Any jitter will have come from the original rip and is now part of the file, unable to be removed. Am I wrong?
From what I have read, yes, you would be wrong, in context. There is a great article on jitter in a recent Stereophile or TAS issue that discussed jitter. Jitter is only an issue outside the digital realm, bringing it from analog to digital (i.e. making the master) and bringing it from digital back to analog. (So you are right in the sense of the original (master) rip, not the subsequent though and it cannot be removed. This is partly why early CD's were bad, according to the article.)