Oberheim OB-Xa

A 6-voice configuration of Oberheim’s famed OB-Xa, this version retains the big dual-VCO sound and split/layer capability in a slightly lighter chassis while offering the same rich Curtis-chip tone that defined early-1980s synth music.

Type
Polyphonic Analog Subtractive Synthesizer

Model
OB-Xa (6-Voice)

Manufacturer
Oberheim

Country of Manufacture
USA

Year of Introduction
1980

Controls
Pitch and Mod paddles, comprehensive front-panel knobs and switches for oscillators, filter, envelopes, modulation, split/layer, and program management

Input
(CV/Gate standard; many units later retrofitted with MIDI In)

Output
Left and Right 1 × ¼″ audio outputs (stereo or mono)

Power Supply
Internal AC (IEC connector)

Notable Features

• Polyphony: Fixed at 6 voices (two VCOs per voice)

• Oscillators: Saw and pulse waveforms with hard sync and detune

• Filters: Switchable 12 dB or 24 dB resonant low-pass filter per voice

• Envelopes: Independent ADSRs for VCF and VCA

• Bi-Timbral Operation: Keyboard split or layer two patches simultaneously

• Unison & Portamento: Thick mono lead mode and variable glide

• Curtis CEM Chipset: Delivers the signature OB warmth and punch

• Use Case: Ideal for classic ’80s pads, brassy stabs, and fat layered textures where authentic analog character is essential