Oversampling vs upsampling


Can someone briefly explain the difference? Some CD players which have 24/192 DACS are listed as upsampling while other are not. Anyone know why? Thanks
rgcards
Thanks for a great explanation, Andy2! Now does the number of DAC chips used in the upsampling/anolog conversion have anything to do with sonic improvement. I know that Accuphase uses more I/C's in their higher pried models?

Statistically, I would think that it "smooths" out the signal at the output.
Having two dac is equivalent to summing the output level of the DAc, average them (like (a + b)/2), then send them out to the output. It's like taking the average of two signals.

Whenever you take the average of anything, you reduce the peak and dip of that things that you try to average.
It's like the average income of people who live in California and people who live in Nevada is more or less the same. But if you look at the income of each individual in each state, you would see a lot of "peak and dip".

The same applies for electrical signal when you try to average them.

I have a Cary 303/200 and it also uses 2 dac per channel.
The Cary 306 uses up to 4 dac per channel and I think that's why it sounds smoother than the 303.
Close. What happens when you sum the outputs of two devices is that the signals they have in common (the real data or music) is summed (x2) while the random signals (noise) is cancelled. This is because the real signals occur at the same time in the same phase while the noise on one DAC is likely to be slightly different from the noise on the other. When you sum, the noises cancel and the real data sums.

Result is improved SNR.
Check out the following URL for an excellent article on this subject.

www.audiophilesystems.com/dcs/upandover.htm

Cheers! JZ