I'm sitting here listening to apple lossless files from an iMac on a new pair of Sure SRH840s coming through USB on a Centrance Dacport. My first impression is WOW! Audiophile terms are a lot like wine tasting terms but the ones that comes to mind here are lush, warm and tight. This is a very good combo especially on Lou Reed's Walk On The Wild Side - the colored girls really do go "Doo do doo, doo do doo, doo do doo" and you can savor every bit of vocal detail. There's nice bass and a pleasing energy that is definitely not boring. The sax solo at the end can sound harsh on some headphones but it is silky smooth with this combo. Marc Cohn's Walking In Memphis (Gold Mofi remastered CD) is also an amazing experience along with Marc Broussard's Save Our Soul cover album. Bruce Springsteen's Devil's and Dust and Dave Matthews acoustic version of Grave Digger both have great guitar work and haunting vocals that really shine on the SRH840/Dacport. About the only thing that didn't sound fantastic so far was Dusty by Kings of Leon. It sounded a bit harsh in the highs/treble area. I'll go back to that song after some burn in to see if it smooths out.
The SRH840s sound pretty good out of my iPad playing lossless files but it definitely has more overhead and depth when used with an amp. Without an amp I was able to turn the volume all the way up and it was just a bit louder than I would normally choose so if you like to listen really loudly than you will find yourself on max volume.
I've read reviews where people talk about the 840s being plasticky and bass anemic which really proves that we all have different ears and different tastes. Im definitely not a bass head (my other cans are AKG 701's) but to my ears bass has a good presence, clarity and impact even when listening to NIN (had to turn up the Dacport to almost full volume for NIN). I ordered AKG K550s looking for a similar sound but they were delayed by a week so I picked up the Sure's while I was waiting (I get a store discount on a limited selection of closed cans at work). I can't wait to hear the K550's and to do a comparison. The winner will stay with me and the other ones will probably go to my wife. I suspect that neither of us will feel like the loser.