IN 1948, a radio repairman named Leo Fender took a piece of ash, bolted on a length of maple and attached an electronic transducer.

You know the rest, even if you don’t know you know the rest.

You’ve heard it — in the guitar riffs of Buddy Holly, Jimi Hendrix, George Harrison, Keith Richards, Eric Clapton, Pete Townshend, Bruce Springsteen, Mark Knopfler, Kurt Cobain and on and on.

It’s the sound of a Fender electric guitar. Mr. Fender’s company, now known as the Fender Musical Instruments Corporation, is the world’s largest maker of guitars. Its Stratocaster, which made its debut in 1954, is still a top seller. For many, the Strat’s cutting tone and sexy, double-cutaway curves mean rock ’n’ roll.

But this heart of rock isn’t beating quite the way it once did. Like many other American manufacturers, Fender is struggling to hold on to what it’s got in a tight economy. Sales and profits are down this year. A Strat, after all, is what economists call a consumer discretionary item — a nonessential.