do you have the manuals for each model of player? They should state what the output level is for a standard signal. Which input are you using on the Marantz? Does the Sony have a headphone jack, and do those selections sound clean on headphones plugged into the player? The only other thing you can do is put some sort of pad or attenuator between the Sony and the Marantz if the input level is just excessive to overload the preamp. You could build one dirt cheap if you knew how to do any electronic construction, would consist of maybe between 4 and 6 resistors arranged correctly and correct values. Or easier yet, a dual potentiometer in a box that you could just use to set the level till the Samsung and Sony levels sound the same? That would work after you prove the problem is overload of the receiver.
Help with distortion
I have a Marantz 4020 receiver. I have a Sony CD recorder and DVD player. On certain CD's--notably solo piano by Kenny Werner and Kenny Drew, Jr., which sound like they are recorded at very high levels, I get distortion that sounds like the input signal is too strong. With my cheap Samsung DVD player, they sound fine. What is wrong? What can I do?