It is similar to other keyboards in the OB series, but had a selection of presets rather than having a fully programmable interface. Prince liked working with these presets. As well as using one in the studio had his own OB-SX on stage on the Controversy tour.
Prince was incredibly bold in the way he would just use a preset and then brighten the fuck out of it! He would turn the filter way up so the sound would cut through the mix. I still have the OB-SX from those days. It’s one of the most simple Oberheims - there are just a few knobs on it, but that was the most quintessential keyboard from that era.
Prince continued using the OB-SX on the 1999. The song Something In The Water Does Not Compute features multiple stacked OB-SX parts . Prince used a collection of Oberheim synthesizers into the mid-1980s, and the OB-SX probably appears on the Purple Rain, Around The World In A Day, Parade and Sign O The Times albums.
Dez Dickerson played one in the Let’s Pretend We’re Married video.