Interesting thread on VSE on the Oberheim OB-SX including sample, pic and some intesting manufacturing history.
"Yep, that's an earlier version of the OB-SX, just like CTB says above.
This model was first shipped in Sept 1980 and remained in production until sometime in the first part of 1981 when it was replaced by the Mk II version which came in the same color-scheme as the OB-Xa.
The earliest production run of the OB-SX came with discrete VCA's whereas later ones were all-Curtis (like the OB-Xa). Note also that the OB-SX had only one 3320 filter (connected in the 2-pole fashion*) as opposed to the two filters found in the OB-Xa (one set to 2-pole, the other to 4-pole).
The serial number on the OB-X, OB-Xa, DMX, DSX and OB-SX consist of 6 digits; the first two (eg "81") represent the year of manufacture, the following two (eg "40") indicate in which week of that year it was built. I'm not quite sure about the last two digits, but I reckon that for example a unit having "01" at the end of its serial number would have been the first unit being built in that particular week. This serial number system is very convenient when you want to date a particular specimen. Later products like the DX, DX-1a (a later DX sporting midi) as well as the OB-8 used a similar serial no. system except, for some reason, the first digit "8" was replaced by the letter "B" (sometimes "C").
* so you won't get that big punch that the OB-Xa is known for.
"
The sound samples do sound amazing though.
