My knowledge on this stuff is pish, so I’m hoping at least one of you will have an answer…
My sister had been complaining about a noise with her kit and thought it was either the amp or TT. Being a good brother I took another amp and TT. After some swapping of kit I came to the conclusion that it’s a mains issue - same hum / noise through the speakers. As I have no idea can anyone suggest a solution or anything else that can be done to sort it?
Cheers
Earthing?
I don’t know anything either.
Cam belt or alternator imo
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For clean mains you need a Coco-san power plant
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Is it an old house?
Does the hum go up and down with volume control?
Dunno. It’s a RX7 
70s abode. Honestly can’t remember if the noise increased. I’ll ask her to try tomorrow.
Was it on separate sockets or through a mains block gubbins?
Is it as bad with a cd?
If you switch it off and stand in the street does it decrease?
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Swapped blocks. Swapped wall sockets. Same with CDs. Didn’t try the street thing.
5g innit.
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The router is in the same room
A normal router won’t do 50Hz hum.
Thanks. At least that’s one decent answer 
So, I’m still no closer to a solution
No one wants to help because the internet police will jump on them for health and safety!
Have read up on earth loops?
Did you report if it was volume related? I.e louder with volume.
I bet lifting the earth on the amp or turntable will remove the problem.
Of course this is not a solution, unless you like electrocution - if there’s a failure internally like a live mains feed gets to touch the metal amp case. You get the jolt if you touch the case instead of it going to earth.
Continental double insulated gear doesn’t have an earth. It’s built so that a failure like the above doesn’t get to the end user.
In living rooms etc it’s just 2 pole, live and neutral, only earthed in water supply rooms, kitchen, bathrooms etc.
That caused my UK Marshall guitar amp all sorts of problems back when I lived in Sweden.
I earthed it to the radiator 
got rid of the hum:)
You can get plugins that essentially lift the earth but do it via electronics. I believe these are safe (disclaimer applies).
Never used one myself.
Things you can do;
Have you tried different extension blocks.
Try plugging the turntable and or amp etc into a different socket (done) even a different room on an extension lead. Try from the kitchen, utility room near the fuse box, garage wherever…
This is safe to do.
Does exactly the same kit hum when installed in your house?
An electrician can do a full check for you of course. They can check the continuity of earth, leakage voltage etc etc.
They do it and charge for each fused circuit. Gets expense on larger houses.
We live in a thatched cottage and this is an insurance requirement every 5 years!
You might just have a dodgy socket or earth cabling at the socket or supply end is loose.
That would need fixing of course.
So, explore or have someone explore your earths and report back.
Thanks Steve. We tried pretty much everything you suggest above. I’ll look into the plug in idea and see if that helps
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Have you tried moving the system to a different room to see if it happens there? Could be an earth issue with the wall socket.
Didn’t move the kit but ran an extension lead to another room. Same result 
If your kit worked fine at your home and didn’t at your sisters it would suggest an issue within the house to me. Maybe she should get an electrician to check the house wiring.
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I had a weird noise that came and went on the mains when I moved in our current house. Borrowed conditioners/regenerators, asked lots of folks…
Had Western Power in measured for a week-graphs etc no useful answers from anywhere…
Long story short I noticed that the times of the noise altered, and eventually realised this was connected to day light, I then noticed a streetlamp was malfunctioning (guess faulty PIR sensor) and WP reported to the LA to fix.
The minute they did noise problem was solved…
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