It could be either a bad calibration of the needle, or a bad connection to your PC.  I assume it's all tracks rather than just a few?

 

I did this recently -- archive all KLF vinyl to CD -- and everything was of equal volume.  As an example of a wavform from a badly calibrated record player, rip some of the tracks off Ultra Rare Tracks (AYNIL is one, IIRC).

 

-paul