The Oberheim OB-Xa was the second model in Oberheim's OB-series of polyphonic analog subtractive synthesizers. It replaced the OB-X and included new features.
History
The OB-Xa was released in December 1980, replacing the OB-X after just one year on the market. The OB-Xa was the first Oberheim product to have blue horizontal pinstripes on a black background, a design that became standard for future Oberheim products. The OB-Xa had the same number of voices as its predecessor (4, 6, and 8-voice models were available). However, its keyboard could be split into two parts, with each part using a different voice, or voices could be layered to create richer sounds (making two notes play for each key pressed). The OB-Xa also added the option to switch between 2-pole 12 dB and 4-pole 24 dB filters. It included Filter Envelope modulation for oscillator 2 (allowing the pitch to be controlled by the envelope), replacing the OB-X's ability to cross-modulate (changing the pitch of the first oscillator using the second oscillator).
Instead of using separate circuits for oscillators and filters, the OB-Xa and later Oberheim synthesizers used Curtis integrated circuits. This made the inside of the synthesizer less crowded, making it easier to fix problems and lowering production costs. It became harder to repair the OB-Xa due to the limited availability of Curtis chips. However, in June 2016, Curtis, Coolaudio, and Alfa began re-manufacturing some of these chips, helping to extend the life of the OB-Xa and other synthesizers that use these chips.
Notable OB-Xa users
List of Artists and Musicians
• The Carpenters
• Miles Davis
• Brad Fiedel
• Calvin Harris
• Billy Idol
• Jimmy Jam and Terry Lewis
• New Order
• Gary Numan
• The Police
• Prince
• Queen
• Robert J. Walsh
• Cliff Richard
• Rush
• Simple Minds
• Rod Stewart
• The Stranglers
• Thompson Twins
• Van Halen (a part of their 1984 song "Jump")
Hardware re-issues and recreations
In 2017, Behringer said it would copy the CEM3340 VCO chips used in the OB-Xa synthesizer. The wife of the chip creator, Doug Curtis, said the copy was made without permission. She also said Curtis would be very upset if others used his name or claimed their work was equal to his original inventions. In 2018, Uli Behringer announced that Behringer would make a copy of the OB-Xa called the UB-Xa. However, a shortage of microprocessors delayed the project. The next year, Behringer said the UB-Xa was ready to be made, and they also announced a desktop version. The first UB-Xa units were delivered in December 2023.
In May 2022, the Oberheim OB-X8, a new 8-voice analog synthesizer, was announced. This synthesizer uses the same voice design and filters as four classic Oberheim models: the OB-X, OB-SX, OB-Xa, and OB-8. It also includes features not found on the original models. The OB-X8 is made by Sequential in partnership with Tom Oberheim.