[jtmccoy]

So I got my headphones.  They sound good with my AV receiver, but I keep reading about how they'll sound SO MUCH BETTER with a DAC/amp combo.  If I were to go the whole DAC/amp route (*sigh...and so it begins*), how exactly does that work? I see a lot of people recommending Fiio as a budget-friendly option, but it seems those are mostly for PCs and portable devices. I want to listen to music and watch movies through my Blu-ray and game through my Xbox. My Blu-ray just has an HDMI out and a coax out, the Xbox has HDMI and Toslink. Do they make DAC/amp combos that work with HDMI, and if so, how would I still get video? Or does the DAC/amp plug into my AV receiver?  Finally, do I need both a DAC and amp?
 
I have no idea what I'm doing.

 

[NA Blur]

If you are satisfied with how you gear sounds through the receiver there may not be any reason to "upgrade".  Your receiver most likely has a DAC in it and it surely has an amp built in.  Any device that plays digital media like a CD player, XBOX, etc all have DAC chips in them.

 

[PurpleAngel]

  So I got my headphones.  They sound good with my AV receiver, but I keep reading about how they'll sound SO MUCH BETTER with a DAC/amp combo.  If I were to go the whole DAC/amp route (*sigh...and so it begins*), how exactly does that work? I see a lot of people recommending Fiio as a budget-friendly option, but it seems those are mostly for PCs and portable devices. I want to listen to music and watch movies through my Blu-ray and game through my Xbox. My Blu-ray just has an HDMI out and a coax out, the Xbox has HDMI and Toslink. Do they make DAC/amp combos that work with HDMI, and if so, how would I still get video? Or does the DAC/amp plug into my AV receiver?  Finally, do I need both a DAC and amp?

Technically an external DAC & head amp might improve audio quality, but trying to integrate them "effectively" into your PC/Xbox/Denon setup would not really be worth it.
Best to just use HDMI cables for all the connections and plug the HD598s straight into the Denon receiver.
 
You could get a Creative Labs Sound Blaster Z sound card, $60-$90 and install it into the PC, and plug the HD598s into the SB-Z, which might help for the PC side.
But there is not a whole lot you can do for the Xbox side.