I've got this weird problem. Ever since I unplugged my Denon from my surge protector/power conditioner a few months back, my Denon makes this weird "boing" noise when I power it on.
I didn't turn off the surge protector before I did this, and now I'm regretting to forget this simple little task.
The receiver won't make this noise all the time. Maybe once every 3 or 4 power-ups from stand-by (it's always on stand-by) will it make this noise. Other than that, normal "click" will tell me it's on most of the time.
Is this something I should be worried about? Power output to my speakers seems fine, as does video output.
D Singh: My HK AVR 335 does this ocassionally. This sound,a "boing" is the inrush current to the transformer when AC power is applied.(turned on) This will not harm your speakers since the transformer and rest of the power supply briefly disconnects itself, a matter of a few miliseconds,not noticiable,and the reconnects itself back to the rest of the circuitry of the unit. This is a necessary process that is used by any device that has a transformer in it, this prevents the inrush current from becoming to high which can be harmful for electronics and the AC power feeding them.This boing sound is the magnetic field that develops nearly instantaneously between the primary and the secondary which are magnetically coupled rather than electrically coupled. This magnetic coupling reduces harmful spikes present in the AC input considerably between the primary and the secondary. There is nothing to worry about but I strongly suggest you use your surge protection again if you are not. Although it won't hurt, I also suggest that any component you must unplug make sure that it is completely powered off(no standby).