If I install '20A dedicated circuit'

Like most things "it depends!" Primarily on the quality of the AC supplied by your power company. Dedicated circuits cannot eliminate voltage fluctuations (not good for tube gear especially, because the bias current is affected), nor can they (without additional hardware at the panel) provide surge protection.

And if for some reason you wish to use balanced power for your front end stuff, you'll still need a balanced power unit.

Start by checking the wall voltage at different times of the day and night on weekdays and weekends. You can use a simple volt/ohm meter and record the readings. That should tell you. You certainly don't want the voltage to vary more than say, from 119 to 122 volts.

Once you

As others have said, it depends. In my weekend system, I have two dedicated 20A lines but they still vary in voltage more than I like. I use an AVR and filter.

Kal

That is not necessarily the case as someone mentioned it depends on the quality of power comming into your panel. I used a passive conditioner on and off for about 12 months. I did not like it, system sounded veilled, so I sold it and I plug my equipment directly into the wall. A dedicated circuit is still a good idea; I installed one but can't say I heard any real sonic benefits.

Chuck

I installed 3 dedicated 30 amp circuits 1 for each amp and one for the source componets. It is the best thing I ever did for my system. I don't use anything between my componets and the wall because I it would have to be all 10 gage wire and not restrict the current in anyway.

Mark