I had to do some research to find out how the Beatles got the sound and then to see how others have over come the problem... this is what I dug up for ya...
The dirty guitar sound was created by plugging the guitars directly into the audio board. The guitar sounded so scratchy that many who bought the 45 RPM single tried to return it, thinking it was defective. (thanks to Dwight Rounds, author of The Year The Music Died, 1964-1972)
Some more heavy reading on the subject can be found here..http://en.wikipedia.org/wiki/Revolution_(song
And finally I ran a few chords thru the computer and yup... it was Fuzz... I set the level on a few chords and found that the riff played there was about half way on dial.
Went thru a lot of reading on it and even watched some videos there on the net.. Found a bunch of interesting things about the song too.. Never knew that it had so many stories on the recording just because John and Paul disagreed about even making the song.