There are a number of videos on youtube focusing on the inside of Abbey Road. For example, here is "Native Instruments' Abbey Road 60s Drums" session. Worth watching if you want to get an idea of how those glorious tones werer captured.
http://www.youtube.com/watch?v=f4JLz316ALw So, if you think people are obsessed about The Beatle's sound, you under-estimate. Here are some technical articles by a Canadian mathematician who used a Fourier Transform to dissect the opening chord of A Hard Day’s Night:
http://www.mathstat.dal.ca/~brown/n-oct04-harddayjib.pdf And also to show (again using a Fourier Transform) that the George Harrison guitar solo in A Hard Day's Night was actually recorded at half speed:
http://www.mathstat.dal.ca/~brown/AHDNSoloJIB.pdf Me