Adding, slightly, to Steve's ( @williewonka ) excellent advice:
Try more than one...preferably a few...
Really the only true way to tell is to try one.
Dedicated power supply and upgraded power cable
I would appreciate your thoughts on whether it wll make sense to upgrade the power cord of the external power supplies of my preamp and streamer.
To be honest, I was skeptical about the added benefit of high end power cords (not cables in general), but recently upgraded those of my monoblocks and the improvement was far beyond any expectation.
Now with the preamp and the streamer I am wondering wether their high end external power supplies will not diminish the potential improvement of such an upgrade.