Welcome ibis99,
Well, the Total Arihead and Bithead are both right in your price range. I use the Total Airhead with my SE530s and am impressed by the results. The amp brings out those last little bits of detail and tames the bass response from a muddy splat to the note you know it is. Combine this with Headrooms gigabag and a interconnect and your good to go. I also find with something as revealing as the 530s or my E4Cs, that lossless bit rates will be easily differentiated from lower 128,256, or even 320 kbps. The biggest difference I have heard with this amp however was with a pair of Grado SR80s and the Shure 110-220. The lower end shure 110s, which to my ears are, well, yucky, suddenly become listenable and take on a fair ammount of detail. Do some more research on your own, as there are a lot of amps in this price range, but just remember Headrooms 30 day money back policy, makes trying a product and finding what you like easy. Plus this is the best place to find people who love to help you find what you like because its their passion as well.
Kevin