[quote by=cash link=Blah.pl?b=songs,m=1093631406,s=2 date=1093637487]
the mystery continues[/quote]
Thats about right! I've read many articles and books that state Paul had struck an 'A' chord (I believe) on his bass and that fed through Johns guitar to cause the feedback. I've also read that John was using a semi-electric acoustic Gibson guitar (acoustic with a pick up) and that he leaned it on the amp without turning it off, in which caused the feedback. One of those mysteries in life we may never know.