Originally Posted by PurpleAngel
Audio quality improvement will depend on your budget for a DAC/Amp.
I would say to just get the FiiO E10 for now, later on you could sell it off if you felt like upgrading.
I would guess the E10's DAC chip (WM8740) is at least a little better then the Mac's DAC chip.
Also the E10's amplifier has a very low output impedance, like 1-Ohm, which should help at least a little with audio quality, for 30-Ohm headphones, like the Philips.
I was going to get the E10 but there were 2 different owners who commented in the Fidelio X1 review section that it didn't sound great with them. Precisely that it sounded a bit muddy and dark.
From my research I read that the E17 has similar hardware to the E10 so that will probably also not be great with the Fidelio.
So if I'm going to buy a DAC/amp it'd probably only be worth getting something at a higher price range. Based on comments I've read and availability in the UK, the choices would then be the EHP O2D (£190), HRT Microstreamer (£180) or Audioquest Dragonfly (£170). A Fidelio X1 user did also mention that these headphones sounded good with the Denon PMA 720 E (£200).
So the options are basically between driving it through the Macbook pro or possibly getting one of the above (leaning toward the EHP O2D) but not sure it's worth spending close to 1.5 x the cost of the headphones on a DAC/amp, especially since I have no idea the extent of the likely improvements in sound quality if any.