Eh, I tend to use pricier DAC combo/stack for my cans, I've tried my Denons on my Oppo HA-1 combo, as well as on my Gustard X12 + H10 stack and the Denons do sound quite lovely, no hiss, crackle or pop at all. I play music - DSD128, DSD64, WAV, FLAC and MP3 - thru Foobar2k. You can try Schiit DAC and amp stacks, read very good impressions and reviews about them. I've already sold my Schiit gear, but I used to have the first gen Lyr and Vali, the latter despite its diminutive size was able to handle my Beyerdynamic DT990 600 Ohms quite easily. Oh yeah, the Lyr did have an issue with noise floor I believe, with nothing playing, I did hear a soft hum (I'd to turn up volume a bit though, at the sane level I listen to, I don't hear the hum), either that, or my Lyr was faulty to begin with. 
Nice stuff that you have here! Why did you sell your Schiit stuff?
About the noise, it's pretty common with tubes, isn't it? I had the chance to test my D5K on some high-end tube amp at another audiophile place, and I really didn't like the sound (noise + too much treble). I'm not an expert though, but for now I'm only considering transistors.
You can also read up on the JDS Labs Objective2, though at that price level, I'd rather look at a Schiit Magni + Modi (Gen2? Uber?) stack. Just took note of your XPS 13 reference, so you wanna use the DAC at home? Or portability is a factor? Oh yeah, you can consider the iFi iDSD Nano, great portable unit that does FLAC/WAV/DSD/MP3 well enough, adds a little warmth to the sound. I guess you can read up on them and I'm sure there're literally dozens and dozens of others to choose from.
Yeah, everyone seems to advice the JDS o2, but for the price of the DAC+Amp combo, I'm not sure I want to order it without trying it before... and I doubt there's a single vendor in France. The Modi 2 + Magni 2 seems pretty good too, but might be a bit easier to try out somewhere, so I might go on that way.
I really like the fact that they both do support Linux officially, which doesn't seem that common for DACs.
Portability is half of a factor, in the sense that it's for work, and I don't really want to buy a 20 Kg amp, it must be small enough to be on my desktop.
I'm traveling with the laptop sometimes, but I think I'll rather take my Shure IEMs than my Denons, and the Intel cheapset will be good enough.
About the iFi iDSD Nano, this is the first time I hear about it. Going to take a look, but I'm not much into "warm" sounds, I prefer clean neutral and detailed sounds. Also, what to expect from a portable DAC? Is it really the same level of quality as a desktop DAC?
