In article , Laurence Payne
wrote:
Did you measure anything objectively with instruments? Anything at all?
Doesn't it ever cross your mind how remarkable it is that after the mains
current has travelled all those miles underground and overhead, the last
few feet can make such a difference? Are you sure you're really hearing
what you think you're hearing?

He's suggesting that a filtered power lead can reduce interference
from an adjacent computer. Not that it's improving the mains supply
as such.

Then why does he use language like this.....?

"I then switched the power cable on the amplifier to use the Isotek
cable. Immediately there was an improvement in dynamics, percussion in
particular had much more presence and depth".

What he seems to be talking about is a change in the sound quality. He
doesn't mention the sudden absence of "interference", nor what he thinks the
interference sounded like before the substitution.

Since he attributes the interference to the effects of switch-mode power
supplies in other equipment on the mains wiring, it would be interesting to
know if any of the audio equipment has this type of power supply, which I
believe is quite common. If so, is there a theory as to why the
"interference" only comes from a PC in the next room, but not from the audio
equipmenmt itself?

Rod.