Could members who have heard both kindly provide some comparative comments on them? I wonder which one is overall superior, a used BA (with good 2a3 perhaps) or a new ZD Super? I am saving towards a purchase of a mid-level or above amp to drive primarily HD800s and 650s (even better if it can drive HE-6s to a somewhat decent level). I don't have experiences with decent tube amps except the entry-level LD MK3 with C3g drivers. My reference SS amp is Taurus MK2 and I like its precise imaging capability besides overall excellent performance. But it would be nice to have the options to get warmer/lusher mids and sweeter trebles with tube rolling. Thanks.