Engineer Andy Johns on recording and mastering Led Zep IV: 'I put the tape on and the first song goes by and sounds bloody awful. Then the second one comes along and that's really horrid, too... Pagey should've fired me at that point'

Byline: MusicRadar 'Pagey was going on about seeing ghosts on the stairs and we were like, 'Oh yeah right, Jimmy!'' By the time Led Zeppelin holed themselves up in a [...]