Oberheim OB-Xk

Oberheim OB-Xk Image

The Oberheim OB-Xk is a MIDI keyboard controller from the mid-eighties. Originally designed to control the Matrix and Xpander modules, it uses MIDI and works fine as a controller for any MIDI gear. It's got 61 keys that respond to velocity and aftertouch, two OB-style Pitch/Mod controllers, and one assignable continuous control slider. From the front panel you can directly access the first 100 single patches and/or 100 multi patches of your MIDI module. Any additional patches must be selected by another MIDI controller.

Other features include the ability to transpose up or down by up to 2 octaves or by half steps. The keyboard can be split into 3 zones. There are basic Hold and Chord memory functions and an Arpeggiator section with pretty decent features (it can use internal or external clock). The OB-Xk can also send a sequencer Song Select, Start and Stop commands. It's built with Oberheim's classic & vintage look: solid black metal case with wood end-cheeks. Definitely a unique controller to have around, although severely limited by today's standards.

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18 Visitor comments
September 29, 2010 @ 6:52 pm
check this link out - this is the only one ever made -
September 29, 2010 @ 6:46 pm
The orginal power supply was not good (and why they were use is a different story) I actually put a real power supply in the proto-type, one with a AC cord.
Find a 9V at 2A wall-wart (1A is probably ok - but find at least a 2A. Do not use a 12V supply, it will work, but will create too much heat inside the XK. I have schematics, although I can't remember if I have the final production version, and owners manual (although it probably is not good because I wrote it, andof course I never used it)
An technican should have no problem fixing the power supply without a schematic - it's only two wires.
For fun - if you have an eXpander or access to one - plug the XK into it, hold down '5' '6' on the XK and power up.
I look for an early production one on ebay ever now and then - I'm sure the proto-type is pretty hosed (it barely worked to begin with)
all the best
September 22, 2010 @ 3:32 pm
Hello Craig!

I recently found one on Ebay for $75...mine was "lifted" back in the mid-90's.

This keyboard had the best velocity-sensitivity of any keyboard I've used.

I haven't fired up the one I just picked up as I don't have a power supply (I was told by the seller...a reputable guy...that it works but that the previous owner had removed the standard "center pin" connection for a "two prong" connection).

I'm going bring it over to a keyboard shop though I'm looking for the user and repair manual. (...like an idiot, I pitched my copy of the user manual...I could kick myself for that!)

Really a great controller!
August 5, 2010 @ 4:16 pm
Limited in a few areas but far superior in most other areas. Superior in the ability to control multiple synths/modules within the three Zones makes this a great studio and live controller. Most modern controllers lack the ability to do splits/layers/zones and will only trigger thing at a time, not the Xk! The Xk controls VSTi very well too, again control up to three VSTi on one controller is great! The aftertouch and velocity feel is very good. The arpeggiator in this is wonderful and has nice groove & feel to it, I have mine sync’ed to midi with a 96ppq converter box. The Oberheim style ‘flippers’ take a little getting use to but just gives you one more way to control band/mod. Built like a tank and not a cheap piece of plastic like all modern controllers.
August 5, 2010 @ 12:04 pm
Nice to see the comments.

I too, am starting to be limited now that 25 years have passed since I designed the XK. I sure wish the proto-type XK I have in my attic still worked.

There actually were (2) prototypes - the 1st one looks a lot different that the 2nd. The 2nd looks like the production version. I do have the 1st proto, and probably should take a photo. The 1st proto was a quicky for a NAMM show, and not too many features actually worked - but hey it was just for show & tell.
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Rated 3.4 (93 Votes)

  • Check Price
  • The link above will take you to an eBay search for this synth to see active listings. If you don't find it there, try looking in our forum marketplace or post a wanted classified.
  • Specifications
  • Polyphony - n/a
  • Oscillators - n/a
  • Effects - n/a
  • Filter - n/a
  • Arpeg/Seq - Arpeggiator with internal/external clock sources
  • Keyboard - 61 keys (velocity, after-touch)
  • Memory - 100 single patches, 100 multi patches, 3 zones
  • Control - MIDI Out (1 channel at a time)
  • Date Produced - 1986
  • Resources & Credits
  • Images from Synth Site

    Thanks to Scott Marcotte for providing information.

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