Just connected up my Behringer nx3000d hum problem

AVDavid

Active Member
Connected my Denon x4700 av receiver to my Behringer nx3000d using an RCA to XLR adapter and I get a hum / buzz from my main and surround speakers. I suspect it is caused by the adapter unbalanced to balanced signal, has anyone else had this issue?
I am thinking of getting a RCA phono to 1/4 inch TRS jack adapter which the Behringer also accepts so it now unbalanced to unbalanced.
Previously my subwoofer had a bk electronics MOSFET 200watt module inside the cabinet with no issues, I changed to the Behringer because 200w is not that much to power 2x audio drive ad300's
 

AVDavid

Active Member
Did some further research and the hum occurs when I turn on my transmitter for my Epson 9300W projector which is plugged into the same double wall socket, the hum is reduced when I got my extension lead and plugged the transmitter into a socket in another room. Does anyone know if I can buy something to remedy this?
 

noiseboy72

Distinguished Member
A line isolator for the audio into the Behringer is probably the most straightforward approach.

 

AVDavid

Active Member
Thanks for the reply, the Behringer gives you the option of having an unbalanced connection via a 1/4" TS adapter which I have ordered so I will see if this fixes it as before I got the Behringer I had 2 amps feeding my subs RCA to RCA connected with no problems
 

noiseboy72

Distinguished Member
I doubt it will make any difference. Running unbalanced into a balanced connection is the same as running fully unbalanced and it's the amplifier earthing that's causing the issue.

Breaking that earth loop with a transformer and ground lift is likely to be the cure, but perversely it can sometimes make things worse!

The actual issue is that somewhere in the video side there's a link between the mains earth and audio ground and the Behringer amplifier is then providing an alternative earthing path and a buzz is the result.
 

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