Have recently got an Epiphany Acoustics O2 amp, some improvement but looking to upgrade from my Goldring DR150s next as these are apparently low resistance and easy to drive. Have been recommended Sennheiser and Beyerdynamic by guys at Epiphany. Wondering how people have demoed a number of phones to come to their decisions? Would it be best to just buy half a dozen, having agreed with retailer beforehand that the favourite would be kept and the rest returned? Or is this asking too much of a shop? <!--break-->I really would love to demo as many brands as possible, I'm looking to spend up to £300 to get the best from my Epiphany amp. Any experiences of this would be great please. (As an aside, still have a nagging doubt that I should have got the Epiphany amp with DAC, source is ipod touch or Marantz CD6004. Opinions please?). Thank you.