Massive sudden hum - frightening!

That’s good news. It can be used permanently with no issues. I would get a decent mains plug where you can ensure the cable clamp mechanism (either a jaw type or the two screw clamp type can be used) so the wire can’t get pulled away from the earth terminal in the plug.

If you don’t want to use a mains plug then this type of earth bonding plug from an Antistatic kit (with no resistor) will do the job too. You’ll just need a 10mm female stud to connect it. It’s the safest option as the L & N pins are plastic.

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@james_n thank you for your help, it’s really appreciated.

I think I will make up a decent earth cable with a high quality mains & RCA plug.

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This type of plug is what I would recommend because there’s absolutely no chance of any accidental live connection, for example of the wire gets pulled and separates from the earth but then manages to touch the live terminal.

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Agreed. The other way is potting the internals of a standard plug to be completely sure of no accidental contact if pulled and the strain relief fails, but the bonding plug is the safest approach with no live pin.

I’m struggling to find an earth bonding plug with a binding post/banana jack without a resistor. Any guidance please?

As a temporary measure, can I just remove the L&N prongs from my plug?

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Try here Rico


And yes you could pull the L&N pins if they will come out. Good thinking.

Thanks James, i’m trying to avoid the versions with a snap connector, purely because I don’t want to buy a minimum quantity of 100 snaps!

Pulling the live and neutral pins is maybe not a good idea - it’s then possible to put the plug in upside down, which will open the shutters and expose live and neutral in the socket.

It’s also possible to twist the plug body, which could easily crack either the plug or socket.

If the issue with a conventional plug is the cable grip, some insulation tape wrapped round the wire might make it more secure - but I guess ideally find a plug with a grip that works!

Good point Andy about an inverted plug and shutters. Certainly the Earth bonding plug is going to be the safest approach for a permanent installation.

You could also perhaps squirt some hot glue or silicon sealant around the Live and Neutral terminals

I’d not get too worried about it. If the cable clamp works, it’s probably no less safe than a normally (three) wired plug. And in a hifi installation, the probability of it getting pulled has to be pretty low.

Yeah, I am inclined to agree. It will be a ‘set and forget’ solution I think. Thank you all for your very helpful advice.

leave the earth & neutral?

That would also work…

I guess the final note should be ‘if you’re not sure, dont’!

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As a wrap up to the persistent low volume hum, since changing my phono pre from a Phono Box to a Schiit Mani, the hum has disappeared when I remove my makeshift earth bond.

Seems the Phono Box was the culprit all along.


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