High-frequency squeak in power supplies, how to remove?

Question

Power Supply

In general, I brought the computer to a private house in the village. The wiring is old, there are two wires to each outlet, the shield hangs on the street on a pole. When connected to a power outlet, the power supply starts beeping, not very loudly, but this squeak just outputs. This squeak gives off to the speakers, headphones and decreases if you touch the case. The same thing, if you put the phone on charge and connect the headphones, the squeak is also worth it. It's the same with a laptop, when the charger is connected, a squeak appears in the headphones, and if you touch the USB port, then the squeak is less. Can something be done about it?

Answer 1

Buy a high-quality power supply that does not save on filters

Answer 2

Make grounding in the socket

Answer 3

High-frequency squeak is a choke or transformer