Hey there, I recently got stationed in Germany and will be here for a few years. My old AVR is 110v and is already bulky enough, I don't feel like adding another clunky power transformer to the office setup. Onboard audio is not very good. Could someone please suggest a decent 100-240v headphone amplifier to buy, one that I can take back to the US with me after my time here is up? I am using AKG K712 Pro headphones and would like to spend no more than $500.