Paul McCartney has shared a unique glimpse into his recording process, revealing that he still uses an amplifier that he bought when he was aged 14.The Beatles icon showed off his ‘Little Green Amp’ – the Elpico A55 – as part of an hour-long tour of his Hog Hill Mill Studios in east Sussex, which is included in the re-release of his 1997 solo album ‘Flaming Pie’.The Elpico amplifier has become part of Beatles folklore in its own right, and was seen on stage with the band throughout their