Why does my headphone set up sound better ?

Dave, you are correct. I didn't understand the original question. In an A-B comparison, if the RCA output sounds better than the digital output->DAC, the fault may be in the DAC or the cabling. My systems always improved when I used a stand-alone DAC.

The Philips CD80 has a very good headphone output section. That, coupled with its now-classic 1541A DAC chipset, may account for the superior sound compared to your more complex hookup.

Thanks Davetherave,you are right, my question was related to the headphone output of the CD80 vs. the DAC and M-F X-CAN output to headphone . Should have been clearer about this. LOL, my room setup is far more realistic than the headphone sound from either output.
Nonetheless, I have AB'ed the CD80 headphone output vs.
the CD80 as transport to the EAD DAC to M-F X-Can at length.
There is less resolution from the DAC/CAN combo vs. the CD80 headphone output alone which is really surprising to me given the cost diff and of course the supposed superiority of the stand alone DAC and headphone amp. BTW, I am using Harmonic Tech Platinum digital connection between the transport and DAC and Cardas Hex Golden 5C interconnect between the DAC and the X-CAN. Could the extra cabling cause this?