I have no complaint about the fan at all, in mine. I've never noticed it. But, also haven't specifically listened for it either. The amp sits about 5 feet from where people are in the room, in direct line of sight.
I powered up the NX1000D and was SHOCKED at the jet fighter afterburner sound of the fan in that thing. I should have measured the dBs! I replaced the fan with something that is almost silent.