Is it all in my head?

To update the thread, I can now hear a difference. Cd player with z dac sounds best, followed by streaming spotify with wadia 170 using z dac, followed by cd player using its own internal dac. Don't know if the dac opened up as it broke in or if now I can just hear a difference, or both, but I can definately tell a difference now...

My experience has been that no two pieces of gear sound exactly the same, but differences can run the scale from little or no or insignificant difference to major difference.

Usually the biggest differences can be attributed to major differences in design and approach between two units being compared.

Published specs may be useful but do not tell the whole story, even if accurate.

Test bench measures by an independent and unbiased source like those in mags like Stereophile for example, are more helpful for painting a better picture of what to expect, but still do not tell the whole story for that device much less overall performance of any system it is used in.

In the end, your ears are the ultimate test. Time and patience is needed in order to have any chance of sorting through it all in a meaningful fashion.

One of my favorite quotes as it relates to high end audio:

"A difference that makes no difference is no difference."

Subtle differences usually take some time to fully grasp. Don't believe the hype that the glossy rags spew, not every difference is jaw-dropping. Enjoy the music.