On 2006-07-10, Nick Gorham wrote:
John Phillips wrote:
If it's really a mains problem then the issue is what is the specific
problem?

- RF interference?
- Mains spikes?
- Under/over voltage?
- Harmonic distortion of the mains waveform?

One you have missed out (though it could be covered by the last) is DC
on the mains, I have found that that can alter during the day, and could
have an effect, if only causing any torroid in the supply to saturate.

Yes. Good point.

Having said that, I have dreadfull mains where I am (ceramics factory up
the lane), and my mains is far from a sine wave. I have measured
(mainly) odd harmonics in it, of up to 1% all the way past 10k

The trouble is that if you do need a good mains sine wave then I think
the only obvious solution (not that I'm well acquainted with the matter)
is to rectify and carefully invert. That's not a cheap solution.

As to if it effects the sound, I dont know, I dont think so, but it does
make some of my TX's buzz more than I like sometimes.

I imagine it will offset the transformer's magnetic cycle and reduce
its rating but I would need to ask an expert to be sure. I wonder if
there's a DC spec. for the UK mains?

The OP, could get a cheap mains tester from someone like Rapid, and
check if the supply is measurably different at night.

Yes. The trouble is that things sold as "mains contitioners" to the
hi-fi-buying public these days are by no means all the same. Until you
know what you need to deal with you can't tell what to do about it.

And again, I think good audio kit should deal with normal mains
aberrations so I suspect most people buying a "mains conditioner" are
getting no real advantage.

--
John Phillips