I'm an audioguru, but not one of those audiophile freaks who claim that expensive majic makes better sound.
I can't hear distortion less than about 0.1%, so newly invented circuits with 0.0006% distortion aren't any better for me, nor for anyone I know.
The OP275 has a Butler front end and performs the same as ICs without it.
I use cheap TL071 single, TL072 dual and TL074 quad opamps for all my audio circuits. They are cheap because they are made and sold by the millions. They have a FET input I need sometimes, fairly low noise, wide bandwidth and a typical distortion of only 0.003%. :lol: