I own the AudioQuest 7000. I hear no hum. But I suppose if I stuck my ear on top of the unit, I could probably detect something. Noise heard thru the speakers? No way, BS.
All transformers will produce some noise. I guess it would depend on what you have the conditioner sitting on. A vibrating thin flexible shelve would probably be a bad idea.
The benefits of using the AudioQuest power conditioner is way larger than any type of noise issue you may perceive. And I have tried all of the big-name conditioners.
My 7000 powers not only my front end equipment but also 2 very large and powerful mono amps (Michi 8). The amps sound better and are more dynamic than just plugging them into the wall outlet! I think the AudioQuest circuitry is supposed to be able to store enough current for very large peak demands. Something like 90 amps!
BTW, Don’t believe Jay’ audio lab, he is typically full of it... All for show and probably for money.
ozzy