To me, meeting Buddy Guy was like meeting a piece of history.

Most people can do what I do - they can do guitar solos - but they can't do a good, hard rhythm guitar and be dedicated to it.

I never thought we'd be put into any sort of historical thing. When we started as a band, it was a day-to-day thing. You sort of played a gig, you got your money and thought, 'OK, where's tomorrow's gig?' You never thought you'd get past a summer.

Go back to the very beginning, when we first started playing in local pubs. We used to play Chuck Berry covers. Every now and then, we'd slip in one of our own songs, and we found that we were getting away with it - nobody seemed to know these were original tracks.

I have this theory about us. When we started writing our own songs, we were 17 years old. When you're 17, you write songs for other 17-year-olds. We stopped growing musically when we were 17. We still write songs for 17-year-olds.

We've always been quite clear about how we want the songs to sound. If we can imagine the song being played at a party, and it gets people tapping their feet, then it's in.

We knew when we started we wouldn't be accepted overnight, that it was going to be a long haul.

Riffs are a repeating thing. They come back to you. Some of the things on 'Back in Black' were ideas we had knocked around on tracks before that: 'That bit - maybe we should take a chunk of that and slug it in here.'

In the studio, my brother and I have always used a lot of Marshall amps. We like to keep it pretty basic. We just use a couple of cabinets each - sometimes just one, if we think that's enough. We mainly go for 100-watt and 50-watt heads.

With guitar riffs, we always look for something that 's a little bit special. We've always found that it is harder to come up with something that's nice and simple without getting something that's hard but easy.