Since I've played some mp3s in the new quicktime player some won't work in macamp... playing a loud scratch sound... I've tried changing the file type/creators to macamp compatible ones... but to no avail.

anyone?

Haven't tried it this way yet, so far my comparing the two has been with separate copies of the files for each ...
Best bet I think would be get a copy of
MusicVac and use it to "clean up" the files
(if your lucky, something in one of MusicVac's log files might actually tell you something)