Many devices are built with a transformer that has taps for 220 and 110V. In that case all you need is a service technician that opens the unit and changes the taps from 220 to 110, and you are ready to go. Check if your Marantz is made like this. I have had this done with Rotel, McIntosh, and know Bryston is the same. It cost me all of us$50 per unit. BTW, initially I was told by McIntosh I had to change the torroid in the amp...fortunately had a reliable service tech who said otherwise.
Let us know if this works.
Let us know if this works.