Got it last July and it gave a constant 'buzz' through my speakers (noticeable from about 15ft away at the listening position), after months of being told it was a grounding loop, which I knew was not the case (I tried it in three other peoples systems apart from my own-all of us are scrupulous about our mains supply), I gave it to an engineer.
When he told me he had screwed with the bias without a manual, I just dumped it in my garage.
Pass recommended an engineer at the other end of the u.k.who has 'almost' fixed it (at my expense).
He recommended replacing the op-amps which had been revised since my amp but had to take advice from Pass re the 'buzz'
It still gives a very slight buzz and I am told it is a problem with very long grounding tracks on the circuit board for the phono inputs - this can be tuned out.
Shame Pass could not have done this six months ago and saved me a lot of money and grief.
I'd love to say alls well that ends well but I'm singularly unimpressed by it. It does all the power, dynamics but subtlety, read ambience, harmonics etc don't seem to figure.
Tonally 'Bleached' would be my summation.
My Nu-Vista leaves it for dead with regard to creating something that sounds like real music.