Dedicated line (almost)

Modern dimmers and LED replacement bulbs are much quieter (both electrically and mechanically) than old one’s, especially compared to LED lighting with plug in power adapters.

If you have new LED bulbs with old school, turn to dim controls you probably want to upgrade those dimmers, and I even recommend skipping new LED aware dimmers and going straight to smart switches.

I’ve found that the modern, but dumb dimmers are not only hard to calibrate, but tend to be far too voltage sensitive. After swapping out dimmers in my house a little voltage change from the AC or other appliance would cause the lights to dim or brighten noticeably. Replaced them with smart switches and those problems all went away.

https://amzn.to/44AB1HJ

Interesting!! I was not aware that modern / smart switches are quieter.

When I say I have 3 dimmers on the line, I would have say 3 smart dimmers / switches (enbrighten / Hilo one's). If these are really much quieter, I won't bother. I will try to find a way to measure this (anybody : If you know an easy way to check this?).

Thanks...

How long is the circuit and what gauge wire is it?  How many junctions in the wire and how well are they made up?  

I do not believe  you cannot cheat and get the majority of benefits. A direct line, takes the shortest distance between a breaker box and the outlet, it does not go wandering off and connect additional outlets (even if unused… these are sources of resistance), and is normally 10 gauge wire. The longer the run, the more likely it picks up noise.

So, a direct line is dedicated and direct, with thick gauge wire.

Do not know exactly the length of the circuit and the gauge. The breaker is 15 amps and the house is 10 years old so it is to new standards. Think I will buy a probe to try to follow the line and know better it's length and so on