My first inclination would be to suspect analog interference somewhere downstream of the DAC before the signal gets to your speakers. Digital media like CDs do not have the steady signal degredation of analog sources like vinyl LPs. If the problem were in the CD itself or the reading mechanism, you would experience audio drop-outs or skipping, jumping sound as opposed to static. Assuming that you don't want to muck around in the interior of your CD player, I would experiment with other speakers/headphones to rule out a problem with them. Also try gently cleaning any openings that may have been soiled by environmental contaminants. Simply blowing dust out of headphone jacks (or ideally using compressed air) might clear up some problems.