The digital to analogue converter (s) selected play a big role, the more accurate and less prone to inaccuracies the better; Crystal Semiconductor and Texas Instruments (bought Burr Brown a while back) make some of the better known and respected DACs.
The quality of the transport makes a difference as well. The transport motor needs to be accurate (think of variations in speed on a turntable, same thing), stable so there aren't unnecessary and unwanted vibrations, and of course a good quality laser mechanism.
Like all electronic equipment the power supplies make a big difference, filtering out the grunge and providing a pure, clean voltage reference to the inards of the player. Some of the better CDP's have seperate power supplies for the digital and analogue sections of the player.
Finally, keeping airborne nasties out by extensive shielding teechniques is the hallmark of a good design. Goes without saying the quality of the various external parts impact the sound as well; the RCA and/or balanced jacks, power cord, etc....
Once you take all these things into account it's easy to see how CDP's vary in sound from one design to the next. Equally important to note turntable designers face some of the same challenges (obviously no DACs to deal with though). If you can, buy a top notch vinyl rig as a reference to compare how well various CD players sound in your setup.
The quality of the transport makes a difference as well. The transport motor needs to be accurate (think of variations in speed on a turntable, same thing), stable so there aren't unnecessary and unwanted vibrations, and of course a good quality laser mechanism.
Like all electronic equipment the power supplies make a big difference, filtering out the grunge and providing a pure, clean voltage reference to the inards of the player. Some of the better CDP's have seperate power supplies for the digital and analogue sections of the player.
Finally, keeping airborne nasties out by extensive shielding teechniques is the hallmark of a good design. Goes without saying the quality of the various external parts impact the sound as well; the RCA and/or balanced jacks, power cord, etc....
Once you take all these things into account it's easy to see how CDP's vary in sound from one design to the next. Equally important to note turntable designers face some of the same challenges (obviously no DACs to deal with though). If you can, buy a top notch vinyl rig as a reference to compare how well various CD players sound in your setup.