I told this guy he was in a crisis state. Don't worry about audio. Not only is the socket dumping water on the bus, the mast is held in place with a single 2 hole strap with screws into plastic anchors. The mast is the support for the drop. There is a lot of load on it....and you know the connections and terminals in that meter are an abomination too. Sobering pics for audio folks with expensive systems, cables and "ground boxes."
Add to that he has an aerial 100A feeder to a garage that was run with THHN. The casing is rotting away and hanging to about 7 feet above ground.
His MBL system is fed by a 15A romex. At least he has his front end in another room and it ended up on a separate branch from the amps. When the service is changed, I will spec 10 AWG dedicated circuits.