I think you got bad advice. It is very common to get hum from a phono section with a ground loop, missing ground, bad connection, etc. That section has very high gain compared to the other inputs so unless things are just right it will hum. Even leaving them with no input can cause hum.
The first thing to do is insert shorting plugs into the phono inputs. If hum goes away it is external. If it still hums your NAD has a problem.
Need shorting plugs? Go to Radio Shack and buy some cheap phono plugs and somehow connect the two lugs (solder together, short with piece of bare wire, etc.)
The first thing to do is insert shorting plugs into the phono inputs. If hum goes away it is external. If it still hums your NAD has a problem.
Need shorting plugs? Go to Radio Shack and buy some cheap phono plugs and somehow connect the two lugs (solder together, short with piece of bare wire, etc.)