Queen's guitarist's distortion..

What is it?, I love its sound!

weeeeeeeeeeeeeeeeeee

I am by no means an expert, but at one point Brian May had a fuzz box installed on his original Red Special design. Eventually he fell out of favor with it and placed black tape over the red button to blend in with the pickguard. I assume he has since had it removed. However, he stopped using the feature very early in his career and I doubt this is the sound to which you are referring. It probably has something to do with a specific effect pedal or amps he used. He is partial to VOX amps, vintage, and has a smaller guitar amp he uses that was contructed by Queen's bassist, John Deacon...affectionately dubbed the 'Deakie' amp.

According to another thread on here Brian May would use a dime or 6 piece for a pick. That would give it that metallic edge that you hear.

Copying May's sound must be an almost impossible task.
I mean, he buildt his own guitar out, and has used weird effects combinations all of the time. And his playing style is awesome.
Don't forget that the fingers also makes the sound.

May's sound, i agree, would be impossible to copy. He uses an english Sixpence (about the size of a quarter) as a pick, and it's serrated edge gives it the bite you hear. His amp is custom built by john deacon, the bass player. He has said that to get extra warmth, he throws a jacket over the amp and records it that way. He tubes in his amp give him the sound he is famous for. His guitar also has about 40 tone combinations built into it

He actually uses ac30s as well as his custom made one.

Yeah, the "Deacy" amp is only for certain overdubbing tasks (the "trumpet" noises in Queen's guitar orchestrations). He uses nine AC30's in his live rig nowadays.

this might help: http://www.voxamps.co.uk/products/brianMay.htm