Hi, I have just inherited a Marantz pm35 mk2. It's rated at 45w per channel at 8ohm (55w at 4ohm) and thought I'd give it a run through my Zensor 5 speakers in case it's better than my similar period Denon 720. However the speakers are rated at 6ohm impedance. Is it 'safe' to run the Marantz...