So how can Denon have proper engineering in all aspects and then not do the mat right? Seem to be contradicting yourself here.
Where you’ve been in the 70’s ? Look at the cables, speaker terminals whatever when you got vintage equipment.. Over 40 years it wasn’t so important, rubber mat was a standard mat by default from many manufacturers including top Denon, Victor and Technics. Stock feet under those plinth for Denon, Victor, Technics is garbage. But even in the 70’s some manufacturers made separate mats, feet etc or upgrade for those who willing to spend more. DP-80 platter is has its unique structure, you can search audiogon, heavy mats are not recommended for this particular platter structure.