Oberheim OB-Xa

The OB-Xa is the sound of 1982. Van Halen's "Jump," Prince's "1999," and Styx's "Mr. Roboto" all feature its massive, detuned oscillators and Curtis filter chips. Tom Oberheim designed it as a more reliable successor to the OB-X, and it delivered one of the fattest polysynth sounds ever produced. Eight voices of pure analog excess. The prices have skyrocketed — clean units fetch $15,000-20,000 — but nothing else sounds quite like stacking all eight voices into a unison brass patch.