Hi,

"Serge Auckland" wrote in message
...

I think there is a point being missed he- Mains filtering won't
"make the audio sound better"

Agreed.

but it will remove impulsive interference like motor switching spikes
if any are present. If you do an A-B comparison before and after
installing any filtering, you *won't* hear any difference unless just
at the time you were doing the tests, the farmer next door switches
off his milking machine, or the spot-welder at the blacksmith down the
lane goes off.

My point was that my audio kit was happily doing it's thing on one ring
main,
while the electrician systematically turned on and off everything on
another
ring - fridges, chest freezers, sodium lights etc. They are on the same
distribution board. I didn't hear a thing, with or without filtering. No
fizzes,
crackles or pops, and no martians talking out of the left speaker. Maybe
I should thank Audiolab for a decent PSU :-)

BTW, next door does have a milking machine, about 500 yards away.
(really!) Power between here and there is overhead, passing about
15 meters from my house. The nearest GSM mast is 400 yards away
in the same direction. I never hear a thing coming out of my speakers
apart from music. The shed has it's own 10mm2 radial, which helps.

It wasn't always this way - I created a home made disco system
at the age of 15 that was home to several thousand earth loops,
bad grounds, mains hums and noise gremlins. I think I've heard
most of the noises that mains a.c. makes at 50Hz!

Closer to home, fridge compressors and central heating pumps can put
splats on the mains, and whilst I would always suggest suppression at
source, that might not be possible if the offending item is in your
neighbour's house, or the next flat.

Fortunately, my shed is in a big garden, surrounded by farms.
The nearest neighbours are black and white and taste good with
pepper sauce :-)

The avoidance of mains-borne clicks or equipment lock-ups is the main
function of domestic mains filtering. All other suggestions of
improvements in the sound are snake-oil, put about by those selling
expensive filtering items.

We agree. It should be done in the PSU, but if the difference in
price between a four way mains block without sensible filtering
and one that has it is a pound, I'd probably take a minute or two
to choose, because there are some really naff PSUs in the world,
just as there are some really naff mains filters in the world.

Regards,

Glenn.