A Revolution?

There's a huge buzz going around about the "newly discovered" version of the Beatles' Revolution that appeared online this week.

I've listened to it a few times now and here's what I know:
It's labelled "Take 20," but it is clearly not a rough take. It has the same "Take two" edit as on the album version, John's voice sounds like it's been ADT'd and there are obviously overdubs. Not the kind of thing you do on a discarded take.

According to Mark Lewisohn's The Complete Beatles Recording Sessions (the last word on all such matters), take 20 was in fact a tape reduction of take 18.
Huh?
Well, the Beatles only had 4-track tape machines at the time. So once the first three were filled up, they were mixed down to the fourth track and the other three were then re-used. This actually happened three times during the recording of Revolution 1. So all you hi-fi buffs take note - even the master recording is third generation! The "Take 20" announcement that we hear is for the benefit of the tape and was not part of the live recording session. That would explain the dropouts at the start of the leaked recording.

Even though take 18 was a long and meandering version of the song, they evidently overdubbed the whole of it - at least the first overdubs, anyway. There's not evidence on the newly discovered Take 20 of the brass section that was added later. And yes, some of the ad libs at the end were later used for the sound collage, Revolution 9.

So what we are hearing is the full length version of what would eventually be cut down to make the album version. Definitely a curio worth having if you can still find it.