Moosergooser wrote:

Have a Harmon kardon avr 225 with infinity speakers. Recently, I noticed a buzzing out of my front right speaker at very low volumes. The Buzzing is virtually gone at normal volumes and above. I switched the front speakers and the buzzing stayed in the same location, so I believe it is a problem with the receiver. The buzzing is loudest at the lowest volume and gradually get softer as I increase the volume. Totally gone if I mute or unplug the input. Input is a optical cable. 

Impossible to diagnose at a distamce, I am afraid, but it does sound as if something in the D/A section of your receiver has failed. Have you added any other sources? Do you get the buzzing if you switch to other inputs?

John Atkinson

Editor, Stereophile

Hi Moosergooser

What you described sounds very similar to what I did months ago. 

I first swopped the speakers around to determine if I might have unknowingly damaged them. Thereafter I swopped the speaker cables althought after speaking to the local dealer realised was unnecessary, that's a component which doesn't trip often esp with banana plugs. 

When it doubt I think an additional source always helps with troubleshooting as John mentioned. I finally used a standard audio cable to hook up my iPod realised it was the amplifier. 

Hope this helps and good luck.