Alpha:Noise from speaker when bezel lights flash

[DF777]

I only noticed this after a game change.There is a humming kind of noise that only happens
when the bezel lights activate,either from a win or from the test screen.The noise is
perfectly timed with the bezel lights pulsing and is only from the belly speaker.
I have checked the speaker wires all the way back to the backplane and replaced the amp.
Is this anything I should be concerned about as I can live with it if it is not harming anything.
Thanks,

[rickhunter]

It's interference.  All machines I have do it, most of the time I don't hear it because of the gameplay sounds.  About the only way to get rid of it, is to isolate the amp circuit power supply with a noise filter.  It also seems to be more noticeable with certain colors on the bezel.  Like Red does not seem to be "loud" but white tends to get "loud."  If you do a bezel test, you will hear the difference as it tends to cycle through various colors.

[DF777]

Thanks Rick.I did the bezel test and did notice the difference in the noise to color ratio.
My old game had red and the new one is blue so that's why the difference.