Another issue with dimmers that I have experienced specifically with LEDs is mechanical noise.
I have recently installed three dimmers, two for use with LED pot lights and one for ceiling lamp that uses standard style bulbs, but still LED.
I installed the ceiling lamp dimmer first, using a Levitron brand dimmer and Sylvania brand bulbs. These bulbs buzzed, despite being labelled dimmable. The buzz was very audible and coming from bulb as well as the dimmer.
In the dimmer's literature it stated that it only worked for specific models of bulbs. I had on hand a Phillips bulb that was listed for use with dimmer. I swapped bulbs and voila no buzz from either the bulb or dimmer.
I was lucky with the pot lights, these weren't listed but only cause a buzz on occasion and hardly noticeably. I don't know the brand but are likely Chinese.
All this to say that dimmer noise is dependent at least in part to the type, model and brand of bulb used.
Also I have not heard any dimmer induced noise in my system since installing the dimmers.
Finally, to answer the OP, when switched off all noise stopped.
I have recently installed three dimmers, two for use with LED pot lights and one for ceiling lamp that uses standard style bulbs, but still LED.
I installed the ceiling lamp dimmer first, using a Levitron brand dimmer and Sylvania brand bulbs. These bulbs buzzed, despite being labelled dimmable. The buzz was very audible and coming from bulb as well as the dimmer.
In the dimmer's literature it stated that it only worked for specific models of bulbs. I had on hand a Phillips bulb that was listed for use with dimmer. I swapped bulbs and voila no buzz from either the bulb or dimmer.
I was lucky with the pot lights, these weren't listed but only cause a buzz on occasion and hardly noticeably. I don't know the brand but are likely Chinese.
All this to say that dimmer noise is dependent at least in part to the type, model and brand of bulb used.
Also I have not heard any dimmer induced noise in my system since installing the dimmers.
Finally, to answer the OP, when switched off all noise stopped.