If you can afford it dedicated power circuits for your rig with a seperate ground makes a huge difference. If your utility supplies noisy power a big honking isolation transformer is good too. The other alternative for noisy power is PS Audio Power Plants. I use all of the forementioned and it made a bigger difference than exotic powercords and given their cost not a significant difference in overall cost. However there are many different forms of electrical gremlins, utility service problems and wiring shortcomings. (Where I live I have them all.) Finding the best approach for your power conditioning needs is, as Carl says, not easy. There have been several discussions on audiogon of dedicated power approaches with an albertporter post, as usual, among the best.
Power cords makes difference-Why?
I just discovered to my amazment that even power cords swap with the same high-end brand of equipment makes a difference. My story follows , I would like someone to shed more light on the phenomenon.( I know there exist power cords costing thousands, but never bought in to it.)Recently I added a surround sound preamp (Classe SSP-50) and multi channel amp(classe CAV-150)and center and surround speakers(Dunlavy SC-1 and SC-II'S). I have two channel system consisting of Classe CDP.5, Preamp CP-45,Amp CA-400 and Dunlavy SC V's as main speakers.The power cord on the SSP-50 has a little larger dia then the preamp CP-45. Last few weeks I thought I was using 'better' power cord with the CP-45. Everything else remained same for two channel(SSP-50 isolated) and the sound stage changed for worse.I was scraching my head frustrated thinking if any thing else I did could change my Audio nirvana. Then I recalled the powercord swap and quickly changed back to thier respective cords and wallah: My original sound was back.So my question: What constitutes a great power cord? Thanks for your advice in advance.