Dudley Simpson

"Yamaha organ and, later in the year, EMS VCS3. But even that is confusing. In Spearhead from Space for instance, there is stuff that sounds like a synth, but it's actually a French Horn mixed through a phase shifter."

Mark confirmed some synths that Dudley Simpson used for Dr Who since he knew him and talked to him personally.

"Oh, and Baldwin Electric Harpsichord playing spooky low notes."

Mark Ayres confirmed Dudley Synths he used in Dr Who, since he knew him and talk to him personally in the past.

Mark Ayres confirmed on Gearspace that Dudley Simpson used the Moog Polymoog Synthesizer 203a for the series "Blake 7."

As he quoted and answered to cherry audio thread about what synths Dudley used.

Dudley Simpson is confirmed to have used the EMS Synthi 100, also known as "Delaware," during the Jon Pertwee era stories. This was verified by Mark Ayres, who confirmed the specific synths Simpson employed.

As he quoted "EMS VCS3, and later the massive Synthi-100 "Delaware"."

In the video titled "Radiophonic Workshop | The Music of Doctor Who | Me, You and Doctor Who | Doctor Who" on YouTube, it is stated at the 0:32 mark that Dudley Simpson used the Yamaha Electone EX-42 for several Doctor Who serials during the Jon Pertwee and Tom Baker eras. However, the BBC lost the original keyboard a long time ago, which led Mark Ayres and other performers to recreate a cue from "The Talons of Weng-Chiang."