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Discussion Starter #1
When I connect my receiver (rca output) to my subwoofer amp (xlr input) with an RCA -> XLR cable the speakers produce static and a tone, however there is no static or hum on the subwoofer. The tone is not exactly a hum so I don't think it's ground loop noise, but I am inexperienced and don't really know. The static/tone occurs even with the subwoofer unplugged and the amp is powered off - as long as it is connected to an outlet. The volume of the static does not seem to be effected by the volume on the receiver. I've tried connecting the receiver and amp to the same outlet, different outlets, and both the battery backup and surge protector sides of my UPS. I've moved cables around with no change, so I don't believe it's a noise from induction either. I'd be willing to purchase something like a Furman M-8X AR if I knew it would resolve the noise problem, but since the battery backup didn't change anything I'm hesitant to throw money at a line conditioner. It's probably also worth noting that the Marantz receiver power cable doesn't have a ground.I'll be borrowing a receiver this weekend to rule out my receiver being at fault, but we'll see.
 

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50/60 Hz hum is a common form of ground loop noise but not the only one.

Is this noise loud enough that you can hear it from the seated position while music is playing?
 

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Using a cable box input for your tv?
Yup, that was my next question as well. Cable boxes have a new ground potential: the outer sheild of the incoming RF signal. Sever that, as a test, and I bet your noise will go away, OP.

A ground breaker for that lead is a potential solution.
 
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There's no cable or TV connected. Only my computer plugged into a battery backup, which is connected to the receiver via hdmi. The noise persists even when the hdmi is disconnected leaving the woofer rca connection as the only potential source of the noise.
 

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When I connect my receiver (rca output) to my subwoofer amp (xlr input) with an RCA -> XLR cable the speakers produce static and a tone, however there is no static or hum on the subwoofer.
Am i correct that you are saying the noise is from your main speakers, not the sub itself, and it only occurs when the sub is connected but disappears when the audio connection to the sub is severed, yes?

Must you use this RCA to XLR adaptor or does the sub also have an RCA in? What brand and model is the sub and receiver?
 

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Where did you buy the rca to XLR adaptor and does it have the ability to "lift the ground"?
 

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Discussion Starter #9
Am i correct that you are saying the noise is from your main speakers, not the sub itself, and it only occurs when the sub is connected but disappears when the audio connection to the sub is severed, yes?

Must you use this RCA to XLR adaptor or does the sub also have an RCA in? What brand and model is the sub and receiver?
You are correct. The noise emanates from the speakers, not the sub. The noise only occurs when the amp is connected to the receiver. Marantz SR7011 and a Behringer iNuke NU3000DSP

An adapter is my only option, but it could be an RCA -> TR/TRS cable rather than XLR. I got the cable from monoprice.
 

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Ok I have a plan. The least expensive thing that might work [no guarantee] is some version of this ground lifter (with the right in/out/gender) to match your existing cables :
https://www.amazon.com/Hosa-GLT-255-Female-Ground-Stopper/dp/B00FC4YPL4

A more bulletproof approach is to convert the transmission of sound to the sub amp via optical or RF transmission, but such devices are pricier, say $50 to $100ish. Don't know much about this one but here is an example:
https://www.amazon.com/OSD-Audio-WSK-100-Transmitter-34-Channel/dp/B01C4IOLDM/ref=sr_1_5?s=electronics&ie=UTF8&qid=1535074736&sr=1-5&keywords=wireless+sub+transmitter&dpID=31YQ72QNr5L&preST=_SX300_QL70_&dpSrc=srch
 

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Discussion Starter #12
The iNuke definitely has a noisy fan. Thank you for help and suggestions. I'm happy the report that the noise seems to be gone. But, I'm unhappy to say that have no idea why. If it returns I'll definitely consider that ground lifter. The amp is on the other side of the wall so a wireless rf solution won't work. Case closed for now I guess.
 

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I'm happy the report that the noise seems to be gone. But, I'm unhappy to say that have no idea why. If it returns I'll definitely consider that ground lifter. The amp is on the other side of the wall so a wireless rf solution won't work. Case closed for now I guess.
If the "problem" mysteriously is gone, then IMHO, you've moved/adjusted/played with a marginal cable or connection. A ground lifter won't resolve an intermittent noise issue.
Wireless can work through walls.;)
 

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I was confusing IR with RF lol. Well the noise came back today while I was playing a game. It doesn't make any sense unless the power is dirty and something else in the house is causing it. IDK what it would be though. I thought maybe it was the furnace, but there was no change with that on or off.
 

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I was confusing IR with RF lol. Well the noise came back today while I was playing a game. It doesn't make any sense unless the power is dirty and something else in the house is causing it. IDK what it would be though. I thought maybe it was the furnace, but there was no change with that on or off.
Have you tried moving or wiggling the RCA or XLR connections themselves?

I had been using Monopirce RCA and XLR cables and would have issues similar to what you are describing and it was the connectors not making a good connection. So give that a try if you haven't.
 

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It's an outside chance but I'd try an RCA to TRS instead of the XLR with a different cable
 

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It doesn't make any sense unless the power is dirty and something else in the house is causing it.
Ground loop noise is sometimes intermittent.

Much like lightning the "potential" (electrical voltage) always seeks the easiest path it can find in the area but when that fluctuates or is not dead obvious it may jump around between different paths.

Just because your friend standing next to you is 7 feet tall and you are 6 feet tall doesn't mean you are safe from being hit by lightning because he is the more likely of the two of you to be hit.:)
 

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Getting hit by lightning is more likely than troubleshooting and pinpointing a static/noise/hum/ground loop issue from the internet. :p
 
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OP, does the noise go away when you disconnect all connections to the video monitor ?
 

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OP, does the noise go away when you disconnect all connections to the video monitor ?



There's no cable or TV connected. Only my computer plugged into a battery backup, which is connected to the receiver via hdmi. The noise persists even when the hdmi is disconnected leaving the woofer rca connection as the only potential source of the noise.
:)
 
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