Mentioned by Stewart in this Sound on Sound "Classic Tracks" interview about "Sweet Dreams (Are Made of This)".

On the same trip, in a hotel room in Wagga Wagga, New South Wales, Stewart began playing around with EDP’s Wasp synthesizer, accidentally stumbling upon the future, more electronic direction that he and Lennox were to pursue as Eurythmics. “I could actually get some interesting things happening,” he says. “Y’know, like, sequenced little sort of random hold patterns that sounded very exciting to us, even though it was just coming out of the plastic speaker in a crappy hotel room in Wagga Wagga. We weren’t even writing songs, I was just messing about on it.”

(...) Soon after, Lennox travelled to her native Scotland to visit her parents, leaving Stewart with time alone to further his experiments with the Wasp, pairing it with EDP’s matching proto-sequencer the Spider, and a TEAC 144 Portastudio. “I kind of voraciously learned how to use that really quickly,” he says of the latter, “and I realised it was little miracle. I had done things before, even before I met Annie actually, where I’d managed to get my hands on a Revox tape recorder, and I’d bounce things in a really crappy way, back and forth, and make a kind of montage of stuff.

“But with this Portastudio and the Wasp and the Spider sequencer, and then the [Roland TR-606] Drumatix, in one way or another I managed to manipulate the drums and the sequenced keyboard together. Then I was able to choose which sections I’d sequenced and sort of fly them over and bounce them. So I’m recording on track one with the sequencer, but then I’d sort of send it to track three or four and then I could switch it in and out when I didn’t want it. I could drop in if I wanted to change to a different chord or note or sequence. So I kinda built a track, kept bouncing back and forth. Some of them became the actual tracks on the Sweet Dreams album.”

According to the gear page on The Cassandra Complex website, Rodney Orpheus is listed as using the EDP Spider.