Sub mains hum

[RobinKidderminster]

Only just noticed a mains hum on my MS sub. Set to 65% and hum is only noticeable in quiet pieces. Silenced at around 40-50% - mains & signal cables neatened by joining with cable ties. No hum through mains. Any comment to suggest this is normal or not? Cheers.

 

[Sliced Bread]

it's sometimes worth systematically unplugging things in the home (especially if they are closer to the sub).

i found the dock for my chord less phone which was plugged into another socket about 2 foot away was causing mains hum in my sub. I moved it to the other side of the room and now all is good.

Ive heard of fridges having a similar impact even if they're in the next room.

its also possible that the transformer in the sub has a natural hum too. The monitor audio rx12 does.

 

[macdiddy]

Hi there.

Can I ask if the hum was noticeable before you joined your signal and mains cables together.

I'm sure someone will disagree but I've read in most magazines including What Hifi that signal and mains cables should be kept apart

If you joined them together before the hum appeared then please ignore this advice.

To answer you last comment, I don't think its normal to hear a hum from your sub, my MA BXW10 is silent even when on standby, so you may have a problem with the amp inside the sub.

*dance4*

 

[RobinKidderminster]

Cheers both - will try your suggestions.

 

[Glacialpath]

My sub used to hum ans was between my AV rack and the right front speaker. When I finally got to move it to the corner of the room away from them both, the hum went.

Where is your sub positioned?

 

[RobinKidderminster]

That sounds like cable proximity - one possible cause in my setup. My sub is.to one side of fronts.and amp.but as I said - cable ties maybe the cause.

I may have had the hum since day 1 and not noticed which is why I look for confirmation that a sub set to 60-70% volume should be silent.

I will try removing the signal lead, separate the leads & check.other appliances. I guess unplugging all the sound kit and signal lead - then turn sub on in different socket - see what happens.