Thompson Twins – Quick Step and Side Kick

"For ages we used the OBXa because I accidentally found this brilliant bass patch on it. We used it on the Sidekicks album and I kept on getting phone calls to come and play bass on other albums."

Tom Bailey refers to the OB-Xa as his workhorse synth. He ​first acquired it in 1981 during the Set sessions, and used it on the underground Thompson Twins hit "In The Name of Love". Eventually it became a prominent feature of their music when they were at the peak of their popularity, on albums Quick Step & Side Kick, Into The Gap and Here's To Future Days.

According to Keyboard magazine August 1984 issue, 95% of the synthesizer sounds (including bass lines) on Quick Step and Into The Gap were played on an OB-Xa. The other 5% of synths were played on a Sequential Circuits Prophet-5 (by Joe Leeway) and a Pro One (by Tom Bailey). Plus, on Here's To Future Days, basslines were done on the OB-Xa and Nile Rodgers' Casio CZ-5000.

Effects-wise, the Oberheim is connected to an AMS reverb and a Roland Dimension D.

Live, Tom's OB-Xa was played by keyboardist Carrie Both on the Into The Gap tour.

In this photo from the early days of the Thompson Twins (i.e. the late 1970s), Tom Bailey can be seen playing a Fender Jazz bass.

This Fender Jazz bass (modified by luthier John Birch, according to roadie Stephen Dewey) was later used in the studio to add occasional bass slaps on top of Oberheim OB-Xa basslines on the Quick Step & Side Kick and Into The Gap albums.

As per this article:

'Loves Lies Bleeding' was a combination of three Oberheim basses and one real Fender for the slapping and tickling. The three Oberheims are doing different parts of the same line, accumulated as ideas: I thought the bassline should be like this, or like this, no, like this; what do they sound like all together? And then some slaps on the Fender on top as well.

This 1983 article states that Joe Leeway used a "rather problematic" Prophet-5 synthesizer. He acquired one from a duff batch of 500 or so, and never seemed to run for a week or two without going wonky. According to roadie Stephen Dewey, it was taken to the factory three times but they never repaired it. Eventually the Prophet-5 was replaced with the newer T8 model for the Into The Gap tour.

Joe Leeway used the Prophet-5 on the albums Quick Step And Side Kick (1983) and Into The Gap (1984) with the Thompson Twins.