Woken up in middle of night by sub loud humming

Trum

Standard Member
Good morning all

I recently set up a Denon 2600 with wharfedale dx-2 5.1.

Sub is connected to amp output 1 to sub lfe by BlueRigger Dual Shielded Subwoofer Audio RCA Cable.

If i touch the cable the sub lets out a horrible loud hum.

Last night i went to bed all fine then at 3am sub went off, super loud humming thud noise. Nothing touching it.

Any ideas?

Thanks.

Tris
 

Ultrasonic

Well-known Member
The 'thud noise' doesn't sound good. Does the sub work now?

I wouldn't leave a sub on overnight personally. It's a waste electricity.
 

Trum

Standard Member
So it happenes no matter where on the cable i touch. I was trying to move some power cords from the back and it went off. If i turn the gain down on the sub it stops.

Ill check to make sure its in the amp fully.

Ive seen this problem on the net before but cant remember the outcome.

The sub still works fine.

Thanks.
 

noiseboy72

Distinguished Member
If the heat sink is getting hot, there is a fault somewhere that needs fixing.

My guess would be that the cable is either faulty or highly microphonic - IE: It's picking up acoustic noise from being touched and is even causing a feedback loop. If you've not already done so, I would replace the cable to start off with. Check also that all the equipment is earthed correctly and that the earth connections have not been removed or isolated in any way.
 

gibbsy

Moderator
If your sub is hot in the middle of the night then turn it off at the mains for safety sake, that's your safety not the subs. Either that or check your smoke detector.:nono:
 

Ultrasonic

Well-known Member
When it went off last night that heat dispenser plate on the back was very hot!
A sub playing a continuous low frequency sound will do this. At mains frequency (50 Hz) I'd expect it to be clearly audible before this would be an issue but if is was lower than this then it could well not be.

As above, definitely don't leave the sub on overnight or when you're out until you've got this sorted for safety reasons. It wastes electricity doing so anyway.

Try a different cable and report back.
 

Trum

Standard Member
Ok guys thanks for the responces.
I just moved a few things around so had the sub off.
Turned back on and fine touched the rca cable sub end ( the cable jacket not the metal end) while plugged in and on and it did it again. VERY LOUD continuious humm until i turned the gain down or the sub off.

Turned back on and its fine.

I have another cable coming next week. Ill try that.

Tris
 

shotokan101

Distinguished Member
If I read your post correctly and it's the outer part of the RCA cable you touched and not the centre connection then it definitely sounds as if your cable is knackered as touching the outer part shouldn't send any signal to the sub's amp circuit - unlike the centre connection..... ?

maybe worth checking that there's no small segments of wire shorting out between the outer and inner connectors inside the plug ?
 

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