most of the flaws in vinyl and cd recordings are often emphasised by poor design, and a good amp will soften the effects, making them much more easily lived with.
A good amp won't do anything but amplify the source signal - a bad amp might emphasize the problems but a good amp certainly won't soften them.
I still have my original Denon CD player
which one? a couple of mates had one of the popular Denons and they sounded OK though their mid-fi amps, but in reality it sounded horribly metallic and hard.