Simple but heavy, Jimi Page's riff is one of the undisputed roots of heavy metal music. This timeless simbol of rock is based on E power chords and typical Zepp's bluesy-hard rock style. Page played the loose blues riff for the intro, on a Telecaster through a 100W Marshall "Plexi" head amp with distortion from the EL34 output valves, which ascends into the first chorus.
Led Zeppelin's bass player John Paul Jones has stated that Page's famous riff probably emerged from a stage improvisation during the band's playing of "Dazed and Confused", but Page denied that: "No. No. Absolutely incorrect. No, it was put together when we were rehearsing some music for the second album. I had a riff, everyone was at my house, and we kicked it from there. Never was it written during a gig--where did you hear that?" And later explained: "I had [the riff] worked out already before entering the studio. I had rehearsed it. And then all of that other stuff, sonic wave sound and all that, I built it up in the studio, and put effects on it and things, treatments".