The better ones do a good job of filtering out common mode noise from electrical and magnetic fields and also filter noise from equipment (digital) to the outside. But not surprising, some of the cheaper ones can do as good of a job, if not better, than some of the more obscenely expensive ones.
...and I absolutely agree that the power supply design is everything, where a well shielded power cord compliments it rather than trying to wrestle it into submission.
...and I absolutely agree that the power supply design is everything, where a well shielded power cord compliments it rather than trying to wrestle it into submission.