Without Les Paul, there might never have been an electric guitar - and at 93, he's still looking for new sounds. Ed Pilkington meets a true rock'n'roll pioneer

It could only happen in New York. Where else in the world would people queue around the block for a seedy-looking jazz club, to hear the performance of a man best remembered for having invented the musical broomstick, whose fingers are so arthritic they can hardly move, and who is still pumping it out every Monday night at the age of 93?

But then, the weekly Les Paul show at the Iridium Club, a basement joint on Broadway that looks as though it was set in aspic some time in the 1950s, is more than just a performance. It's a pilgrimage, where fans of 20th-century American music and lovers of the electric guitar - Paul McCartney, Jeff Beck, and Keith Richards among them - come to pay homage to the great man. Richards bluntly summed up the aura of the man when he said: "We must all own up that without Les Paul, generations of flash little punks like us would be in jail or cleaning toilets."

Like his close collaborator, Leo Fender, Les Paul is best known for the electric guitar he created. If the Fender Stratocaster is the edgy workhorse of the rock industry, the Gibson Les Paul was and remains its elegant rival, its richly varnished mahogany body and oyster-shell fingerboard adding a touch of class to a rough-hewn affair. But there's much more to Paul than a lump of wood with a cherry-burst finish: he's also a consummate musician who, despite the arthritis which has reduced him to the use of just two fingers, is still able to spark a flame in much younger performers. The night I go to the show, Paul is joined by guitarist Joan Jett, who looks like a frightened rabbit as she takes the stage. But Paul quickly loosens her up, quipping when she plays a blues riff: "That's a little before my time."

The joke is that Les Paul's time has been pretty much any decade since the 1920s. As a new documentary about his life, Chasing Sound: the Les Paul Story, spells out, the life of the man is nothing less than a history of modern American music, from the hillbilly of his boyhood, through country music and jazz, into the era of radio and TV broadcasting.

Paul's uniqueness is that he is both a brilliant musician and a brilliant sound engineer. (He is currently trying to develop the perfect hearing aid.) Aged eight, he found music after he was given a harmonica by a local sewer digger in his home town of Waukesha, Wisconsin. He started singing, and then added a guitar. His hillbilly act was popular among school friends and teachers, and this bred a curiosity about devising new ways of amplifying himself to a larger audience.

"From the very beginning the two sides - music and sound reproduction - were always equal," he tells me as we sit backstage at the Iridium. "My mother used to say, 'Lester, that's very good, that's real commercial.' And I'd say, 'But mum, I can't hear clearly what I'm playing - I'd have to be sitting where you are listening to do that.'"

When he was about 13, he played at a barbecue stand outside Milwaukee. By then he had found a way of rigging up his mother's telephone, singing into it to the speakers of the family radio. "People loved it. Except one guy at the back of the crowd who wrote to me to say: 'Red [his nickname], your voice and your jokes and your singing were fine, but your guitar wasn't loud enough."

That began a search for the perfect amplification. Early experiments involved putting a needle from the family phonograph under the strings of a guitar. He also stuffed the guitar's hollow box with sheets and rags, and then plaster of Paris, in an attempt to muffle the feedback, but in vain.

He had a breakthrough when he tried the most dense piece of material he could find, a piece of railtrack, attaching it to a guitar string and a telephone receiver wired up to a radio. "It sounded great! I ran to my Mum and shouted 'I've got the answer!' And she replied: 'Did you ever see a cowboy on a horse playing a railroad track?' So that put that idea right out of the window."

It took many more years of tinkering before he made his first solid-wood guitar, in 1941; he had to wait another 10 years before Gibson finally embraced the idea, in 1951. "The electric guitar was laughed at! They called me the character with the broomstick with pick-ups on it. It was terrible. Before we came along the guitar was an apologetic wimp - the weakest, most unimportant guy in the band. As soon as we put a pick-up on him, and a volume control, he became the king."

Meanwhile, Paul's career as a musician was going through similar stops and starts. He played with the greats of his generation: Bing Crosby, the Andrews Sisters, and was one of the few white musicians to cross over into black jazz, playing alongside Art Tatum, Nat King Cole and BB King. Not bad for a man who has never been able to read music.

With his wife Mary Ford he forged a legendary double act, producing hits How High the Moon and The World is Waiting for the Sunrise. He developed a fast, intricate virtuoso technique, not dissimilar to that of jazz guitarist Django Reinhardt - but when others copied him he went looking for fresh sounds. He pioneered the use of multi-track recording, layering voice upon voice to create what he called, appropriately enough, the New Sound.

Like his guitar, this find initially met with blank stares. "There are always people who don't want to make changes, who are set in their ways," he says. "It's just the same today. We know we are going to find new and better music. We wouldn't be happy if it were to change back to Bing Crosby or Les Paul or Mary Ford, or whatever it was. Nothing wrong with it, but it's gone. There's a new kind of music, and it's on its way".

Chasing Sound: The Les Paul Story, is released on DVD on September 29 by Eagle Rock Entertainment