Do power conditioners help with unwanted hum/noise

Sometimes they can help. The most graphic illustration I can think of is that I used to have a pair of Martin Logan Prodigy speakers. They had a little blue "ML" logo that lit up on the front when a signal was present; if a signal was not present for a sufficient time, they would actually go into sort of a shutdown mode. But, the little blue lights were always on in my house. Until I got a power conditioner. As soon as I did that, the little blue lights went off. So, there was obvious some kind of line noise impacting the signal path.

Oh yeah, it sounded better too. ;)

Dedicated power line first then power conditioning.

Edesilva brings up some valid points, but i'm with Kal on this one. The effectiveness of the power line conditioning in terms of noise & hum will have to do with the source of the noise & hum. If you've got a ground loop, adding a PLC won't do much to cure that. At least, not in most cases. Sean
>

Again, I'm in agreement with Sean. Hum, from my experience, is not remedied by power conditioning. Dedicated lines first: absolutely! Then a good pc and you're on your way to electric nirvana. (oops, don't forget those power cords, as well. not easy to do inexpensively) Treat your electric as another fundemental component. peace, warren

In some cases, even dedicated circuits or power conditioners might not help. If the house power system is not grounded properly or there's excessive current in the neutral wiring (dimmers, fluorescents, computers, etc), or if strong external RFI/EMI is present (nearby radio towers, radar facilites, etc) then no power conditioner will help short of an isolation transformer. Power conditioners are not a cure-all; it's like saying all a wrecked car needs is a coat of wax.