If you have an european or a japanese version of the Samsung Plasma TV, you MUST have a PERITEL (scart), this allow you to use the RGB output directly on it,
but if you have a US version ... you should think of change of country or try to install with a professionnal an european scart module ($30/$50).
It's an easy and common mod, just changing the IN/OUT card in the TV, and set it "ON" by the "Service Menu".
Then you will have the best for your Amiga !