Would someone explain what "up sampling" means and how it can affect the sound?

I completely agree with Gdhal that all available information should be considered. For example, as Mapman alluded to and as I have stated in a number of past threads, specifications can often be particularly useful in **ruling out** components from consideration that would be poor matches to the components they would be used with. Thereby reducing the randomness of the component selection process, and the likelihood of expensive mistakes.

Also, "trust your ears" only goes so far. For example, obviously it is often not possible to audition a component in one’s own room with one’s own equipment. And just as obviously listening to a component in a less familiar environment with less than familiar associated equipment, probably during a relatively brief audition, will not necessarily say very much about how that equipment will sound to that listener in his or her own room with his or her own associated equipment, over the long-term.

Of course, this assumes that one has sufficient knowledge about specs to not misapply them. For example, if everything else is equal I would expect an amplifier having 0.0001% total harmonic distortion to be very likely to sound worse than one having 1% total harmonic distortion, when used in conjunction with many or most speakers. Why? Because the 0.0001% amplifier was probably designed with specmanship rather than sonics as the leading priority, and the 0.0001% THD figure was probably accomplished via heavy-handed application of feedback, with the adverse side effects that often go with it.

On another note, kudos to Bombaywalla for his excellent post.

Regards,
-- Al

But what I am saying, and I'm sticking to it, at least for now, is that knowing about the mechanics of upsampling or what DAC chip is not going to matter one iota to whether you will like the player.  I know some people believe that each DAC chip has a sound, or that a ribbon tweeter is automatically brighter than a silk dome and so on.  In my experience, I have found those generalizations not to be true.

I agree with this, Chayro, at least as a rule of thumb that is true most of the time.  It follows from my belief (shared by many others, of course) that what usually matters most in the design of an audio component is not the approach that is chosen, but how well the chosen approach is implemented.

Regards,
-- Al