Power conditioners often, being filters, limit maximum current reducing dynamics. Most of power supplies consisting of transformer, rectifier and capacitors draw current in short peaks of high amplitude. Any filters' impedance will affect it.True. That's why you have to be careful when choosing a pwr. conditioner and find one that is non-current limiting. That's also why they usually affect the sonics of an amp.
The Blue Circle Thingee FX2 is "non-current limiting," and it lowered the noise floor in a big way for my components. However, when I plugged my high-current SS amp into it, there was a loss of detail and dynamics.
I think there are very few conditioners that can handle the current-draw of an amp.
There are some power cords that are so good at lowering the noise floor, that a conditioner probably isn't needed. But you have to pay for that quality, such as Synergistic Research and Audience.