DAC question

Are there audible differences between similar dac's? For example which dac is considered better, the UltraAnalog 20 bit dac or the Burr brown 1702? I realize that parts quality and implementation are very important, but if everything was equal which one is considered better and could you actually hear the difference between these chips in a high end cd player?
who can tell? AFAIK, no dac/cdp manufacturer offers units with alternative chip sets. am i wrong? -cfb
CFB- I certainly don't know of any. However, I think Chord has a unit that allows the user to select between internal delta-sigma and multi-bit d/a conversion. I know. Not quite the question asked, but somewhat related. am i wrong? only the Chord website knows for sure!
I have been listening to different cd players with and without a DAC being involved for several years now. To me, all the differences I have heard are very slight. I am now buying components based on the color of lights they have. I can usually see distinct differences in color. To answer your qustion, I don't have a clue.