Modest(average) CD players are very sensitive to AC noise incoming and also output digital noise which is very audible.
The beauty of FM broadcast is that you don't have the digital electronics of a CD player creating the digital noise into your system; and, many quality broadcasters have some form of AC conditioning(balanced power)for their systems.
Your CD player will be far more listenable if you use isolation/conditioning on the AC feeding it and will improve further if you do the same for your preamp.
Best wishes for improved sound, there's a lot of great music on CD.
The beauty of FM broadcast is that you don't have the digital electronics of a CD player creating the digital noise into your system; and, many quality broadcasters have some form of AC conditioning(balanced power)for their systems.
Your CD player will be far more listenable if you use isolation/conditioning on the AC feeding it and will improve further if you do the same for your preamp.
Best wishes for improved sound, there's a lot of great music on CD.