I will ask a dumb question on power conditioners

Garebear, as you can see, your question's not so dumb.

There may be differences among some manufacturers using these terms

Bill_k says it best; power conditioner seems to be a blanket term which includes active and passive units. The active unit is a regenerator cleaning the AC line voltage by converting it to a DC sinewave and then outputting clean AC to the components. Passive uses capacitors and other proprietary electronics to remove dirty line noise and lower the noise floor.

In the Classifieds, the "AC Conditioners" listed are active and passive units, but are largely active units(regenerators).

Garebear, as you can see, your question's not so dumb.

There may be differences among some manufacturers using these terms

Bill_k says it best; power conditioner seems to be a blanket term which includes active and passive units. The active unit is a regenerator cleaning the AC line voltage by converting it to a DC sinewave and then outputting clean AC to the components. Passive uses capacitors and other proprietary electronics to remove dirty line noise and lower the noise floor.

In the Classifieds, the "AC Conditioners" listed are active and passive units, but are largely active units(regenerators).

Power distribution units have multiple outlets usually with some filtering incorporated.
That's my understanding of the different devices.

"DC sinewave " No such thing
It converts it to dc and then takes the dc and creates a sinewave

that's true. And then outputs clean AC. My bad.

Thank you as the original OP - what comapnies / brands would be a good place to start for pasive line conditioners ????