Power everything

Very simply put, a pwr conditioner lowers AC line noise and EMF interference. Now that the noise level in your system is lower, you can hear more detail in the music. A conditioner will usually have a surge protector that will trip the circuit in case of a line spike in the way a circuit breaker works.

In areas where the power grid is especially dirty and unstable, a power regenerator is called for. Many of these units are still called Power conditioners depending on the manufacturer. This is an "active" unit where the AC line voltage is converted into a DC signal and processed into a clean sine wave equal to the correct voltage to run your system.
The first type of pwr conditioner I noted is a "passive" device; it is really acting more like a filter.

Downside of an Active Conditioner is the expense. So, you need to determine the conditions of where you live; dirty, noisy power line, power outages, lightning strikes.

Mucho info in the archives, here's one...

http://forum.audiogon.com/cgi-bin/fr.pl?hbest&1034192322&read&keyw&zzbest+power+conditioner

If you are looking into upgrading your power source, start with a dedicated AC line. It will greatly reduce noise and no more sharing the line with any appliances in the home.

That was a very concisly and well put answer, Lowrider.

02-01-15: Lowrider57
Very simply put, a pwr conditioner lowers AC line noise and EMF interference. Now that the noise level in your system is lower, you can hear more detail in the music.

I would like to disagree & would like to add that most passive power conditioners in the market substantially constrict the flow of current into amplifiers thereby sucking the life out of the music. When I was in the market I could not find a single passive power conditioner that I liked until I came upon the Richard Gray 400 unit. Then, too, I found it best for only my front end components where it has worked very well to this day.
Most passive line conditioners claim to have the filtering in parallel/shunt to the AC line & they very well might do so but somehow they suck out the life of the music. So, even tho the AC line noise might be lower, I personally found the music far from stimulating.

02-01-15: Lowrider57
Very simply put, a pwr conditioner lowers AC line noise and EMF interference. Now that the noise level in your system is lower, you can hear more detail in the music.

while passive line conditioners do have a surge protector, this surge protector does fall into the signal path & you can hear its adverse sonic effects. Further, the surge protector is designed to trip at some much higher voltage such as 300V so that it does not trip accidently during normal usage & during initial power up of the electronics. If the surge protector trips at 300V or something similar, your electronics will be fried long before that! So, that surge protector in the passive power conditioner is pretty useless.

I personally think that you have a few options
* dedicated lines like Lowrider57 already suggested
* isolation transformer which has a common-mode rejection in the 140dB region. These end up being Hospital-grade units. Expensive but worth it.
* AC regeneration for the front-end components & dedicated lines for the power amp(s). I don't think that an amp should be constricted thru a passive or active AC filter/regenerator - for the music to flow, the amp will need transient surges in current that a pssive or active line filter will curtail to the detriment of music enjoyment.
* Battery power for everything or for front-end. This is not practical for obvious reasons. I did hear one such system at the 2007 RMAF & it did sound really very good. The background was a darker shade of black; something i've rarely heard since. Re. practicality, I had only to look behind the equipment to see wood-veneer box after box of batteries powering everything - it was ridiculously impractical but sounded great! ;-)

My 2 cents worth.....

most passive power conditioners in the market substantially constrict the flow of current into amplifiers thereby sucking the life out of the music.

1. Agree. Amps will sound better when plugged into the wall. Some conditioners will lower the noise floor of an amp, but at the expense of imaging and dynamics for starters.

2. I started the Op off with the very basics in the concept of Power. Now we've moved on to the advanced class. That's OK.