Just a suggestion. When soldering to the already used ground lugs on the RCA jacks, first remove enough solder to see the hole in the lug. Put the resistor lead through the hole, crimp, then solder. Otherwise you are using solder to "chewing gum" the resistor lead to the lug. Or, you could wrap the resistor lead around the bare wire that is already soldered to the lug, crimp, then solder.
Admittedly, the chewing gum thing is what we must do with most of the power switches, but it is a bad practice and unreliable.