The Doktor has gone through a number of incarnations during his career, beginning life as a Boss DR55 'Doctor Rhythm' machine. The Doktor became a Roland Drum Machines TR606, then a TR808, and, briefly, a TR909. The Doktor transformed into an Oberheim DMX for the band's first album.
By the time of "Floodland", the Doktor became a Yamaha RX5 to accompany Andy's new computer and sequencer combo. By the time the album was recorded, the Doktor transformed into an Akai S900 sampler. These days, the Doktor maintains two forms, an Akai S1000 sampler onstage and an Akai S3200 in the studio.
When not providing the band with their characteristic drum sounds, the Doktor also writes the Dear Doktor column on the band's homepage.