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Humm from all in one stereo, double earthed!


Standard Member

I've read loads of replies about isolating earth loops on seperates etc, but nothing quite like my situation, so hopefully someone can help!

We have a little 'all in one' system that plays tape, cd, and radio with seperate speakers. you can only plug the speakers and aerial into it. Since we redecorated the bedroom (which included adding a couple of new electrical sockets) we put the radio back into the room and it constantly hums. I'm pretty sure this is a power supply related hum as it still does it on standby even if you disconnect the speakers (so it's not coming out of the speakers).

Co incidentally, we bought a small mono DAB a few months ago which is plugged in in the kitchen. this one has always buzzed/hummed really loudly all the time, again whether on standby or actually on. And it did this before any electical work was carried out in the bedroom.

both these items are double insulated, so I can't see how an earth fault could be the problem? Or how to solve it.
Is it possible our house electrics need some additional earth bonding or something (quite an old house)? Or are both of these radios just not working right?

any suggestions gratefully recieved, as the humming is driving us mad!:lease:


Distinguished Member
Before we go further, does the hum disappear if you unplug the aerial (applies to both humming devices)?

If it's the transformer, as seems likely for the all-in-one, only a service can resolve the problem.


Standard Member
hi, thanks for replying :)

I tried unplugging the aerial as well as the speakers, it's still humming/buzzing.
i also tried plugging it in in other rooms, still has the same noise.

on the other DAB radio, it has an integral aerial & speakers, so i can't un plug anything from that.

i do have another stereo plugged in in another bedroom, this is a bigger set up. It does not hum or buzz.

So i am coming to the conclusion that the small all in one and the dab must both have a fault. does this sound right?

thanks for all help!


Distinguished Member
The all-in-one does appear to have a fault.

For the DAB, what happens if you use it in an electrically quieter location? Try plugging it in where you currently have the non-humming bigger stereo. In fact, try the all-in-one at that location too, just to be sure.


Standard Member
good thinking.

i did triy the little all in one in the same socket as the bigger stereo. it still made the same amount/type of noise :(

i haven't tried the DAB in that room yet. will do this eve.


Distinguished Member
I think we can safely conclude that the all-in-one is indeed faulty.

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