I am looking for IEM with emotional vocals. I don't know if the term is correct, what I'm looking for is which give goosebumps in certain vocal, for instance Matt Cradle, First Time Ever I Saw Your Face in X Factor, or Adele - Someone like you live at Royal Albert Hall. Something that gives you...

Currently I have Fiio E6 amp. I tried to use it with recently bought K612. But it does not produce enough volume to my liking. I use a PC and on-board audio isn't the greatest. So I want recommendation on amp(+ dac is advantage) which could drive K612 well. Current choices are SMSL M2 or Fiio...