The disc I have suggests that there is a build-up of residual magnetism within cables, circuit boards and copper wiring. That magnetism may also be present in spades, other connectors or solder for that matter; who knows? Sam Tellig, in a review of the Densen disc, suggested that excellent results were obtained with single ended tube gear, possibly as a result of demagnetizing the transformers. I don't know how it works and I don't really care. There will be a thousand engineers tell me that a power cord can't make a difference and I know that to be false. The fact is that the sweep tone tends to "clean things up" for lack of a better description. It is particularly noticeable, as Ljij suggests above, when it has not been used for some time. The effects are more subtle when using the sweep tone regularly (the disc I have suggests after every 30 hours of play-I use it about once a week), but they are indeed there. I don't need an engineer for that, and at $20 or so, this is not an outrageously expensive tweak. If it doesn't work for you, you're out $20. Bob Bundus alluded to this in a tweak thread a couple of weeks ago: if you don't have experience with something, why ridicule it? Obviously, from the way this thread has moved on, it is working for some people.