Horrid buzz on av pass through

Posted by: John Hoptroff on 23 October 2017

I recently bought a 272 and I love it for music. However when I use it for the front speakers of my AV system it makes a (probably) 50hz buzz. I’m thinking that my AV amp is somehow on a different earth to my 272 and causing some feedback. Any suggestions?

Posted on: 23 October 2017 by Richard Dane

John, there's plenty of info on this on the forum if you do a search.

Your AV amp probably floats its earth, which, combined with any connected Av devices (which probably also float at half mains potential) and any cable system, looks at the audio connection to earthed Naim kit (which is always properly earthed) as a nice route to earth.

You could try running lifting the signal earth on the NAC-N272 (via the switch on the back - follow instructions in the manual), or run a separate earth from the case work of the AV amp, or else use an isolator between the i/c running between AV amp and NAC-N272.

Posted on: 23 October 2017 by Adam Zielinski

Sounds like a ground loop problem.

What Richard is reffering to in his last sentence to is a stereo 'isolating transformer' with two inputs (RCA sockets and two RCA plugs on the other side). It is quite effective at eradicating ground loops. Approximate price - EUR 10-15.