Beatles recording engineer Geoff Emerick has died of a heart attack. When John Lennon described how he wanted his voice to sound in “Tomorrow Never Knows” — “Like the Dalai Lama chanting from a mountaintop” — Geoff, 19 years old, had an idea.
… perhaps there was one amplifier that might work, even though nobody had ever put a vocal through it. The studio’s Hammond organ was hooked up to a system called a Leslie — a large wooden box that contained an amp and two sets of revolving speakers, one that carried low bass frequencies and the other that carried high treble frequencies… In my mind I could almost hear what John’s voice might sound like if it were coming from a Leslie. It would take a little time to set up, but I thought it might just give him what he was after.
From Here, There and Everywhere, by Geoff Emerick and Howard Massey
The effect can be heard at 1:27.