Do power conditioners help with unwanted hum/noise

It really depends on what the source of the hum/noise is. You need to define the problem before throwing money at it.

Kal

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.