This is THE powercord I want :

Frap and Redkiwi, I came across something really interesting just the other day. My wife and I went to audition a Rowland Research 112. The gentleman who auditioned it for us was selling it so he could start a family. He had quite a setup but I was interested only in the 112. The amp sounded splendid in his setup and I saw quite a few good power cords sitting in a box and asked if we could listen again with a different PC. We did this a few times allowing for rewarming of the amp. There was very little discearnable difference between the PC's. Was my wife and I loosing it? I know I hear a difference with my amp at home. After a while we decided to make an offer on the amp which unfortunately was not high enough for the gentleman, so we went home. On the way home it really bothered me as to why there was no difference, then it hit me. The Rowland has a switching power supply. The AC from the wall is literally being regenerated. All the anti EMI and Noise stuff built into the PC goes out the window. If you have ever seen what feeds the rectifier half of a switcher on a scope, you would be suprised how clean the DC can become with a good filter like the Rowland has. The moral of the story is that not all is as it seems. If I had a conversation with this fellow before we auditioned the amp and he said there was no difference in power cords, I might have told him he was deaf and it was good he was selling his stuff. I just thank goodness I heard it first, kept my mouth shut and learned something.

Frank, I am not so sure. Certainly the recycled copper in the Taiwanese stuff you get at the cheap joints (here it would be Dick Smith Electronics, but there it is possibly Radio Shack?) does sound dirty. And I reckon the Harmonic Technology cables do benefit from the quality of conductor used. But geometry and dialectric are hugely important. Possibly even more so in PCs than in signal carrying wires. And I suspect geometry is the most important element in PCs, and dialectric the most important in interconnects and speaker cables. But this is just speculation from experimentation.

Liguy, you are probably right and it is a good point about a switching power supply, but as you described the situation it occurred to me to add that the differences in PCs may not be so readily discernible in an unfamiliar system. I think good PCs reduce noise and that this difference is not eliminated by most (perhaps all) power supplies. When you have these noise products constantly in your system and then they are reduced by a better PC, you recognise it as a "night and day" difference. I have found when helping people with their systems that I have been disappointed with the impact upgrading the PC appeared to me to have (compared with the impact in my system). But my alternative theory for this is that the impact of better PCs is much more obvious in a system where you have very good dedicated power feeds.

Redkiwi, I wholeheartly agree with you. Great point!