Question Speaker Buzz/Hum via S/PDIF Optical


Feb 9, 2018
I have an LG TV with one single S/PDIF optical sound output. It is connected to a Sherwood 5.1 HD Receiver, and over the past while I've noticed a rather audible buzz/hum coming from the speakers when watching TV. I've done some research and tried a few things, but I cannot seem to get rid of the noise.

The noise level goes up and down with the volume control, and it only comes out when there is an active feed but the feed is quiet, like a quiet part of movie, or when Netflix is buffering. Otherwise the TV can be on and nothing can be heard no matter how high the volume goes.

I've tried:
  • Different power bar
  • Everything disconnected except Receiver and TV
  • Everything connected to one single outlet
  • New optical cable
  • Various Inputs to TV
The noise remains audible. I've also tested the composite analog inputs to the receiver, and connecting it to various mobile devices like phones, lappy, etc. Those are noise free. The issue seems to be related to the S/PDIF.

I don't have another audio device with S/PDIF to test the TV's output, and I don't have anything I can move to the receiver to test the S/PDIF input port.

I'm just wondering if there could be something blatently obvious that I'm missing...?

Any help is much appreciated. Thanks!
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