Originally Posted by _Avarice_
So after 4+ years of flawless service, my 663 seems to have developed an issue out of the blue...
Whenever the input or audio signal changes (from 5.1 to stereo, for instance, when watcing television) there is an audible single "pop" through the subwoofers. This also occurs any time the "mute" button is pressed.
Now, I know for a fact that this was not occurring yesterday; and the only thing that has changed since yesterday is a visit from the DirecTV technician. I called them to come out and correctly ground my satellite dish (was left ungrounded when originally installed). I didn't realize this until I moved some of my equipment to a new 20a circuit and was getting a nasty 60hz hum through the subs. Traced it to the satellite by systematically unplugging each input.
So....he grounded the the dish and the hum is gone. However, at some point this afternoon the system began making this noise when switching inputs or signals, or when mute is pressed. It is quite annoying, especially since many relays are triggered, say, when watching a blu-ray, as it switches between differently encoded audio tracks on previews, menus, and features.
Has anybody experienced this phenomenon with their 663? Is it a grounding issue, do you think, or some coincidental electrical issue from a surge, etc.?
Odds are 50/50 that this "pop" is being generated in a sub. It's usually caused by a ground "potential" that is discharged in the sub amp and propagates to the other sub(s) on the same line-level loop. I've experienced the same sort of thing here, and the pop was propagated to 2 other subs from the offending one. (all 3 were on a single line-level daisy chain). What causes the discharge is any interruption in the signal, like stopping, pausing, changing inputs, chapter skips, etc.
If you have multiple subs, you can easily troubleshoot which one is the culprit by disconnecting one at a time. Another test for each sub is to connect a CD player's line level out to the sub and try to reproduce the pop. Be sure to lower the level on the sub prior to doing that.
Odds are also good that the same sub was the real cause of your 60Hz hum, with a ground loop through the DTV box. You can try the usual steps for eliminating grounding issues, which may or may not resolve this, but it could be that the sub needs service.