tracking distortion on a p5 + rega cartridge?

You will probably have to sight the cantilever of the cartridge using an alignment protractor.Not all cartridges are perfectly manufactured and cantilever alignment can quite often be out of true,this is one problem with Rega's system.I prefer to eyeball the cantilever and align that way rather than using the the body as it is more accurate.

here is a 10 sec sample of the problem:

http://www2.skwire.net/~AYB/edna/excerpt.mp3

Is this a digital or analog recording?Your bass sounds possibly too "fat" and your cymbals possibly "dull".This could be due to firstly an incorrect tracking weight and then the VTA would have to be adjusted accordingly.I don't think Rega's have VTA adjustment,but go to the Walker Audio site and you will see a link to fine-tuning your table,on the left.I don't think you would totally get rid of the noise but there is plenty of info about correct alignment,overhang,azimuth etc. for the Rega arm over at the Vinyl Asylum archives.

"Your bass sounds possibly too fat and your cymbals possibly dull."

Actually, that is how the music should sound for that particular passage (a fat synth line and dull kickdrum). I'm not concerned with the highs/lows, it's the distortion in the right channel I'm worried about...

The point about the way a record "sounds" indicates something about the cartridge and issues it could be having.This is very subjective and you must use your ears very critically listening for the small things.With a good table like a Rega P5 you should look for every clue.You should worry about alignment and not accept the Rega method as the last word.Many prefer a Baerwald aligment over Rega's as it gets better results with distortion.The sound and surface noise you hear will change with the cartridge model and alignment system you use.Records themselves must be cleaned even before their first play.The manufacturing process leaves debris in the grooves and surface of a record,which acts as missiles on the groove walls destroying a record, if the record has not been thoroughly deep groove cleaned first.If you are doing this(cleaning) and there is distortion,claim a refund or new copy.Many complain today about damaged new pressings from various companies.You could also have a damaged stylus which chews up records,do not play anything if ALL your records are distorting and get a professional to check your set-up.