Hello. So I primarily do most of my listening on my computer (macbook) or ipod. I have a pair of Audio Technica ATH-ESW9 that I have been using for a few years now, and it's time to pair them with a good portable amp. I am not looking to spend a fortune, but I don't want something that will need to be upgraded in a year either. I also want to upgrade my ESW9's sometime in the near future as well, that should also be mentioned. I was thinking I could get a quality portable amp for around 200, possibly even less. I am just looking for good overall value and was looking for some good suggestions that would suit my needs/setup. I listen to a wide range of music, but mostly electronic/soundscapes/downtempo/ambient if that makes a difference. Thanks for your help!