Hey frenchbat, this is exactly the sort of information I am looking for, so thank you for pointing it out!   Worst case scenario I have to try these things myself and see which one I like best...  

Thanks for the recommendations guys, wasn't familiar with them so I've looked them up.  My favourite so far is the Icon uDAC-2, seems to have good quality reviews, a higher bitrate across USB (24/96) and isn't "wasting" money on an amp circuit I won't use :)  Happy to hear more opinions though...

Hi, thanks for the reply.  I presume you mean the Icon u-DAC, not the DAC-9 as that's about £1000!?  I've not seen NuForce ones before so investigating their product range :)  

Hi all,   I've recently upgraded my headphones - my old setup was a pair of Sennheiser HD580s and a Total Bithead amp, had them for about 11 and 7 years respectively!  I purchased some AKG K702s and am happy with them, though I'm finding the bass isn't as responsive, and the Bithead is...