3M M23 Tape Machine 1" Eight-Track. Purchased by John in 1968. The very earliest photos of Ascot Sound Studios show the M23 as the studio's sole multi track tape. The Beatles first used a M23 at EMI (Abbey Road) Studios in 1968 on "While My Guitar Gently Weeps" and would then go on to purchase three of their own M23s later that year. One of those machines, George's, would be used for the Let It Be sessions. According to Recording the Beatles "George can be heard explaining