[quote user="professorhat"]What annoys me is, the majority of people who say they can't do anything to improve the sound have never actually tried them. Fair play to fr0g, he admits he hasn't tried them, but won't dissuade you from doing a proper test yourself. Other forum members will actually attempt to ridicule you for doing this though, because they have all the scientific explanations as to why it won't make a difference, but more often than not, refuse to divulge this priviledged information to the masses...[/quote]
Really don't want to get sucked into all this again but just for the record, I have a seperate spur from my consumer unit to a dedicated, unswitched socket. This made no difference to the sound, that I could detect. I have tried different, esoteric, mains leads because they were offerred as a free trial. These were tested both before and after the dedicated spur was installed. Again, no discernable difference in sound quality, to my ears, on my system. I have also taken this a step further and tried an isolation transformer which again, made no discernable difference. Finally, I have even experimented using a massive inverter to supply 240v AC from a bank of 12v lead acid batteries. This supply was completely independent of the house mains. Again, no discerable difference.
One thing that did have an effect was a surge limiter which cured the "clicking" I used to get when the fridge came on and I would always recommend the use of some sort of surge protection. However, I cannot honestly say that my system sounded any better or worse with the surge limiter installed.
So, on the one hand, I have the results of my own experimentation and trials which show no discernable difference in sound quality. Together with this, there is the scientific explanation, which I have previously posted, which explains why any difference would be so small as to be undectable, if not immeasurably small. On the other hand, there are those who believe that mains leads will make a difference but the only evidence I have of this is purely anecdotal. There are no technical explanations or scientific evidence, including blind ABX testing, which could explain why mains leads might make a difference. My personal belief therefore, is that the reasons why some people believe that mains leads make a difference, must be psychological rather than technical.
This is my personal belief and I'm not trying to force this opinion on anyone.
To pre empt the likely responses to this post, let me just say that my equipment is sufficiently "high end" to benefit from anything which would show any subtly differences, and my own ears and those of my family and friends are also young enough.
So, on the one hand, I have personal experience of evaluating mains leads