More suggestion to diagnosing/fixing earth hum

[Sam Spoons]

I’m away from home now but just removed a couple of socket screws from my partners surface mount utility room sockets. They’re both Mk and have a small brass insert in the screw holes linked to the earth - I thought that was a standard?

The only ones I have which don't have the screws earthed are similar to these https://www.screwfix.com/p/british-gene ... pack/455xf

[Hugh Robjohns]

I have come across installations with metal back boxes where the earth wires from the cable aren't linked to the box at all, just the front sockets. In most cases the retaining front plate screws still pick up the earth as they pass through the holes, but not always.

[Sam Spoons]

Actually, now I think about it, all the sockets have earthed eyelets in the screw holes anyway

I must have fitted dozens over the years and when I saw that those plastic back boxes didn't have any earth connections I never made the connection (pun intended) between the two and assumed the screws would be unconnected too...

[Dave71]

Update. Swapped the socket out for a new one with the earthed screw holes and tried Hugh’s original suggestion of providing an earth to my signal chain - no joy. Ran an extension upstairs from a socket closest to my consumer unit to rule out a weak earth link in the ring main.
Still requires me to touch something to stop the buzz.

Borrowed another guitar (usa strat) expecting the single coils to be just as bad but found this to be significantly better.

Going to see which appears to be the worst guitar and experiment with cavity shielding.

[Hugh Robjohns]

Hurrah!