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 OBERHEIM OBXa Analog Synthesizer

Oberheim OBXa synthesizer
moogulator ob-xa
click image to enlarge - Bild klicken zum vergroessern
other OBERHEIM gear..
Built 1981
Type: analog
Hybrid: no
8 Voice / Stimmen
2x Multitimbral
standard Memory / Speicher
Value / Wert in 2017 ca. 1100 (rare)
Synthesis: subtractive

OSC Features pwm sync
Wave Shapes pulse saw noise
2 OSCs
1 Filter lpf reso 2-4 Pole
1 LFOs sine square s+h
2 Envelope Generators 2x ADSR

NO Control / Triggering
61 Keys with no

Arpeggiator no
Sequencer no
(ID 185)
  deutsch - german
ABOUT successor of the OBX, more reliant and well known classic synth (just mention "jump" by van Halen, but better say Depeche Mode..), also some improvements.. this machine is part of the X-System (DMX drums, DSX sequencer OB-Xa synthesizer) 1980, 2 VCOs 1 LFO (20hz max) and 2 ENVs all quite standard no FM / ringmod. the obx was it's predecessor in 1979 and is the rarer one of both. - it is now famous for the "jump" sound of van halen - but it is not just "jump", some brasses and pads.. it's like the oberheims are: fat and warm. very "broad and wide" sound! thats they key .. and maybe explains the success in the 80ies! it's still big in sound..
ABOUT Der Nachfolger des OBX, noch etwas verändert und ein Klassiker (ich sag mal "Jump" / van Halen), aber natürlich auch Depeche Mode (besser!). Das X-System war eine ganze Serie von neuen Oberheim-Synthesizern (Xa und "OB-Xpander"-nicht baugleich mit dem Xpander, sequencer (DSX) und Drum-machinen (DMX und stretch version)
DETAILS allows V/Oct control.still very good sounding, still. unison mode! and split mode. 2 and 4 pole modes. difference Oberheim OB-X vs. OB-Xa OB-X = discrete analogue circuitry, possibly SSM? OB-Xa = Curtis Chips the OB X wasn't part of the x-system all x-synthesizers are compatible optically and dimensions the ob-x has Crossmod which never came back on the later machines ob-x and ob-8 the Xa added a split/double mode and was expandable from 4 to 8 voices with 2-voice cards.. and it also had 2 and 4pole filters, the obx had no 4pole mode.. the OBX has Crossmod. the OBXa hasn't, but the OBx has no self oscillating filters (12dB/oct is often limited to non max reso/self oscillating) OBSX: a preset version of the OBX LPF 12dB/oct oder 24dB/oct. self reso. resolution 64steps = 6bit osc sync no xmod(ringmod or FM has chord memory, 32 RAM , up to 120 memories. LFO with s/h unison mode, split and double also. no midi, that was the new thing in the ob8 "obie eight".. Hardware: (obxa/ob8) 2 CEM3360 Dual VCA 16 CEM3340 VCO 16 CEM3310 EG 16 CEM3320 VCF
DETAILS V/Oct steuerung., gut im sound. unisono mode und split mode (endlich). leider kein midi (gabs ja noch nicht), 2 und 4 pol mode. OBXa Problemzone: Nach Bestücken und Verlöten der Bauteile auf den Platinen wurden sie in ein chemisches Reiningungsbad gesteckt, gegen dreck. wirkung: nach einiger Zeit wurden Trimmpoti-Oberflächen angegriffen und die Widerstandswerte schwankten daher. ICs wurden per Sockelsteckverbindung befestigt, wg. besserer Servicefreundlichkeit. auch die Kontakte in den aufgelöteten Steckverbindungen bekamen Kontaktschwierigkeiten. was tun? Alle Trimmpotis und IC-Sockel raus, neue Potis und die ICs reinlöten. Hardware: (obxa/ob8) 2 CEM3360 Dual VCA 16 CEM3340 VCO 16 CEM3310 EG 16 CEM3320 VCF
SOUND wide and big pads and sweeps with soft character, one of the best you can get. leads and basses also very fat.
SOUND flächiges und tolle sweeps, fette Leads und Bässe.
VERSION versions 4, 6 or 8 voices.
VERSION Versionen mit 4, 6 oder 8 Stimmen.

OBERHEIM or Gibson, Oberheim-Viscount Joint Venture, Viscount

today owned by Gibson and lendet to Viscount. Tom Oberheim started it (of course he left when Gibson took over). He built Synth Modules (SEM) to be played via other synthesizers and ppl wanted him to built synths: he did. he took SEMs and made polyphonic synths out of them. the latest synth was the Xpander and Matrix12, the OB-Mx wasn't a real Tom Oberheim anymore, so they got Don Buchla finishing it (it did not sell well), so the OB12 as only the name in common with the founder. Mr Oberheim tried again under the Marion System name.

The "real" Tom Oberheim is now producing under his full name guess his site -

Offizielle Site (D)


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