Hum on LP12

I recently has a complete re-vamp of my Naim/LP12 system with 11 Fraims. On setting it all up by my ever helpful dealer we discovered a hum on LP12 when the Panasonic TV was switched on. The TV sound is fed into my 552. Swith off TV and all is well. Its about four years old.
Now before the rebuild I am not sure if the problem was there as I had never tested for it. Who would play a record and watch a silent screen? Not that much if ever.
The joint feeling is there is an earth loop problem. The LP12 even went back to the dealer as a check and all OK.
I am content to live with this as there is an obvious solution. Its just why should it be there?

TV screens usually float at about half mains potential. You’ll also find other things connected to the TV (cable connections etc…) looking for paths to earth. Unfortunately, when you connect them to something like a Naim system, which has a proper earth, the screen will use the interconnect signal earth. This why it’s usually best to use an optically connected DAC between a TV and the Naim system to ensure there’s no route to earth for the TV.


Hi Richard. Many thanks for your input. I will investigate further via my dealer.

Decided to live with the LP12 on and TV off at the same time. Save some money and don’t need both at once.

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