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Having recently installed a new Onkyo 989 receiver and connected my Sunfire True Subwoofer via the Onkyo's sub pre-amp out, I am now getting a constant hum out of the subwoofer.

I have tried the following:

*Turn the volume down on the sub and the hum goes down with it.

*I have disconnected every audio source coming into the onkyo, and it still hums.

*I usually use a Transparent Audio cable to the sub, but I tried several different cables, all same result.

*Lifted the shield on the audio cable, no difference.

*Tried a few different power outlets, no difference.

*Kicked the subwoofer - no difference :)


HELP PLEASE!!!


ps...I am in Australia, so there is a power transformer inline with the sub to convert to 240v. This is supplied by Sunfore when we buy it, and was never a problem with my previous amp. This was at a different house though.
 

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Have you tried:

* Removing the interconnect between the two components to see if the hum persists?

* A different interconnect between the two?

* Using a "cheater plug" on the Sunfire and switching the cheater's orientation within the outlet to see if that gets rid of the hum?

* An in-circuit hum suppressor you can get from Radio Shack (or the equivalent in Aus.)?

* Connecting a different sub to the Onkyo to see if the problem follows the receiver or the sub?
 

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Quote:
Originally posted by dakyman
Having recently installed a new Onkyo 989 receiver and connected my Sunfire True Subwoofer via the Onkyo's sub pre-amp out, I am now getting a constant hum out of the subwoofer.

I have tried the following:

*Turn the volume down on the sub and the hum goes down with it.

*I have disconnected every audio source coming into the onkyo, and it still hums.

*I usually use a Transparent Audio cable to the sub, but I tried several different cables, all same result.

*Lifted the shield on the audio cable, no difference.

*Tried a few different power outlets, no difference.

*Kicked the subwoofer - no difference :)


HELP PLEASE!!!


ps...I am in Australia, so there is a power transformer inline with the sub to convert to 240v. This is supplied by Sunfore when we buy it, and was never a problem with my previous amp. This was at a different house though.
Sounds like a ground loop problem. If you can, plug the sub and the Onkyo into the same outlet. See if the problem goes away. If it does, the outlets that you are using are probably connected to different grounds.


Hope this helps.
 

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Did you disconnect every video source from the receiver? Lots of people find that hum comes from a cable feed.
 

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I had the same problem and it came from my cable TV.


I spent hours upon hours trouble shooting, upgrading interconnects, buying power filters, and re-wiring my HT


Bought a $20 filter from my local dealer that goes in-line with the incoming co-ax cable, problem gone. What should have taken me a trip to the store cost me several Saturday and Sunday afternoons.
 
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