Originally Posted by hrbballman
wondering if you can plug the Zune USB chord directly into the USB port on the DAC/headphone amp.
Not unless the DAC/headphone amp specifically says you can. Doubt there is something out there that does that. The port at the bottom is there to transfer the digital bits to/from a PC. It is not even normally intended to send those bits from the Zune, to the PC to be played. they are transfered there to be stored until the PC audio parts can play them from the file (not from the Zune). The DAC part of the DAC/headphone amp would have to act like a USB host to the Zune, snag the files, and convert them to analog and pass them to the amp part of the DAC/headphone amp to pass to the headphones.
While I expect you can find a DAC/headphone amp that plays files from USB drives, just as you can find car stereos that play from a USB drive, the Zune is not seen as a drive, so that capability doesn't work when attaching a Zune, via USB.
I do have things that dock the Zune, and play, but they are getting analog from the dock connector, already processed by the Zune's DAC. It does sound better than plugging into the headphone jack, a little, to me, but that is the quality of the amp after the internal DAC. Kind of like line out from a receiver sounds better depending on the amp it is fed into.
I can talk about this from the purely technical point of view, but I would never call myself an audiophile, because I can't hear the difference between 256bit audio and 384bit audio. I know people who can, or say they can. I can hear the difference between my Zune, and music from a record played on a tube amplifier, and the reality is, which one is 'better' depends on what you like....unless you're an audiophile. Then other audiophiles will tell you which one is 'better'. You ought to try just plugging those Sennheisers into a Zune directly. I've had Sennheisers, back in the 70's, and they were amazing back then. You could hear the hiss of the tape heads and the dust specks on the albums. I have Bose now. Sounds great to me, and after all, that's who I am trying to please.
Just my 2 cents, and probably not worth that.