are all power conditioners noisy?

I use a Oneac that doesn't hum and have had Powervars that didn't hum at all. One thing to try is to tighten the transformer nut down some.

Silent power conditioners? Certainly. Audio Magic, Soundapplication, Hydra--to name but a few...

I use a Panamax Max 5500 ACRegenerator that uses a large transformer to decouple wall AC from AC provided to equipment... my ear has to be practically right up to the unit to hear any noise at all... and even then it's extremely low in volume.

24phun, sorry you had bad luck regarding your power conditioner. I use for my digital front end the Ensemble Duo Isolink and for the rest of my system Richard Grays Power Station, two of them in what's called a star cluster arrangement, with great results.

Total dead silence with the background noise floor gone with air around the players, more precise layering in the soundstage, more natural timbres, without any loss of dynamics or prat.

There are many power conditioners on the market, I auditioned about five different ones before finding what I wanted, so I would suggest you try to audition some new pieces to find what you are looking for.