[leo79]

I know this has been covered a million and one times, so apologies for bringing it up again.

I've always had a hum on my Monitor Audio RSW-12 and today I've tried to sort it.

I've disconnected the RCA lead from Sub and I'm still getting hum. I then tried it in a different socket still humming, I then made up a temp cable with earth disconnected at both ends (I'm a sparky so I know this is wrong but I'm only trying to work out whats causing it) and it's still humming.

Would this suggest that it's to do with the transformer in the sub?

Thanks

Leo

[Moonfly]

Lave the sub plugged in an turn off all other electrical devices on the same ring. If it stops then you know its being caused by another device in the loop. Fridges etc are favourites. If it still hums, then its the subs amp itself.

[leo79]

Thanks moonfly.
I've got all av equipment on it's own radial circuit so i knocked off all other breakers and just left sub plugged in, still humming

I've had the back off the sub to check there are no loose connections or screws and everything seems ok. Would fitting a new transformer be possible?

thanks

leo

[Moonfly]

Well I guess in theory its possible, but I wouldnt be able to advise on that. Can you hear the transformer humming, and is it audible through the cone?

Perhaps giving MA a call is the way forward, it could be a faulty transformer?

[noiseboy72]

Sounds like a dried out or dry jointed capacitor on the power supply. I assume as a sparky you have a soldering iron, so open it up and have a good look around the power supply. If it hums with nothing else connected and the hum is constant, it sounds like an electronic fault. As suggested a poorly wound transformer can cause hum, but this is unusual and would have been picked up in QA.