Some advice please guys
I currently stream my music to my Denon PMA-250SE & B&W DM601's from my Macbook Pro via my airport express, I'm use to CD quality and this sounds really flat with lack of detail, I know I need to buy a DAC but I'm on a budget, I'm not that fussed if I have to get rid of the Airport (although this is handy) as I have no issue connecting via USB, does streaming wireless cause lack of quality compared to USB, also which of the below would you suggest, baring in mind I could do with spending under £100 but if the DAC's in that range aren't upto the job then I'll have to save a bit extra (which I'd prefer not to do)
1. CYP AU-D150 £80
2. Arcam rDac £135
3. Beresford TC-7520 approx £140 (eBay)
I have looked at the Fiio E17 but I don't think that would improve my sound quality much, I've never actually heard a DAC so I don't know how much of an improve they will give me but everyone insists they are a must for playback via iTunes, I'm basically looking for something with more of a dynamic sound with punchy bass and clarity, I mainly listen to Hip Hop, Bob Marley, REM, etc.
Thanks in advance