex schematics



german scan




german scan



synthex data sheet





music messe


scanning magazine


jarre synthex


scan germany

laser harp
discover the LASER HARP





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. A true sonic cult."

The elka synthex board is for review, tips and questions. Please write only in english.



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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