How much is too much humming / buzzing? (Marantz Amp)

Hello all -
My Marantz PM-11S1 when on seems to have a noticeable hum/buzz , is this normal?

I checked the outlet and its definitely grounded . I actually moved some halogen lights to another outlet because it was adding some noise. So now I’m curious if something else in the chain could be causing hum . Its definitely coming from the amp not the speakers....thanks!