I've spent a lot of time tuning a desktop and laptop for hifi audio. They run Gentoo Linux, mpd direct to hw(0,0), real-time tweaks, a Wavelength Proton USB DAC, and Wireworld Starlight USB cable. I've been at it for years. I'm on the road so I'm using the laptop (Dell XPS 13) and a powered FOXL portable with a Nordost iKable.
The other day I decided to try a Sansa Clip+ with Rockbox into the speaker instead of the DAC and I was amazed. It sounds better than my entire computer/DAC setup. I even unplugged the laptop from the wall and from all other USB devices and disabled all but one CPU core. The DAC is a little punchier but the highs are so much cleaner and more pure sounding from the Sansa. It's a lot less fatiguing and overall I greatly prefer the sound from the Sansa. I'd like to do this comparison on a real system but I'll be on the road for a long time.
I think the advantage the Sansa has is that it's an isolated, simple little device that doesn't generate so much EMI to pollute the sound, plus it has a much shorter signal path with no USB cable. I'm thinking of trying the Sony PCM-M10 in place of it since I need a recorder for needledrops anyway, and that should be even better. It's also worth mentioning that I have the FOXL, DAC, and Sansa on little plywood platforms with Herbie's Baby Booties underneath.
What do you make of this? Am I using the wrong DAC? With the Sansa sounding so much better than my computer/DAC, I'm tempted to call BS on the entire music server thing and go with DAP units from here on out.