Subwoofer Buzz with Amp

  • 1 March 2021
  • 3 replies

I am getting a significant amount of buzz with the subwoofer. Very loud. It is noticeable when hooked up to the Sonos Amp. If I disconnect the RCA wire, it stops. I tried to change outlets but it did not help. I changed RCA cables also with no improvement. Again, it is only when the RCA cable is connected to the Amp, it does not occur if the sub is powered on but not connected.

Is there something wrong with the Amp? I cannot use the sub like this; it is intolerably loud.

3 replies

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Hi @cmb13

I presume you are referring to a third-party subwoofer connecting to the RCA port on the Amp?

If so, you may need a ground-loop isolator to get rid of the noise. These are inexpensive and available at Amazon. Note that they come as stereo, but you will only need to use one channel for your subwoofer.

Essentially, the subwoofer and Amp are disagreeing about what level “ground" is at, and this difference creates a background noise usually experienced as a buzz or hum. This is quite common with audio equipment that is electrically connected but draw power separately using different transformers.

If you have a Sonos Sub, that’s different, and shouldn’t happen at all (no wire connecting the two) unless the noise is coming from whatever is connected to Line In (in this situation I would expect buzzing from the left and right channels too). The solution would be the same.

I hope this helps.

Hi all….I just upgraded from an old Sonos Connect Amp to the new black Sonos Amp.  Luv the improvement in sound and bass (from 55w/channel to 125w/channel).  However, I’m experiencing the same buzz when my sub is ON but there isn’t any music being played that cmb13 posted above.  This was never the case with the old Sonos Connect Amp though (even if it was there, it wasn’t no where as “loud” as the new Sonos Amp is).  I’m using a 12” Klipsch R-12SW sub with a fairly new RCA subwoofer cable connected to the new Amp along with (2) Klipsch floor standing R-26F speakers and with (2) BIC America in-ceiling speakers (parallel wired).  I normally turn my sub off manually when there isn’t any music being played.  Quite frankly though, the buzz isn’t that loud but it’s bothering the crap outta me whenever I go into that room and am sitting down to do something (like whenever I forget to turn the sub manually off OR whenever I’m just done playing music).  Corry P, which ground-loop isolator (amazon link?) do you suggest/recommend that I pickup to try to eliminate the buzz/hum?  Any advice would be greatly appreciated.  Thanks!

If it helps anyone, I ended up fixing my humming issue by replacing the sub cable with a Dual Shielded one purchased from Amazon.