verifonixThe A90 is has a few obvious advantages but you say even on low impedence/sensitivity headphones through the single ended the A90 still sounds better? How much so if so?
AlltheheadphonesA90 just sounded best to me I can't explain it, I think it has different gain settings and higher maximum output, also balanced input. On paper it is a lot better, audibly maybe it was placebo but it's a great amp