Onkyo 605 Subwoofer problem

[bostock]

I'm experiencing a constant hum from my subwoofer whenever it is connected to my Onkyo 605. It doesn't matter if the receiver is on standby or it is fully on, the noise is constant. I have changed out the sub and the cable, so I'm sure the problem is the receiver.

Any ideas what the problem might be?

 

[Davemcc]

I you have a cable TV receiver anywhere in the system, you may have a ground loop. To test this, disconnent the screw on cable feed from the back of your cable box. If the hum stops, you can fix this with an inexpensive ground loop isolator.

 

[bostock]

Unfortunately when i swapped out the cables and sub to test the receiver I disconnected everything else to avoid any interference from anything else, so the issue can't be related to any of the components it is hooked up too.

Thanks

James

 

[Adam]

Welcome to the forum, James.

Dave was mentioning a common source of a ground loop. There are others. I'd suggest checking out two articles on ground loops on the Audioholics main site at the links here and here.

We'll be happy to try to help you get rid of the hum, but I'd suggest reading those articles first to get a primer on what might be causing this.

 

[TLS Guy]

Unfortunately when i swapped out the cables and sub to test the receiver I disconnected everything else to avoid any interference from anything else, so the issue can't be related to any of the components it is hooked up too.

Thanks

James

Are you telling us that the sub hums even if there are no connection made to it? In other words, does it hum when the only connection is to the mains, no other cables going to the sub? If it hms under these conditions, then the sibs power supply has failed.

If it is silent just plugged into the mains, but only hums as soon as you connect it to the receiver, it is a ground loop. You can go to the bank with that.

 

[bostock]

Thanks everyone. Ground loop it is. I changed the outlets recently and that appears to be causing the problem since it no longer hums when i use the outlets in another room.

Thanks again

 

[Adam]

Thanks for the update!

 

[bostock]

I turns out I didn't fully turn the subwoofer on when I tried in the other room (the light was on to show power, but the sub wasn't actually on). When I turned it on I got the same hum as usual.

This room I didn't change the outlets in, so I'm not sure if it is still a ground loop problem. One thing to note is that when the receiver is in standby the hum from the sub is louder than when then receiver is actually turned on.

 

[Adam]

James,

Is this a new set up for you that has had the hum since you first hooked it up, or is this something that just started happening?

 

[bostock]

It just started happening, ever since I changed the outlets. Is is possible to have blown a fuse? I don't get any sound from the sub other than constant hum.

 

[Adam]

This is not meant to sound insulting, but it happens sometimes, so I'm going to ask. When you were rearranging things, are you sure that you rehooked the subwoofer cable to the subwoofer output jack on the Onkyo and not to the subwoofer input for the multi-channel analog inputs?

 

[lsiberian]

This is not meant to sound insulting, but it happens sometimes, so I'm going to ask. When you were rearranging things, are you sure that you rehooked the subwoofer cable to the subwoofer output jack on the Onkyo and not to the subwoofer input for the multi-channel analog inputs?

Hey no one would ever do that.

Actually it didn't hum when I did that to mine. So I doubt it's that. Though I hope it is. That's an easy fix.Make sure you isolate the sub form the receiver plug. If it hums by itself with no other devices hooked to it. Congrats your Subwoofer has just become an intelligent life form. It will likely need repair. If you know what you are doing you might be able to do it yourself. It is quite possible the plug is messed up some how. Subs can be very sensitive to stuff. I suggest a thorough check of your wiring. If there is a problem that's never good.

 

[bostock]

I just double checked that, and unfortunately it is hooked up correctly. I also went into the receiver menu and did the white noise output, and the hum remained the same even when i switched it to subwoofer.

 

[bostock]

I'd say it isn't the sub as I still get the hum when I used a different one.