Oberheim OB-X

My OB-X is a rev. 2, mounted (for the moment) with 6 voice boards. One big synth, with knobs and a lot of space between. The opposite of MFB synths...It's also a heavy instrument, and doesn't like to be moved around. When i bought it there is 4 years, the preset where all erased. The manual (from 1979) is informative. But i don't need it. It's so easy to use, in 3 minutes you know where to find every function of the board.

The OB-X is allways a little bit the bad duck of the Oberheim Familly. It doesn't have the possibilities of the younger brother (OB-8), lacks the multimode filter from the father (SEM), and is quite rare to find on the synth market. It's a very basic synth, with 2 VCOs, 1 LFO (modulation with both VCO separatly, Filter, etc...), 2 envelopes, and a wonderfull 12dB/Oct lowpass filter. So allmost the same possibilities like on the OB-Xa, but there is no Split, Dual Function for the keyboard, and no 24 dB/Oct filter option. There is also only 32 memories, instead of the 120 memories on the OB-Xa. Of course, no mid, no graphic display, no USB, etc...But a stereo output, and the ability to place the voices on the left or rigt side of the space ! A very special stereo effect.

There is no effect board, but you DON'T NEED one. The sound is so huge. You can still add a little reverb or delay for fun. But no chorus needed like on a Roland Juno.

GV/Gate In and Out to control the Voice Card 1. Very cool in use with an analog sequencer...

I planned to mount a Encore Midi Kit. And fill up the inner space with 2 Voice Boards. So i will have a 8 Voice OB-X with midi and 120 memories.

This is really the strength of this synth. Don't expect the wildest FX...There are other synths for this use. Don't expect the same deepness in programmation like a Matrix 12 or a Jupiter 6. It's a simple polyphonic synthesizer.

BUT, with a big, fat, organic, deep sound. The enveloppes are perhaps not the fastest (it's not Roland Jupiter 4...), but you can easily achieve a correct bass sound with it. It makes amazing pads. From very open, and very clear sounding (allmost glassy) strings, to obscure and 70's deep pads. Also brass sounds, drones are a breeze for the OB-X. Like said before, you don't need any external chorus or phaser to fatten up the sound. It's ultra fat from the beginning...absolutely crazy ! From the osciliators to the filters. The discrete electronic, derived from the SEM is responsable for this sound.

This is the point where the OB-X is really not shining...It's a 30 years old instrument, the electronic is getting very old. And to find an OB-X in perfect conditions is allmost impossible. And you find one, you will have to change the trim-pots and a lot of tantal capacitors to achieve a full-functionnal OB-X. Mine has some issues with the Auto-Tune Function that is bugging 66% of the time. I'm lucky, my OB-X stays in tune for hours and hours. So i don't need the auto-tune. But i can't say that it's in mint conditions...

Seems that Tom Oberheim is back in the business. But i don't think he will make a support for this vintage board...The chance is that the OB-X is allmost made only with discrete components that you can find in every electronic shop. So it's quite easy to find the parts to fix it up. Only the envelopes are made with Curtis 3310 chips. But it's possible to find them on the net.

Yes...it's a little bit like the Roland Juno 60. Perhaps not the most versatile board on earth, quite limited in therm of sonic possibilities, but with an super easy user interface, and a huge, deep and warm sound.

If the instrument would really get broken in the Motherboard, i would pick up the individual voice boards and make SEM Module with it...it's worth only for the sound !

So please Tom Oberheim, if you bring some new gear on the music market, discrete electronic like in the OB-X, and with the same Oberheim Vibe like in the 70's !

Thanks a lot for this wonderful instrument.

The presets are long gone but the pads i have made are impressive and easy to create. Manual is cool to follow.

Mine is 8 voice though 4 and 6 voice models are available too.No midi but i dont care-sound is all to me!
Keys can be stiffer than modern synths.

Great for pads low fi wobbling boards of canada style sounds lush string pads-i like to detune osc 2 slightly to give depth and richness. Great filter sem not curtis chips so real analogue.I LOVE THE SOUND YOU GET FROM THIS STYLISH BEAST.Had a pro 5 rev 3.2 and kept this as opposed to the pro5 which surprised me-rev 2 perhaps different story but ive not heard one....yet

No reliability problems with mine in 6 months-fingers crossed-gigs?-no i think more of a studio set up instead.Others have said problems so i give it a 9.

doesnt exist as far as i know -now gibson run the name oberheim.

i may never find an 8 voice this good ever if stolen
i love the sound and look
pro 5 rev 2 is the next thing i want but i fear reliability
ill give this a 10 overall as ive played pro 5 rev 3 roland jx 10 jx8p and 3p juno 106,60 korg polysix and it blows them away

The OB-X is a big and relatively heavy instrument - and a great looking one! There are 21 knobs, 39 buttons, 3 switches and two Oberheim-style levers. There are no double functions - every parameter has its own control. So the OB-X is very easy to use and you got a great overall view.

The OB-X was released in 1979 and was the first programmable polyphone synth from Oberheim. It's the direct successor to the famous SEM-based four/eight voice. The main point is, that the OB-X has the same discrete filter design as the SEM-modules - there are no curtis filter ICs as the followers OBXa and OB-8 got. But the filter is not as flexible as the SEM-one (which were multi mode) - it has a fix 12dB lowpass setting. When you open the belt, you will see boards with tons of electronics. Every voice has got it's own circuit board - they can be removed separately. A maximum of eight voice boards can be installed - mine has got six. For stereo use, every board's output is assigned to a pan pot. Every voice board has two VCOs with saw and pulse. The VCOs can be synced and crossmodulated (you won't find crossmodulation in the followers OBXa and OB-8) - so there can be generated strange and metallic waves. There's a great polyphonic portamento section, an autotune function and a hold button (which can be used as a chord memory as I found out!). Then we got the described filter section and two ADSRs for filter and amp. The sections can be modulated with the Oberheim-typical modulation matrix. An LFO with quare, triangle and S/H can modulate the LFO pitch, the filter cutoff and the pulse width (separate for VCO1 and 2). There are 32 memory locations to save your sounds. Of course you can edit programs any time - just push the edit button and turn the knobs as you like. There's a casette interface to load and save memory banks. On the backside you find some goodies: a CV/Gate interface to control voice 1 and a filter control jack, where I've connected an external potentiometer to modulate the filter cutoff without any stages - which sounds absolutely great. This direct and precise cutoff control you will never ever experience with a software synth. You can really navigate to a particular partial tone and hear it growing louder until you got it exactly! What I learned to appreciate furthermore are the Oberheim-typical levers. They allow you to bend the tones of the Oberheim like you bend a guitar string - the levers are very responsive. It's easy to bend up a note and modulate it at the same time. I admit freely: I'm not a fan of wheels - I like better the korg joystick. Unfortunately, the Oberheim-concept has been abandoned.

The sound of the OB-X is absolutely superb. It's cristal clear, full and very open. There's no noise at all - very rare amongst analog synths - which speaks a word of its building quality (in 1979 only professionals could afford an OB-X). The sound of the filters is second to none - no other programmable polyphone analog synth will give you such rich sweeps (the Memorymoog of course has superb filters too, but they sound different because they are 24 db which is better for percussive sounds). The fact that every voice board's settings differ a bit from each other makes the sound very lively - a chord never sounds stiff. In short words: the OB-X is THE pad-montster. Be aware: it sounds totally different than the OBXa and the OB8. It can't do everything: it does not deliver the pecussive and punchy sounds for which the OBXa and OB8 are famous for. It sounds a lot more brute, less precice but a lot more interesting and lively (no "curtis coldness"). All this might be reasons why Hans Zimmer uses an OB-X in his Hollywood studios.

This is the weak point: the OB-X is a very delicate and unstable piece of gear - probably caused by the masses of plug connections and electronic devices. Mine had an LFO problem as I bougt it - I had to get it to a technician who almoust got grey hair solving the problem (he ended up doing A-B comparisons between mine at a "well" model). The whole story did cost me a lot of money (almoust 50% of the buying price!). Later on, four of the six voices did not react any more - which was a plug connection problem as I found out after many hours of measurement. The next problem were the leaver pots, which got unstable (probably the age) - I replaced them with wire-precision-pots. I ended up replacing all trim-pots of the voice cards with modern precision trim-pots. A further problem are the key contacts: they break all the time and you have to solder them. So be aware: when you're purchasing a used OB-X you have to be prepared to spend a lot of money and time the get the machine keep on working - but maybe you are more lucky than me...:-)

Maybe you have luck and meet Tom Oberheim himself somewhere... :-)

The OB-X is a great sounding monster - but very rare on the used market. There are not as many pieces around the globe because it was built only from 1979 to 1981. It has still the real SEM-filter sound and thanks to the x-modulation a lot of potential for experimental sounds (which is missing in OBXa and OB8). Nevertheless, I would recommend the OB-X only to real sound fetishists who are willing to fight with its techical instableness. It's your decision!