Hum coming from speakers even when volume off...

[tbessie]

I'm still having some worries about this Onkyo Integra DSR-7.3 all-in-one I bought. The speakers are constantly emenating a low-volume hum, even when the unit is muted and the volumn turned all the way town and no active signal source is present.

I can't decide if this is my speakers (very nice B&W speakers, but that had been sitting in the garage for 2 years), or the unit having very bad circuitry to keep transient voltage from getting to the speakers. I already am a little perturbed that when you switch signal sources (for example, by putting a DVD into the unit), the speakers emit a light "pop".

Would any of you call this unacceptable in a $600 unit?

- Tim

[tbessie]

Well, I tracked it down.

I have the all-in-one's Component Video Out going to a flat panel TV, and also the unit's CD-audio-out going to the audio input for that same TV. When I unplug all of the Component Video plugs, or all of the audio plugs, the hum in the speakers goes away.

So it's like some kind of loop is occurring, perhaps current circulating through the video and audio circuitry. I wonder if this speaks to bad isolation of circuits in either the TV or the AV receiver or both. Weird.

Anyone know what to do in a situation like this? This happens even if the TV isn't plugged in to power, so it's some sort of crossover happening in the circuitry itself, it looks like.

- Tim