Getting slight feedback/interference from source to integrated amp
Sep 22, 2022 at 10:00 PM Thread Starter Post #1 of 14

thefiend1

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Hello!

Im currently running Windows 11 where my audio files live and I have it hooked up to a Rotel Integrated amplifier via optical cable. For some reason Im picking up some interference that I can hear with and without the source playing. I tried another amp and I also hear it. This doesn't matter if im using headphones or speakers so.

I can even hear a difference in the interference when I use the scroll wheel on my mouse (which is wireless).

Any suggestions on how I can fix this?

Thanks!
 
Sep 23, 2022 at 3:58 AM Post #3 of 14

thefiend1

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This is ground loop. Try to move source and amp to the same or different outlets. What always worked for me is this.

Thanks Andrew, do I plug my amp into that or my computer?

Also I think I may have resolved it - I think it was due to static build up coming from one of the usb inputs. I started unplugging things and it did nothing but then I waited awhile and eventually the static interference went away!
 
Sep 23, 2022 at 2:25 PM Post #4 of 14

thefiend1

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Damn, it came back. @Andrew_WOT They are both in the same power strip but I can try to move it to a different one. For that plug that you recommended - should I plug my amp into that or my computer?
 
Sep 24, 2022 at 3:36 PM Post #6 of 14

tjl5709

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I really question if you have a ground loop between the PC and amp. If you were running the amp via coax or usb, maybe, but optical is not a conductive cable. I see no way to create a conductive loop between the source and the amp if the only connection is optical. Your GL is elsewhere within the PC and any other wired connections (monitor, usb hub, printer.......). Is it a desktop or laptop? Could you have a power supply issue? Something is generating signal noise that is getting processed into the sound stream.
 
Sep 28, 2022 at 6:11 PM Post #7 of 14

thefiend1

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@Andrew_WOT @tjl5709 I tried switching to a couple different outlets and used the Hum-X with the amp and no difference... even tried the pc in the Hum-X with no difference. This is a desktop computer that I built a couple years ago.
 
Sep 28, 2022 at 7:41 PM Post #8 of 14

yage

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Do you have a source of wireless signals (wi-fi, Bluetooth) placed close to your amp? Any light dimmers on the same circuit as the amp?
 
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Sep 29, 2022 at 3:42 PM Post #10 of 14

thefiend1

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Do you have a source of wireless signals (wi-fi, Bluetooth) placed close to your amp? Any light dimmers on the same circuit as the amp?
The PC has bluetooth enabled with a few bluetooth things connected to it. There are light dimmers in the house but its old wiring and im not sure whats hooked up to what. Need to check the circuit breakers to see which outlets are on the same circuit as the dimmers.
If you disconnect amp from PC, does buzzing persist? If yes, it may be something like radio interference.
I unplugged the optical cable from the amp and the buzzing stops - plugged it back in and I can hear it. I tried replacing the optical cable with a new quality cable but it made no difference.
 
Sep 29, 2022 at 3:49 PM Post #11 of 14

Andrew_WOT

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The PC has bluetooth enabled with a few bluetooth things connected to it. There are light dimmers in the house but its old wiring and im not sure whats hooked up to what. Need to check the circuit breakers to see which outlets are on the same circuit as the dimmers.

I unplugged the optical cable from the amp and the buzzing stops - plugged it back in and I can hear it. I tried replacing the optical cable with a new quality cable but it made no difference.
Optical cable is galvanically isolated, are you sure you are using optical and not coaxial.
Unless there is some possibility that your PC audio interface encodes noise into signal it sends over as PCM stream.
 
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Sep 29, 2022 at 4:37 PM Post #13 of 14

yage

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I unplugged the optical cable from the amp and the buzzing stops - plugged it back in and I can hear it. I tried replacing the optical cable with a new quality cable but it made no difference.

Hmm... try disabling your inputs to see if that makes the buzzing go away. I assume you're on Windows - go to Control Panel -> Sound -> Recording tab -> right click on all your inputs and disable them.

https://helpdeskgeek.com/how-to/record-sound-using-line-in-microphone-windows/
 
Sep 30, 2022 at 7:04 AM Post #14 of 14

Roseval

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I can even hear a difference in the interference when I use the scroll wheel on my mouse (which is wireless).
This is a phenomena also reported by users of a USB DAC's.
It might be a CRC error.
This means the data get corrupted e.g. a insufficient shielded cable from mobo to a USB socket in the cabinet.
Do you have discreet sound card?
Unshielded wires connected to a SPDIF header?
Just some guesswork of mine but it might be a pointer in the right direction.
 

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