Many apologies, I tried to shirk the usual reviewer responsibilities with a carefully chosen thread title. I did forget to mention the headphones used, but as it happens I didn't write my review until I had tried all combinations of my available "quality" equipment. Namely, the HD600s+Cardas and Ety ER-4S with and without my 4.5V TAH, with three different mini-mini cables (Plastics, old red Straightwire, and Kimber). The conclusions were always the same, and so I decided against the Xtra.
I will have another thread soon about my experiences with the Zen 2.0 on my speaker system. It was depressing to say the least, having magnified all the faults I could hear through headphones and, at the time, found tolerable. I imagine the Xtra would have only aggravated this impression, although as I mentioned I no longer have the Xtra in my possession.
Hope that helps.
