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I suspect I have a ground loop problem in my AV setup. It varies depending on the volume of the receiver. The TV and receiver are both plugged into the same outlet. I have also tried moving the PC that its plugged into across the room and plugging that into the same outlet as well which didn't seem to help at all.

It is defiantly worse when the source is my PC (but no change depending on whether or not its plugged into the same outlet).
When I chose any other source on the receiver it gets better (but is still there) even if that source has nothing hooked up to it. However, when I chose Bluetooth as the source and use my phone via Bluetooth there is 0 hmm at all.

This problem has been consistent through adding a center speaker and sub, as well as moving the whole setup around the room a few times. I have tried rearranging the cables as well. All of the speakers and receiver have good reviews as well. Also using these sample clips How to find and fix hum in 3 easy steps – PS Audio it appears to be a 60hz hum.

Any help would really be appreciated, it's pretty loud and drives me nuts!

Setup
  • 2x Pioneer SP-FS52 Home Audio Andrew Jones Designed Floor Standing Loudspeaker
  • 1x Pioneer Sp-c22 Andrew Jones Designed Center Channel Speaker
  • 1x Klipsch - R-80SWi Wireless Pre-paired Subwoofer
  • Onkyo - TX 5.2-Ch. with Dolby Atmos 4K Ultra HD HDR (Model:TX-SR393)
 

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What about when the PC is completely disconnected from the Onkyo?

Assuming it is the PC, don’t use the RCA audio outputs from the PC. Instead, use optical outputs from PC and connect to the optical input on your Onkyo (which is assignable, so you can assign it to ‘PC’). If your PC sound card doesn’t have optical outputs, it is pretty cheap to buy a new sound card with optical output.

good luck
 

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Cables are always the number 1 culprit. I have ONE very, good, and pricey cable that has to be periodically pushed in a fraction of an inch to get a good ground that always stops the hum until the next time I have to push that 1 cable back into the socket snugly. Don't assume EVERY hum is a ground loop. Sometimes it's just a cable that's not fully seated, even if it LOOKS fully seated. Also, you can narrow-down which cable is causing the problem by disconnecting the cables 1 at a time. Unplug BOTH ENDS of 1 cable at a time. When you find that a single cable is responsible for the hum, try a different cable from another channel that you KNOW is working properly and see if there is any noise with the OTHER cable connected. And "cables" includes power cords. Some detachable power cords have a very tentative grasp on the ground pin in the IEC socket. Trying a different cable that has the ground-pin contacts closer to the hole in the socket might reveal the hum was a marginal or no ground connection for the ground pin on the power cord.
 

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Try unplugging every device (TV, PC, LAN, etc.) from the receiver, so it's just the receiver and the speakers hooked up. Unplug and turn off the subs. Does the hum go away?

If it does not go away, it's a problem inside the receiver and probably means repair or replacement.

If no hum yet...

Turn on the subs. Does the hum come back? You can focus your energy there to resolve the issue.

Still no hum? Then plug in just one source device at a time and check for hum each time. Does the hum come back? Then that device is the culprit. Fixing it here could be resolving a ground loop, but it could be the device itself.
 
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