Few sounds in rock are as viscerally memorable as the growling twang of Syd Barrett’s guitar in the opening notes of Pink Floyd’s Interstellar Overdrive from the band’s 1967 debut album, The Piper At The Gates Of Dawn. Unlike the stratospheric, soaring tones that characterised later-era Floyd tracks with David Gilmour on guitar, Syd Barrett’s guitar sound is jagged, janky and wiry, somewhere between Vox and Marshall in voice.

The reason it’s a bit hard for the ear to pin down is that Syd used Selmer amps, which are collectible vintage items these days but largely forgotten by mainstream guitarists. The Treble And Bass model that Syd played on Floyd’s debut album is perhaps the best-known of Selmer’s 60s creations, but, for many years, the only way to capture the distinctive sound of that amp was to buy an old one and get it running reliably. For Lee Harris, guitarist with Floyd spin-off project Nick Mason’s Saucerful Of Secrets, that wasn’t really a viable option. With Nick himself on drums, the standard of sonic accuracy in the band, which performs songs from Floyd’s early albums, had to be high. So Lee decided to approach British effects maker ThorpyFX to see if the elusive tone of the Treble And Bass could be