Oberheim OB-X

via this auction

"BONUS ITEMS:
1. Calzone case is included.
2. Two factory tape cassettes – both sides contain factory patches, plus patches that I created
3. The original owner's manual, First Edition July 1979
4. A copy of the service manual, Second Edition Feb 1980 Second Printing June 1980
5. OBX pin – the actual size is 2cm X 2cm, and is best viewed small.

HISTORY OF THE OBX ACCORDING TO VARIOUS INTERNET SITES

The OBX was the first fully programmable polyphonic synth built by Tom Oberheim. This machine was only in production for about 12-months, from 1979 until late 1980. It is estimated that less than 1000 total units were produced in 4, 6, and 8 voice configurations. The 4 voice originally retailed for $4595.

It's the direct successor to the famous SEM based units. The secret of the OBX is that it still has the old discrete 12db SEM-filters (instead of 24db filters). Each voice card in the OBX is in essence an expanded SEM controlled by a common user interface. All later units such as OBXa, OB8 and Matrix as well as many competing products made the use of the more sterile Curtis filter chips. The OBX has a warmer sound than the OBXa and OB8 (which are both CEM based). Tom Oberheim also said that the OB8 is too perfect, lacking the earlier models' grit, and that he prefers the sound of the earlier Oberheims (the SEM and OBX) to the later models. In addition, the Polymod (Xmod, Crossmod) feature never came back on the later machines.

WHAT USERS SAY ABOUT THE SOUND OF THE OBX (WHY YOU WANT IT!)
The OBX blows away every single virtual analog or modern digital synth ever made. It sounds huge, wonderful, and very much alive. It has so much more life, character, and sonic power than any of the modern synths I've owned or heard, I swear it's got a life of its own! I can just mess with it for hours, totally captivated by the sounds it can make. Comparing the X with the Xa in 12db mode the X sounds less transitory and closed in with better bottom end warmth and sweeter resonance. Don’t expect an Xa in 12db mode to give you an OBX. Knocking the Xa into 24db mode gives that famous Xa Punch no doubt helped by its faster EG’s but still gives that "Curtis 3320 VCF " pinched effect despite OB doing an excellent job of making the best use to date of a mediocre chip. OBXa is NOT smooth, it’s agressive and ballsy. The OBX sounds like true Oberheim, not like a "Jump"ed up Prophet 5. For big lush pads and Sweeps IMO the OBX trashes the OB-Xa every time. OBX is one of the smoothest, warmest, biggest sounding synths out there. The sound of the OBX is absolutely superb. It's crystal clear, full and very open. The sound of the filters is second to none - no other programmable polyphonic analog synth will give you such rich sweeps. 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 OBX is THE pad-monster."

inside an OB-X