Arguably the most famous guitar solo tone ever recorded. Gilmour's tone on the second solo of Comfortably Numb is built on a Big Muff Pi fuzz into a cranked Hiwatt, with delay adding depth and sustain. The Hiwatt provides clean headroom while the Big Muff does the heavy lifting for gain and sustain. The result is a singing, vocal-like lead tone that sustains endlessly.