I have the Onkyo TX SR606 set up with the Kef 2005.3 speaker system which includes the new kube 2 subwoofer. When switched on and the subwoofer's led is on red, no hum is heard. When any film starts and the kube 2 turns on with the led green, this is when the annoying hum starts. We contacted Kef and they sent out another kube 2, and to my surprise this does the same. What i did find out is, that when i pull the Qed subwoofer cable out half way from the receiver the hum goes away and the green led light is on, but then i dont get any of the low frequency sounds which the subwoofer is ment to give you.
Please help.
The Kube Sub-woofer is earthed via its 3 pin plug. The Onkyo and other components I have in my system are not (they are double insulated). During normal operation, a difference in electrical potential can exist between these components in the system. I found that this potential was finding a path to earth via the audio cable and on through the subwoofer's earth. The path was via the earth portion of the audio cable and so gave the hum irrespective of volume levels set either on the Onkyo or the sub.
The fix is to ground the Onkyo to the sub. I used a length of electrical cable between a panel mounting screw on the back of the sub and a screw on the casing at the rear of the Onkyo. Try it out with a piece of cable manually touching screws with the bare ends of the cable until you find ones that give continuity( the hum will go immediately). I then crimped a small fork end electrical fitting onto each end of the cable which can be slid under the slighly loosened screw head and resecured. All I hear now is the fan on the Blu-Ray player!
Thankyou, Thankyou, Thankyou. I did as you suggested and it was like magic it worked straight away. I've been messing around trying to sort this out for ages. Much appreciated.
Yes, thanks - fixed the problem for me, though why it started after I've had he Amp and SW together for at least 4 years is a bit of a mystery (I tried different SW cables)
Thank you for this I was ready to throw my sub out of the window. As my sub is some distance from my amp, I grounded it through one of the speaker terminals which creates the ground as you suggest. Although the humming started after I bought a new TV and hadn't been there before, unplugging everything did not work, but with your method the humming stopped immediately, what a relief :)
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Found that the source of the hum on our system was the Sky+ HD box.
This was solved by connecting an insulated wire from a screw on the back plate of the Sky box to a screw on the back plate of the Kube.
Upgrading to a SkyQ box shortly and expecting to be able to do away with the wire.
You have a ground loop. That is, the grounds of your reciever amp and subwoofer amp are meeting up at more than one point. They should only be joined by the cable betwwen receiver and sub. Here are some things you can try...
- Be sure all of your accesories (including any connected video) are plugged into the same outlet. Of course you will need to use an outlet strip (preferably a surge protector) to do this. This will join all your electrical grounds at one point.
- Use a "cheater" plug. These are the ones that convert a three-wire outlet to a two-wire by removing the ground. Use it on the power plug going to the Kube. This will break any ground loop between those components.
- Temporarily disconnect your TV cable or sat dish. Sometimes the ground there causes strange things to happen. If that cures it, you will need a cable transformer.
Good luck !
Marco
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Hi, I have exactly the same problem. Brand new Kef Kube 2 makes an annoying hum when it goes as soon as it's operational. i.e. red LED turns to green.
Totally unacceptable, even for a cheap system, let alone this expensive one.
Be glad to hear of any solutions, before I send this system back which is a shame as I like the satelites!
I have the same equipment set up Onkyo SR606 and Kef 2005.3 speakers. The annoying hum pervades the room and once heard is difficult to ignore. I have tried re-arranging all my cables to separate power from audio etc to no avail. All my system (including hi-fi) is through a 10 way surge protected pillar. I have tried separating the systems into 2 supplies but this has had little effect. I started to notice the hum after I had installed a new TV but disconnecting the TV totally does not make any difference so I suspect the noise was there before.
Same, ish...Onkyo 606, Super Cube 3 Sub - loud hum. With all leads disconnected from the sub and the AVR off - hum? Could this still be a ground problem if the sub is the only thing powered on? I took it back today and got a new one, it hums....
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