Any respect for Manley? They are scheduled to show their "Absolute Headphone Amplifier" at RMAF. Looks slick, but not cheap at $3k-$4k (estimated). https://www.manley.com/hifi/mabhpa It has a way to vary negative feedback. I wonder if I'll be able to distinguish any difference. Guess I'll find out in less than a month. Anyone heard this amp? Head out on the back. Not a great design choice, IMHO.