Just having a dedicated line back to the box doesn’t guarantee much of anything. The only real way to have the line totally isolated is with a plug/receptacle that accommodates an Isolated ground tied to a separate bus bar within the panel and then to actual Earth. If your dedicated line shares a ground bus inside the breaker panel, then it has a chance to pickup the same noise as the rest of the lines.
Hearing other appliances in dedicated line
Hello
Recently I started hearing clicks through my speakers when I power off my tv or change speeds on my fan. My system has a dedicated 10 gauge line running from the circuit breaker panel. Never had anything like that happen before. No changes were made to the system. Any help would be greatly appreciated.