{"id":2542,"date":"2008-02-07T20:55:12","date_gmt":"2008-02-07T19:55:12","guid":{"rendered":"https:\/\/www.sequencer.de\/blog\/?p=2542"},"modified":"2025-08-03T22:11:11","modified_gmt":"2025-08-03T20:11:11","slug":"oberheim-x-series-obx-obxa-ob8-dmx-dsx-prommer","status":"publish","type":"post","link":"https:\/\/www.sequencer.de\/blog\/oberheim-x-series-obx-obxa-ob8-dmx-dsx-prommer\/2542","title":{"rendered":"Oberheim X-Series: OBX, OBXa, OB8, DMX, DSX PROMMER"},"content":{"rendered":"

OBERHEIM X Synthesizer Series
\n<\/strong>OB-X OB-Xa OB-8 DMX DSX PROMMER
\n<\/em>
\n<\/strong> back to OBERHEIM SYNTH MENU – zur\u00fcck zum OBERHEIM SYNTHESIZER MEN\u00dc<\/strong><\/a><\/p>\n\n\n\n\n\n\n\n\n\n
the Oberheim X System Line<\/td>\n\"Oberheim<\/td>\n<\/tr>\n
<\/a>OBX<\/a><\/font><\/p>\n

<\/strong>difference Oberheim
\n<\/em>OB-X<\/a><\/font> vs. OB-Xa<\/p>\n

OB-X<\/a><\/font> = discrete analogue circuitry, possibly SSM?
\nOB-xa<\/a> = Curtis Chips<\/a>the OB X<\/a><\/font> wasn’t part of the x-system all x-synthesizers
\nare compatible optically and dimensions<\/p>\n

the ob-x has Crossmod which never came back on the later machines ob-x and ob-8<\/p>\n

the xa<\/a> 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..
\nthe OBX has Crossmod. the OBxa<\/a> hasn’t, but the OBx has no self oscillating filters (12dB\/oct is often limited to non max reso\/self oscillating)
\nOBSX:
\na preset version of the OBX<\/p>\n

find a nice pic\/brochure and largest pic on the web of the OB-X<\/a><\/font> here::
\nBernhard D\u00f6rings Synth site<\/span><\/td>\n

\"Oberheim<\/a>
\nenlarge oberheim <\/font><\/em>OBX<\/a><\/font>? just click it!
\n-all obx pics thanks to theo bloderer \/ bluesynths.com<\/a>
\n\"Oberheim<\/a><\/font><\/em>
\n\"Oberheim<\/a>
\none voice can be controlled from the back.. click pic!<\/em><\/p>\n

\"Oberheim<\/a>
\nOBX Envelopes..
\n\"Oberheim<\/a><\/td>\n<\/tr>\n

<\/a>Oberheim <\/strong>OB Xa<\/a>.. the jump synth (uaa I hate to mark it like that).. better mention it was played by Depeche Mode…!!)
\nAlso there was an Expander „xpander“ version available .. don’t confuse those with THEEE Oberheim Xpander (see above)<\/p>\n

<\/a>btw: thanks to axel fischer for help.. (the ob Xa was „in may way“ at his house))<\/p>\n

<\/font><\/p>\n

this machine is part of the X-System
\n(DMX drums,
\nDSX sequencer
\nOB-Xa synthesizer)
\n1980, 2 VCOs
\n1 LFO (20hz max)
\nand 2 ENVs
\nall quite standard
\nno FM \/ ringmod.<\/p>\n

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..<\/td>\n

\"oberheim<\/a>
\nOBxa<\/a> Problemzone: Nach Best\u00fccken und Verl\u00f6ten der Bauteile auf den Platinen wurden sie in ein chemisches Reiningungsbad gesteckt, gegen dreck.
\nwirkung: nach einiger Zeit wurden Trimmpoti-Oberfl\u00e4chen angegriffen und die Widerstandswerte schwankten daher. ICs wurden per Sockelsteckverbindung befestigt, wg. besserer Servicefreundlichkeit. auch die Kontakte in den aufgel\u00f6teten Steckverbindungen bekamen Kontaktschwierigkeiten.
\nwas tun? Alle Trimmpotis und IC-Sockel raus, neue Potis und die ICs reinl\u00f6ten.
\nInformationen von Tom Oberheim \/ Marcus Ryle.<\/font><\/em>
\n\"Oberheim<\/a>
\nclick image to enlarge..
\n<\/font><\/em>LPF 12dB\/oct oder 24dB\/oct.
\nself reso.
\nresolution 64steps = 6bit
\nosc sync
\nno xmod(ringmod or FM
\nhas chord memory, 32 RAM , up to 120 memories.
\nLFO with s\/h
\nunison mode, split and double also.
\nno midi, that was the new thing in the ob8 „obie eight“..<\/font><\/em><\/td>\n<\/tr>\n
<\/a>OB 8<\/a>
\n<\/strong>
\nquite close concept to ob x.. the classic oberheim
\nsee the midi ports?\"oberheim<\/p>\n

OB8 <\/a> quite same features as OBXa.. but a bit more and midi..<\/p>\n

structure:
\nswitchable 2 or 4 pole LPF (low pass filter), 8 voices (instead of modular voices expandable like the obxa) with 2 VCOs (saw,pulse,tri), syncable, arpeggiator and lfo. splitable, 120 patch memories. (de)tune each voice and let them sound unison! standard version has NO midi, later version have like the model shown here. It was made from 1983 to 1985, maybe the DX7 was a big opponent (remember: the ppl wanted „realistic“ e pianos , haha) but this is the „jump“ synth.. or better: the ob xa is the jump synth, this one is,too ;) but it CAN sound gooood!! this one got famous for it’s pads, „brasses“ etc.. oberheim did one of the best sounding and warm curtis<\/a> based synth. like the xpander it has a very warm sound and very easy to use,
\nthanks for photos by P.M.Mahr <\/font>from<\/font><\/p>\n

<\/font> http:\/\/<\/font>www.twicethemovie.com<\/span><\/font><\/em><\/p>\n

OB8<\/a><\/td>\n

\"Oberheim<\/a>
\nclick image to enlarge..
\n<\/font><\/em>
\n\"Oberheim<\/a>
\nclick image to enlarge..
\n<\/font><\/em>
\n\"Oberheim<\/a>
\nclick image to enlarge..
\n<\/font><\/em>want nice filter modulation by VCO? <\/span>check j.haibles mod
\n<\/font><\/em><\/p>\n

2 VCOs and ARP’er and detunable voices (faaaat!)
\nmidi .. the coolest kit had 9 channels (retrofittable)<\/p>\n

timeline 1974 – 1986:
\nSEM\/2,4,8voice -> OB I -> obx -> obxa -> ob8
\n-> matrix and xpander line<\/p>\n

the OB-8<\/a> added some features on „page 2“ (double „click“ the chord memory button) like LFO key sync for phase control \/ retrigger modes, LFO quantize and more – the OB8 has at leasst 3 LFOs, 2 because you have 1 LFO per layer and another one „non programmable“ on the mod \/ wheel section (called lever @ oberheim).<\/p>\n

the ob8 is the most powerful one in the OB series (obx,oba,ob8) but also has not xmod like the obx.<\/td>\n<\/tr>\n

the sequencer DSX, another part of the oberheim Xa\/DX series.. (drum machine dmx,the obx synth and ob-x\/xpander – unfortunately there has been another xpander but they sold it as „ob Xpander“.. looks like THE xpander but with the knobs and tech. specs of the X of course..)the X System connectors are a 2 „Blocks“ of Connectors (2 white very unusual sockets with lots of pins, one for trigger one for CV)<\/td>\n\"DSX
\n\"DSX<\/td>\n<\/tr>\n
the early digital Sequencer
\non the left: the analog step sequencer that came with some of the X-Voice models,<\/p>\n

below: filtermodule (external)<\/p>\n

see more on this design in the SEM<\/a><\/font> section..<\/p>\n

click to enlarge –><\/em><\/td>\n

\"Oberheim<\/a><\/td>\n<\/tr>\n
the DMX<\/a><\/font> belongs to oberheims „x-system“. one of those 12bit drummachines. the category is same as linn drum, drumtracks, drumulator etc..there were 2 versions, the „stretch DX<\/a><\/font>“ (mid \/ above) and the (right \/ below) DMX
\nclick to enlarge –><\/em><\/p>\n

triggering DMX<\/a><\/font>:
\nif you have a trigger out (like eg. one of the three trigger outs of a tr808) you could trigger: directly and DIY yourself some of those trigger interface pins.. or easier: use the clock in to trigger the machine , set eg the cowbell of the 808 every step = on and you have a perfectly in sync DMX.. the clock in should be the leftmost jack seen from the back..<\/p>\n

most oberheim drummachines do not have midi since they had their DX<\/a><\/font> system (or DMX system..)<\/td>\n

\"Oberheim<\/a>
\n\"oberheim<\/a><\/td>\n<\/tr>\n
<\/a>Oberheim OB Prommer<\/a><\/strong><\/p>\n

basically some sort of self burning sampler for these drum machine models:
\nSCI DrumTraks<\/a>, LinnDrum, Oberheim DMX\/DX, Hammond Sakata and Simmons<\/p>\n

burning your 8bit samples to an EPROM (electrical programmable read only memory) – typical mid 80ies style..<\/td>\n

\"Oberheim<\/a>
\nclick <\/font><\/em>Prommer<\/a> image to enlarge..
\n<\/font><\/em>thx viewermail studio for pic!<\/p>\n

fill other machines with your samples..
\n<\/font><\/em>\"mxr<\/a><\/td>\n<\/tr>\n<\/table>\n