Oberheim OB-Xa Synopsis

Duo-timbral with several updates

Voice architecture is dual osciallator subtractive with pink noise (i.e. VCO1+VCO2+noise->VCF->VCA). Oscillators can be sync'd. Poly and unison voice modes are provided

eBay Description

Key Features

1. Aftertouch: No
2. Architecture Class: subtractive
3. Audio IO: analog stereo and mono outputs
4. Audio Source: Oscillator waveforms are variable saw and pulse
5. Communication Interface: Tape in/out, CV in/out, Gate in/out DSX sequencer port
6. Effects: None
7. EG: VCF and VCA EGs have 1 level, 3 rates (i.e. ADSR) Filter EG can modulate VCO2
8. Expansion: None
9. Filter: resonant, low pass (2 pole) 2 or 4 pole
10. Form Factor: 61 keys
11. Key Scaling: filter cut-off
12. LFO: Destinations are oscillators, PWM and filter (0.1-20Hz). Dedicated "upper" and "lower" voice LFO waveforms are sine, square, and S/H. Additionally, dedicated vibrato LFO waveforms are sine, saw or square.
13. Memory:
• Multi Memory: N/A 16 (8 split, 8 layer)
• Patch Memory: 120
• PCM Memory: N/A
• Sample Memory: N/A
• Sequencer Memory: N/A
14. Multitimbral: No 2 (split/layer)
15. Pedal Inputs: volume, filter, vibrato, sustain, patch increment
16. Performance Control: chord memory, portamento, pitch and mod levers
17. Polyphony: 4|6|8
18. Power: AC
19. Released: 1980
20. Sequencer: No
21. Signal Class: analog
22. Velocity: No

Further Information

• Subtractive synthesis
• http://wikipedia.org/wiki/Subtractive_synthesis
• Analog synthesizer
• http://wikipedia.org/wiki/Analog_synthesizer
• OBSX:
• http://www.retrosynth.com/~analoguediehard/studio/keyboards/oberheim_obsx/
• OBX, OBXA, OB8:
• http://www.soundonsound.com/sos/sep98/articles/retro_oberheim.html
• Parts:
• http://syntaur.com/oberheim_ob.html

References

1. Released:
• http://vintagesynth.com
2. manuals:
• http://lazyblueoctopus.com
• http://manuals.fdiskc.com/flat/
3. MSRP:
• Vintage Synthesizers by Mark Vail

see Oberheim Gallery