"This 8-voice model Oberheim OB-X is fully functional and in good cosmetic condition.
The OB-X is the first in the OB line of synthesizers from Oberheim. These advanced the concept of polyphony from the SEM expansion method of the Two, Four, Eight Voice synthesizers to a series of internally expandable voice cards. The OB-X still retains the SEM filter design rather than the Curtis chip filter of the later models in the OB line."