I recently set up my Marantz M-CR603 cd receiver. While changing a cd i touched the corner of the unit and felt a slight vibration from the unit.It felt like the vibration you would get from a transformer. As i am not too technically minded i went back to the store where i bought it. Their showroom model did the same and they had no explanation for it. I rang Marantz Technical Support who advised me to pull out the mains lead from unit and replace it the opposite way round. Made no difference. Set up unit away from TV and with another set of speakers, still the same. Any ideas if there is a problem or is this normal with this unit?