The original wa3 was my first dedicated headphone amp. It was a work of art and built like a tank, but frankly even with the best tubes out there (the guy I picked it up from way back when threw in a pair of 7308 PQ's and a 5998), it is a slow high impedance amp, with a big stage, that just doesn't let hd800's full detail or speed shine through. I sold mine shortly after buying my hd800's and then building a bottlehead crack 9 or so years ago. Even stock, the crack is a far better match for hd800's as OTL's go (although a better match for hd650's), and it scales up with mods - plus building it is super fun and will get you started on diy! All that said, Purr1n's OP is dead on as usual that tube amps with output transformers are where it is at, especially for hd800's, with the exception of getting your hands on a Zana. I liked the wa6se a lot when I heard it with hd800's, and I would be very surprised if you didn't find it to be a big leap forward.