"I found that some of my stereo CDs, when switched to "mono" mode on my amplifier, suffer a loss of highs and/or some comb filtering. Recording these in stereo in the LP4 mode created the same "phasey" sound as before. When I say 'phasey', I mean that the direction from which the sound is coming is obscure - ethereal might be a good word. If you're copying from a cassette tape and the tape is slightly buckled there will be a phase drift between left & right channels. This gives a "wandering' (truly ethereal) sound on LP4 replay."

The general meaning of the term is "spacey" - that it sounds simply weird. What the Beatles were actually doing here was putting their fingers or whatever on the reels of the tape while it was running, which of course makes the sound go a bit weird - or very weird.

It was very dramatic when it was first done, and it gave rise to a whole industry of creating time domain and phase effects with units made for the purpose, including the use that Hendrix etc. later made of them. (Phasing does not strictly speaking involve pitch change, by the way, but is often confused with effects that do. You get all of these when you mess with the tape reels while they are running.)

But when John (I think it is him) says "phasey" it is not a technical term, it is a description of the general weird effect you get when you interfere with a running tape in this way.