Noisy power supply for laptop

[tomp]

If the ground on the outlet connected to the secondary side used to power your equipment is connected to the input ground you are correct about not having any protection from ground noise.

[tomp]

Also remember that since in my case a piece of my equipment, the laptop, was the source of the noise, any other equipment connected to that ground circuit would be in the noise path. In your case if one piece of your equipment was the noise source, any equipment connected to the conditioner would have the problem even if you lift the ground at the conditioner input (not recommended for safety reasons). I had to locate the source of the ground noise and isolate it from the other equipment as far as the ground circuit.