OB-Mx

Designed by Don Buchla as his final Oberheim project, this 1994 module packs the legendary fat tones of classic Oberheim and Minimoog filters into a rackmount powerhouse that's begging for a comeback in modern setups.

Rack-sized at 480mm wide by 220mm high and 200mm deep, it starts with two voices per card—each boasting dual VCOs, dual VCFs (a 12dB/octave state-variable OB filter with low/band/high-pass modes, plus a 24dB/octave Minimoog low-pass), a VCA, four multistage envelopes, three LFOs, and a mixer—all fully analog in the audio path with digital control for precision. A modulation matrix, 12 modulation patches, and a 2-line backlit LCD make programming intuitive, while 256 single patches and 256 performances support 6-part multitimbrality. Expandable to 12 voices via plug-in cards, it offers four stereo outs and full MIDI, perfect for layering those warm, aggressive sweeps.

Owners cherish its OB-series heritage and upgrade potential, though some note the filters can feel thinner than vintage counterparts—still, artists like Nine Inch Nails and U2 found its phat edge irresistible.