Mains Filters

[astral]

One of life's biggest mysteries is why the makers of fridges and A/Cs invent their own special form of Karaoke.

They like the sound of rifle shots and explosions added to music, but the rest of us probably prefer to prevent

mains interference from even having subtle effects on what we hear.

There are various off the shelf cables with built-in mains filters, but if you have some practical ability

you can build your own. Care is needed as you are dealing with lethal mains voltage, but the benefits

may be worthwhile.

I came across this site on the web.

http://www.audiomisc.co.uk/mains/filters1.html

Where I live there are frequent power cuts, so my Hi Fi and TV setup is run from a UPS.

Basically this is a large battery that supplies power via an inverter. At the same time the

battery is constantly being charged. This provides me with a good degree of isolation from

mains bound interference, but not from RF that may be picked up by the cable from the UPS

to the Hi Fi system.

[Nordlys]

Isn't an inverter considered a big noise source?

[astral]

I do not notice any noise, but my present setup is only mid-fi

I will see if I can borrow a scope to look at the waveform.

[Nordlys]

The idea sounds similar to what's called "regenerator" (shouldn't be confused with conditioner or filter). It converts AC to DC and DC back to AC. PS Audio used to sell a device like that (at price tag close to 100K baht!). Can you tell the difference as compared to when you plug the AC cable directly to the wall socket? Do you feel your system has lost dynamics after you started using UPS?

[CarlBkk]

That's why it's imperative to demo. It's a common side-effect of any filters and noise-reducing components whatever price to have a negative affect on the musical dynamics when plugged in. Ok, it may remove some fuzz but at the same time it takes something away (just like Dolby NR on cassettes...remember that?!). Some units profess not to have any effect on dynamics, but they still need to be tried with the variables (your particular system, your cables, your local electricity circuit).

[Nordlys]

It's a common side-effect of any filters and noise-reducing components whatever price to have a negative affect on the musical dynamics when plugged in. Ok, it may remove some fuzz but at the same time it takes something away (just like Dolby NR on cassettes...remember that?!).

Not the non-filter, non-current limiting type noise purification device like those, supposedly.

http://www.richardgrayspowercompany.com/products.aspx

http://www.quantumqrt.com/default.asp

http://www.psaudio.com/ps/products/descrip...les-accessories

When I inquired that Danish sales rep from Nordost who was demonstrating QRT's QX-4 about the use of QRT product in conjunction with my PS audio line conditioner (Duet), he flatly denied all line conditioners of any brand and recommended that I remove it from my system, claiming they're nothing but a compromise and whatever positive it creates isn't worth the negative side effects. I still think my system merits from it and I like how it sounds better with it than without. That said, my power amp AC cable goes straight into the wall outlet, with PS Audio Noise Harvester in the other socket.

[Saraquin]

Hi

Back in the day...rofl love that line, when i was fixin them tvs and vcrs etc line filters were common place our power was not soo good. I think all devices should carry their own filtering but its down to the coutry ya in, most have a emi standard to the effect of "does not emit interfence and will not be harmed by any it receives" blah blah.

Having any form of UPS, filtering, stabalizing on thai power can never be a stupid idea imho

Cheers