when using more resolving equipment. mp3 files are highly compressed and do not sound good on good equipment.

An amp would also require loudspeakers. What are you planning to do for those?

Are you listening to local radio stations over the air? If so, that will require a tuner or a receiver. If you are listening to radio over the internet, even "high-res" streams are at diminished resolution. It might not be worth getting good equipment if all it will do is make the deficiencies in your sources more evident.