In the late-1990s, Thom switched between two pedals for acoustic guitar distortion: an original Tech 21 Sansamp and a ProCo Turbo Rat. His acoustic guitar pedal was kept to the left of his mic stand, while his electric guitar pedals were kept to the right of his mic stand. He only had a single pedal on his left during that era, using it for Paranoid Androidand Climbing Up The Walls. Thom can be seen stomping on the Sansamp during Paranoid Android on Jools Holland, filmed on May 21, 1997. However, Thom is instead using a ProCo Turbo Rat in footage from Radiohead’s appearance at Eurockéennes de Belfort on July 4, 1997. The distortion on that performance sounds pretty similar to the distortion on the Hammersmith (10 Spot) recording from December 19, 1997, so he most likely used the Turbo Rat for both.
Also, make sure not to confuse Thom’s acoustic guitar distortion, heard at the end of the song, with Colin’s fuzzy Novation Bass synthesizer, heard throughout the song. No amount of distortion will make an acoustic sound like the blend heard at the end of Climbing Up The Walls: the layering of Colin’s synth bass, Thom’s distorted acoustic, and Ed’s distorted electric.
A photo of Thom during Radiohead’s BBC Radio 1 session on May 28, 1997 (Tom Sheehan). We can see his Tech 21 Sansamp on the floor to his left, and his electric guitar pedalboard on his right (featuring a Boss DD3, Marshall Shredmaster, and ProCo Turbo Rat). This was just a week after the Jools Holland performance, so it’s no surprise he’s still using the Sansamp for his acoustic. Compared to the later performances mentioned above, the distortion sounds a little less extreme in the BBC session.