"Two 100-watt Marshalls. I set them full on everything, full treble, full bass and full presence, same with the controls on the guitar. If you've got the amp and guitar full, there is so much volume that you can get it 100 miles away and its going to feedback - the sustaining effect - and anywhere in the vicinity it's going to feedback." Eric Clapton, (Aug/Sept) 1967 (Rolling Stone, 1967).