Moving my surround sound system


Standard Member
:lease: Hi,

I wonder if any one could point me in the right direction please?

I have just moved my Sony Home Theatre system from one room to another and i have a problem with my Subwoofer.

The old Amp to Sub lead was too short so i bought a 3m Phono to Phono Lead, which on the packet it says 'carries video picture from DVD to TV,' to replace the other cable.

The problem I have now is that when i turn the Amp off and leave the Subwoofer on it hums, and the volume of the hum goes up and down. When i unplug the new phono to phono lead it stops. When the amp is running i have no problem with the sound.

I have tried a temporary replacement with an old 1m phono to phono lead with yellow boots on, which i assume is for a video signal? Again when i turn the Amp off the noise starts. When i unplug the lead it stops. It is still like this if i only plug the end into the Subwoofer only and not into the Amp - it still hums.

My questions is am i using the correct lead, as in my Sony Operating Instruction booklet says the lead between the Amp and Sub is a Monaural audio cord, which searching on google does not tell me much!

Any advice would be gratefully received.



Established Member
Monaural audio just means a single channel, as in 'Mono'.
Is the cable a proper coax cable or just thin black wire with yellow phono plugs?
If it's a thin black cable, it wont be up to the job.
It sounds like the cables shielding might not be good enough so the cable is just picking up mains 50hz signal from near by mains cables and equipment. Also, the cable might be earthed only on one side. Swap the cable around so that what was plugged in the amp is plugged in the sub and visa versa. You can also just unplug the cable from the sub end. If the hum goes away then the cable isn't up to the job. Invest in a proper coax sub/video cable.


Standard Member

Thanks for the advice, it is a very cheap cable from B&Q, so wont be upto the job.

I have ordered a specific Subwoofer cable now.

Thanks again


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