I would agree with the thread point about the audible improvements being questionable.
BUT, I disagree that they are not important. The output of a moderately designed power supply is not perfect.To think that is idealist, and hopeful at best. These are adequate for the task at hand, I will grant, but not great.
There are several methods of providing this type of equipment, one of which is protection. Also to ensure that all components of your system are good quality.
As Alan states, this is one of those areas that manufacturers quickly vanish when challeneged to produce tangible results...just like the cable mfg'ers!!!!
Unless you are having power problems - which you should address with an electrician - put your money to other areas of your system
