How can I tell if I need a better clock for my DAC?

Thanks, everyone, for your inputs.  Unfortunately, much of what was said went over my head.  Could someone recommend a good, readable reference on dacs?

I suspect a lot of new dacs sound better than your Cambridge but it doesn't have to do with just jitter.

Thanks for the additional references on dacs -- that's a good start!  As for the quoted comment, @headphonedreams may be right about that, but it leads to a more basic question.  By my standards, the Cambridge is a fairly expensive (and well-reviewed) unit, but the sound it gives to a Redbook CD doesn't compete with that of my more modest phono (Technics SL-D2 with a Nagoka MP-110).  Can I expect to get comparable sound quality with a CD player and DAC, without spending well over $1000, or is this the unavoidable result of the 44/16 format?

@melm — thanks for your advice. I tried ripping to hard drive, but could not hear any improvement. I may have to go with your higher cost option — mind sharing which DAC you bought?

@headphonedreams and @melm — thanks for your posts — it sounds like my CXU could benefit from a reclocker; now I need to decide if the new clock will make more noticeable improvement than a better CDP or DAC... or MCP decoder, or whatever. Will the audio solution ever make itself known?