Oberheim OB-SX For Sale. For years, we avoided buying this vintage analog polysynth. We wrote it off as a non-programmable preset synth that had nothing to offer serious synth programmers like us. Until we were offered one that was used on some famous recordings back in the 80s. We knew we had to buy it and restore it. It was a huge endeavor that ended up taking a way too much time and money, but once we finally heard it, we realized it was money well spent. It sounds like a cross between the OB-X and OB-XA. We just wish it had a lot more knobs on it so we could program the darn thing!