Not what I wanted to hear at all...
But yes, browsing further online seem to point to bad capacitors, a known fact with NAD apparently... I've read 250$ for repairs!!!
I won't spent 250$ on a 8 years old amp that I paid 400$ back then...
What happened to the good ol'days when stuff lasted 30 years?!?
I would ditch the bastard in a heartbeat If could afford something new but alas... I am dirt poor!
Humming galore, here I come!
Thanks to all for the help!