In my opinion, there is little doubt that the needs for power scrubbing is related to the power source in your area. It does vary from one area of the country to another. Urban areas are worst. If you live in a rural area and have few "dirty" users in your area, it is concievable that you may realize little or no improvement. Also, things depend on what you have in your house that may interject noise onto the line. If you have few, or no offending items, this would also lead to not hearing a difference.
While I generally maintain that differences in sound can be heard by most people, if an upgrade in power cord makes no difference to your ears, then IMO it is not a cost effective modification for you.
While I generally maintain that differences in sound can be heard by most people, if an upgrade in power cord makes no difference to your ears, then IMO it is not a cost effective modification for you.