There was a time, back in the day, when I could definitely tell the difference between the DAC in a basic CD player and a high-end external DAC. Those days ended a long time ago. The technology has been around so long that it is simply not expensive to make a decent DAC. It is damned near impossible to hear the difference between DACs these days.
Here's my take on stuff like DACs, speaker grills, horizontal MTM center channels and things of that nature. If you system is in your living room, set up where it best fits and operating without the benefit of acoustic treatments, most of the more subtle stuff is masked by room acoustics. I almost guaranty that room acoustics and less than perfect speaker placement have an enormous amount to do with the things that I don't hear.