I have DC in my line which is causing a mechanical hum the transformer. This product did what it supposed to, do why isn’t available anymore. It was in an inexpensive solution to a common problem
Emotiva makes a similar product.
Does DC offset/bias manifest itself in anyway that is audible other than the hum or vibration of large torroids?
In other words, is there any reason to believe a DC filter would further improve things in the absense of a hum?