Open up an old desktop or dead laptop power supply. You will find inside an input line filter and an output filter, just like you want to buy. Open up your dac you will find lots of regulators and powersupply filtering, same with your amplifier. Many changes to your system may or may change the perceived sound better or worse.
A few years after I retired I took a part time job. There at work I met another fellow retired guy who also worked part time. Neither of us needed the money, just something to do. He told me a story of when he worked as a salesman in a high end stereo shop. The client wanted a super tweeter in addition to his multi $$$$$$ speakers. My buddy said sure no problem. My budy the salesman and a technician went to the clients home added the tweeters, new crossovers fancy cables etc. Before they did any measurements and setups they listened to some music. The client was amazed at the improved micro detail etc etc etc. The technician whispered to my buddy and said the tweeters arent hooked up yet.
