Do power supply units/cables make a difference in sound quality?

Indeed. That is my conclusion.  I will invest in a new cartridge for my turntable.  I think the Koetsu has worn down.  That will make a hearable difference playing records. Thanks all who took the time and trouble to answer my question.

@baumwoll For nearly 25+ years, I never felt the need to change power cords, fuses, interconnects, add power conditioners to "improve" the sound from my audio system. @jasonbourne52 pretty much summarized the technical reasons behind why such changes don't make a difference.

Electronic components have built-in power supplies that controls the DC voltage/current ultimately responsible for driving electronic components in the audio path. Some components have multiple power supplies with well regulated for fluctuations in the AC supply. This is not rocket science anymore, but well established design concepts of audio gear.  Adding power conditioners, changing power cords/fuses won't make an iota of a difference. Same goes with cables and interconnect where most commercially available at "reasonable prices" can get the job done. I have Kimber 8TC as speaker cables. All the components are plugged into surge protectors with power amp having its very own. So don't fall for marketing gimmicks and save your money

pwerahera I have the same view as you express in your post.  I wanted to see if anyone on this forum could give me convincing argument to change my mind.  The cost of these power control units and cables is far to high for the benefit the purport to deliver.  Good quality surge protectors and a stable source of AC is all I need on that end.

To a degree depends how revealing your system is.

@baumwoll Vast majority have never taken classes in electrical engineering that include Electrical Circuit Theory, Electrical Measurements, or Wiring Diagrams classes. Few years ago, one of the biomedical engineering faculty members told me, there is no need to teach sophomores Thevenin's and Norton's theorems because they are never going to need it. I can see in near future use of geometry, trigonometry, algebra getting the same treatment.  It is all now in the computer. You give the input parameters and computer gives you "what it thinks you want." But they lack the knowledge how to get there. So there you have it. For an old hack like me who spent hours and hours learning and then teaching these subjects face an uphill task convincing the masses what is true and what is not.

Glad you found some of us still around. One of my teachers/mentors passed away few years ago, Dr. Aram Budak who wrote several text books in EE. He would have gotten a good chuckle if he saw some of these posts describing audible differences in cables, fuses, etc. He retired to Grand Tetons, WY of all places. Until his very last breath, he could get a great view of the Tetons from his living room. He loved music and his favorite was Richard Strauss. His final request to the family was to play Death and Transfiguration at his funeral.