“Nothing was even mic'd up through the P.A. – they just listened to our amps and the two vocal mics. Sometimes we'd just play rubbish”: The Beatles on their struggles to be heard over the screams of Beatlemania – and the toll it took on their performances

(from left) Paul McCartney, George Harrison and John Lennon perform onstage on August 1, 1964.

Even if you know hardly anything about the frenzied years of Beatlemania, you probably have at least a vague image in your head of tens of thousands of screaming fans – overwhelming the sound of the Fab Four's live performances.

Technology, in every facet of life, has obviously advanced light years in the six decades since, and the world of onstage guitar amplification is no exception.