Without doubt, one of the best synthesizers ever made.

The Oberheim Xpander is legendary for being one of the greatest analog synths of the 80's era. It represents the pinnacle of achievement in the era in terms of programmability. It is essentially a modular synth that is configured through a sophisticated modulation matrix. it can be used in poly mode, but each of its six voices are also independently configurable. Combined with its individual outputs, the Xpander is sort of like having 6 computer controlled modulars in one box.

No mention of the Xpander would be complete with a discussion of its filter; a multimode filter that provides no fewer than 15 (!) configurations, including low pass, band pass, high pass, and various combinations. There are few, if any analog synths other than the Xpander and its keyboard cousin, the Matrix 12, that have a filter this flexible. (Notable exception: the Mutable Instruments 4-Pole Mission filter offers a similar design.)

All of this comes at a cost: the Xpander is not cheap. At the time of this writing, they are generally around $4000. Additionally, the Xpander's use of rare filter chips and VFD displays makes it a risk in some ways: parts are difficult, if not impossible to find. Those interested in achieving something close to its sound without making such a serious investment might check out a Mutable Instruments Ambika with the 4-Pole Mission filter boards.

Lastly, those dying to own an Xpander should be on the lookout for the American-made version. Perhaps paradoxically, the Japanese-made units were not as well made, and the modern VFD display replacement that is made for the Xpander will NOT work with Japanese models. for this reason, Japanese Xpanders should be avoided as they will be harder to future-proof. Japanese Xpanders can be identified by looking at the back panel. On Japanese models, the legends describing the purpose of the various jacks are below the jacks, as opposed to the U.S. made versions, where the lettering appears above the jacks.

One of my favorites

Xpander has - fat drone, piercing lead, rich timbre.