Oh i see most work with multi voltage. Only thing thats off putting is the lack of binding posts. I'll try to find a used Woo WEE. I'm not exactly sure what Stax headphone to pick though. I love the sound signature of my HD600, So far im considering the Sr-l300 Sr-l500 or SR-507 but not quite sure what to go for.
I would like something with more bass than the HD600 the tonal balance of the HD600 is great just the bass rolloff lets it down for me.