Korg X-911

“Korg X-911 guitar synthesizer everything works!

This is a 1980’s attempt at something we do much better today with a pedal, but it’s cool for it’s quirky interface and it has the heart of a MS-20 filter and voicing in it. Plus it is now controllable with the Arturia Keystep 37!

It takes an audio input and processes it to generate a pitch voltage and envelope… using it to trigger two separate voicing sections which share the same oscillator. One is called Instrument and the other Synthe… you basically add the presets up on each side and blend them with the Balance slider. Each one has an adjustable filter setting or attack/release with the mini knob. You even get portamento which you can footswitch along with a hold function and interval jump.

It is only OK as a guitar synthesizer (it does work, I used a compressor in front) but it ROCKS as a mono keyboard filter unit or for running drum machines through… vocals can work but are iffy… don’t expect vocoding. I used a Fender Rhodes which worked well, so a Rhodes patch should too. Note it also puts out this voltage and trigger, but it’s Korg standard. It is monophonic, so the ‘voices’ are really just filtering the same oscillator in different ways. It is only good for tracking along about two or three octaves at most through the audio input, but tracks well if CV in is used over several octaves.

It does have CV and trigger in and out but they’re a weird Korg Hz/V standard, not normal 5V linear. So this will work with a Kork MS20 as an expander, or Korg Sigma/Delta/Lambda or even the PS3xxx series if you have a super studio! But not anything else.


If you have an Arturia Keystep 37 (not sure about any other Keystep controllers but I ran mine with a 37) you can use it as a controller and arpeggiate or sequence in addition to just playing from it, or even control the filter or LFO with a couple of cables! This is a blast and the killer app for this little gem. If you have the Keystep now this is a great add… if not and you get this at least try one with it.” Click here to visit listing on eBay

Korg X-911

“This is a Korg X-911 Guitar Synthesizer I bought from Soundgas.com last year.
As everything that you can get from that shop the device is in fantastic shape, its from 1979, so minor
signs of usage as to be expected from a vintage instrument but in 100% working order,
nothing scratches and sounds great! Includes the service warranty document shown in the picture.
Comes with a voltage transformer as its a Japanese version. ” Click here to visit listing on eBay

Korg X-911 Project Machine

“Tested and works somewhat, but needs to be repaired for full functionality. I sequenced it with a Keystep, and while I could get clear sound out of it, and the filter, octave, volume and different synth sounds worked, some of the functions did not seem to respond correctly or at all (i.e. some of the synth sounds did not respond to the envelope/tone controls). Also, I did not test the guitar input functionality, and the slider is janky (but works). I would put it at about “70 percent working.”

Because of this, this unit is being sold AS-IS with the understanding that it will need to be repaired.

Strange and powerful unit. Can be used as a guitar pedal, but can also be sequenced/controlled with CV/gate. So, essentially a desktop synth, even though it was marketed as a guitar pedal. Please note that it uses KORG’s CV standard, which is different than the Eurorack standard.

The filter in this baby is rumored to be the same as the one in the MS-20. So, here’s your chance to get that sound at half the price!

This is the 117V US version, so you will not need a voltage converter for the power.” Click here to visit listing on eBay

Korg X-911 Project Machine

“For sale is a Korg X-911 Guitar Synthesizer.

This is sold for parts only/as-is. The portamento section does not work, when the knob is turned nothing happens to the sound. So it will need some sort of service/repair to get it fully functional. May need some additional calibration.

The other knobs and buttons affect the sound as they should. Output knob is a little scratchy when turned. Body has some scuffs and marks on it. From a smoke-free home. 120V AC Version. Picture is of actual item for sale. ” Click here to visit listing on eBay

Korg X-911

“Korg X 911 And Kong Ms04 Pedal. Unique Analog Guitar Synth Like Ms20. Crazy vintage guitar synth coupled with the MS04 pedal allows you to make crazy squelchy acidy LFO analog sounds with your guitar.

Pedal takes 2 9 volt battery’s ” Click here to visit listing on eBay

Korg X-911

“Korg X-911 Guitar Synthesizer Analog VCO VCF Distortion Wah. In very good condition for its age, Condition is “Seller refurbished”. There is some surface ware, no structural damage, a couple of small screws missing from the front and back panels, has been tried tested and is fully functional, I don’t have the time, to explore the full depth of its true potential, as I have to many family commitments, you will find quite a few videos on YouTube, demonstrating this nice piece of electronic retro, ” Click here to search for synths on eBay

Korg X911

“Works 10 of 10
Overhauled before shipping for long life and to keep original sounds.
Change all electrolytic capacitors and voltage regulators, short life Operational Amplifiers and logis ICs with new ones.
Knobs, switches and jacks cleaning.” Click here to search for synths on eBay

Korg X911 Project Machine


Korg X-911

“A guitar synthesizer released by Korg in the late 1970s.
The waveform and other tones can be selected with the button, and the envelope is attached, and the synthesizer parameters are firmly mounted.
Status There was no problem with both input and output. Various knobs are also responding.”
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Korg X-911

“I’m selling a fully tested and working used Korg X-911 Vintage Analog Guitar Synthesizer. It’s in great condition and has been played and tested recently. The pictures show how nice a condition it’s in.”
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Korg X-911

“It is a so-called guitar synthesizer. Roland is generally famous for guitar and synthesizer, but KORG also announced a compact model with less malfunction. Not limited to guitar, any instrument can be used as a source as long as it is a musical instrument that produces sound with a single note. You can mix several kinds of presets, or you can control the harmonic overtones like an organ’s drawbar to obtain a sound that can not be obtained with an effector.
Hold and portamento are also possible, envelope is also attached properly It can be said that it is a real synthesizer.
Operation confirmed.” Click here to search for synths on eBay

Korg X-911

“Up for sale is rare Korg X-911 vintage analog guitar synthesizer.

The unit appears to be working reasonably well, I noticed the TUBA sound seems to be only producing small noise somehow, but otherwise all other sounds working and sounding fine as well as all the knobs and switches working as they should. There may be a slight bad contacts on the BALANCE slider, which could probably also do with some servicing/adjustment. All the LED lights above each buttons lighting up correctly when pressed.

Cosmetically the unit is in very nice condition as you can see. There are some signs of wear and minor marks here and there, but nothing major. I’m including plenty of photos so you can see exactly how it looks.

Comes with the Original Plastic Overlay as shown.
Power cable included.”
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Korg X-911

“Olivia’s Vintage would like to present this 1980’s Korg X-911 analog Guitar Synthesizer. It’s triggered by any instrument using regular input and output jacks. It’s a very unique synthesizer and 100% working. It’s in great shape with only some minor cosmetic wear.” Click here to search for synths on eBay

Korg X-911 Project Machine

“Partially working with faults!

Instrument side:
Elec Bass LED always on (doesn’t Cancel) No sound either from this preset.
Tuba never switches on, so no response from this one either.
the other 4 work as intended, including trim pots.

Synthe side:
LEDs will light & cancel, but none are sounding.

I have a feeling this will centre around the filter chip rather than the buttons. Similar to the common fault in the Korg Delta. The parts are still available.

The left hand side of the panel is fully working, input, portamento/ interval/ tune/ octave all 100% on the 4 working voices. Still great fun to be had with this alone! Glitchy, Prog-type fun & Octave effects a-plenty!

Synthe filter knob not working, again pretty sure this is related to the synthe side. Possibly these tones go through the filter chip & the instrument side is filtered by resistors etc, as you have no control over those.”
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