Improve the sound of my CD Player?

here are some CDP tweaks that are very worthwhile...

Upgrade AC cord:
(& not all cords sound alike - I'm using a "relatively inexpensive" JPS Digital AC at the moment, but have tried many others - system synergy & your sonic preferences deterimine the best choice).

Coupling, Isolation & Shelving:
Coupling--
I have my CDP up on Nordost Pulsar Points (in titanium option - didn't try the cheaper aluminum's) but I have also tried many others such as carbon fiber Black Diamond #3's & #4's, brass Audio Points & pucks, ceramic DH Labs, & titanium Orchard Bay cones with brass pucks. Every cone has a different sonic signature & again, system synergy & your sonic preferences deterimine the best choice. Varying the spacing between cones changes tonality - further apart = brighter / more detailed, & closer together = warmer / less detailed.
Shelving--
Presently the cones/pucks sit atop a Zoethecus Z-Slab shelf, which is my dead-mass for absorbing the microvibrations coupled into it via the cones. Black Diamond shelves also work very well but have a slightly different sonic signature. Again, system synergy & your sonic preferences deterimine the best choice of shelf.
Isolation--
In order to isolate the dead-mass shelf from the rack's vibrations, I have the self siting atop a set of Vibrapods (model #'s chosen for the total weight of the "stack").

Interconnects: some people tune their rigs by changing interconnects - even the choice of digital cable has been reported to have profound effects, in addition to the analog cables. I chose my cables for neutrality & do my tuning as-above, but others chose to do it via their cabling as well.

Ljgj--have you used the Taddeo unit you mentioned?? I've been tempted to get one, but wonder if it really does anything. Thanks

I do use one and I sometimes felt like it wasn't adding a night and day difference until I took it out then I would say something is not as good as when it was in. It does a smoother job IMO than the triphazers I tried. Of course I only used the 4.0 model on that.

Ljgj...thanks for your answer...one more question.. do you know what the difference is between the $99 taddeo on their web page and the $49 Acoustic Research "TDS" device for sale at audio advisor?

I went to the Audio Advisor site and did not see any device by Audio Research of a similar nature. If you are referring to the TDS unit that changes the harmonics and comes in two versions - I am familiar with the TDS Audiophile version. I owned one. It does give you a definite night and day difference in sound but not all for the better in my opinion. It also introduces noise into the system by boosting various frequency levels to bring forward a brighter and more forward sound that I am sure some people may like. I did not.