I travel a lot and hate the fact that my system sits home while I have to spend long nights in hotel rooms without tunes. I've put together a transportable (Not really Portable) Stereo system to bring with me to pass the time. The sound reproduction is quite satisfying through the Sennheiser HD600's coupled with either the Porta Corda headphone amp, or the homebrew CMOY op amp headphone amp. The Sony Walkman D EJ721 has a line out/digital out for a real step up when optical link is processed through a used Audio Alchemy DDE3.0. The Sony/Amp/ Headphone system also works and sounds well when the line out function is used (without the DA converter). A pair of closed headphones like the Sony MDR V6's or the more exotic Etymotic ear channel headphones convert this system from transportable to portable and even suitable for airline listening. I put the system together for about $400 used. I'm much happier now that I can have an above average system any where I need to travel and the sound is superior to the midfi systems for the home.