Neve is best known for their pro-audio recording studio equipment.
rupertneve.com/products/rnhp-headphone-amplifier/#tech-specs

A Headphone Amplifier that has been designed to drive well, all types of headphones out there, according to Darko Audio:
And sonically up with the best - for US$499.

" To put things succinctly: the RNHP is a clean, clear sounding amplifier with an excellent sense of drive. "

" It might just become your first – or last – headphone amplifier. "

DarkLantern blog - darklanternforowen.wordpress.com

A couple of things I like on a headphone amp, remote volume control which I have on the Oppo and balance switch which none of my remaining amps has. When one ear is occasionally playing up it'd be nice to be able to try for some sort of balance side to side.