Generally wise/unwise to mix metals in AC plugs?

Just got a pc with gold plated plugs on both ends and the effect is to soften and merge contours -- "voices" sound like they're coming through a soft cotton scrim. Used on my dac. It's great for the many lo-fi historical opera recordings I listen to, but not for most everything else. Gold seems to take an edge off and to accentuate note decay. I like that. But double- gold is for normal purposes too much of a good thing.

So... maybe replace the male end with copper? I wonder what gold and silver would do?

Elizabeth.. wow good point. It is amazing...