It is not normal. My first thought was that you had not grounded your turntable. That seems to have been corrected or at least not been the problem. Unless of course there was a problem with the Moscode Minuet and the results just sounded the same. Unlikely but not impossible.
Try grounding the Luxman to something metal. Next check and see if the RCA jacks are as they should be. If one is very loose or not quite well connected, that could be the problem.
Try grounding the Luxman to something metal. Next check and see if the RCA jacks are as they should be. If one is very loose or not quite well connected, that could be the problem.