The October 1964 single by the Beatles, “I Feel Fine” (included on their album Beatles ’65) is credited as the first song to use feedback in a rock recording.  The band was about to leave the recording studio when John Lennon left his guitar resting against his amplifier, only to be greeted by a whine of sound.  A feedback note was then added to the very beginning of the song.  In one of his last interviews, John Lennon spoke proudly of this musical innovation:  “I defy anybody to find a record . . . unless it is some old blues record from 1922 . . . that uses feedback that way.  So I claim it for the Beatles.  Before [Jimi] Hendrix, before the Who, before anybody.  The first feedback on record.” 

(July 2015)