I have no connection to Blue Circle. They just seem to make electronic products that "sound right" to me; and their accessories like cables and power products do what they claim. All for a reasonal price. I was never a believer in buying a system all from the same company, but Gilbert is slowly changing my mind on that. (In his case anyway)
The Noisehound is a parallel filter.
Since it is parallel, it removes the grunge without getting in the way of the power flow, which would limit dynamics. Many of the better power condition units on the market like Vansevers are also parallel.
There are some interviews with Gilbert Yeung (the founder) were he is asked why this or that amp or preamp does not lab test well (against the established benchmark or norm). His answer is always that he could have made it lab test better, but then it would not have sounded as good. Tells you something about the "established benchmark" (there may be a better way), and that Gilbert uses his ears, and thinks outside the box to design gear.