Parallel mains filter or purifier info needed !

[promitheus]

Hi to everybody,

I have read a lot of info about normal LC mains filters and their problems. I think a better solution is to use a parallel filter across the live and neutral.

What do you guys think about that?
How can that be calculated?

I have here one solution at this link:
http://www.tnt-audio.com/clinica/mains_e.html

Are there any other circuits out there?

[peranders]

I think you are unaware of WHAT you are going to remove. L's are required when you need more effective filtering than only C's.

[promitheus]

Yeah but L´s in series with current can effect the devices connected after.
for instance dynamic loss by amplifiers.

[DIAR]

Have you heard about Auricap tweak:

http://didnt.doit.wisc.edu/audio/CDP/cdp.html

And here's mine:

http://kotiweb.kotiportti.fi/audiovideo/DIY/auricap/


The idea is to install 2 Auricap capacitors (0.47 uF) between neutral and hot. Auricap has been the best cap for the job. X2 or caps like that won't do...

I couldn't find any Auricaps in Finland so I had to settle with Arcotronics high quality (and high priced) Metallized Polypropylene capacitors.

You will find more info at http://www.audioasylum.com/audio/tweaks/bbs.html

I don't believe that a well designed filter with chokes in it will decrease dynamics. As long as components are chosen carefully and the L kept low, there won't be any problems.

I'm going to build a kick *** filter but there's still a lot of designing to do. Here's an unfinished scheme :

[peranders]

Originally posted by promitheus
Yeah but L´s in series with current can effect the devices connected after.
for instance dynamic loss by amplifiers.

The thing with L's IS to smooth the currents! I think you are a bit wrong about the "dynamics" because this is dependant of the whole power supply.

The filters you are thinking about are made for > 1MHz but special filters can go from 100 kHz, or even lower.

[peranders]

Originally posted by DIAR
I'm going to build a kick *** filter but there's still a lot of designing to do.G]

Aren't your L's rather small? Normally you have 1 mH or more.

[promitheus]

For audio equipment the filters should start cutting from 200 Hz-1000 Hz. That means the inductors should be bigger the shoe boxes. 1 mH is nothing you need something like 100mH at 10-20 Ampreres if you don´t want the filters to effect power amps.

For small devices you can use a normal filter but the problem is to design a filter for the whole system.

[DIAR]

Don't take me as an experienced guru, I'm totally newbie with these devices. I have been designing this filter with a few finnish high end enthusiasts.

The whole idea is to keep the inductance very low. Here's a few PSpice simulation pics:







Can anybody give some advice how to proceed with this filter?

[DIAR]

By the way. This filter is designed for CDP and preamp. The values don't tell everything. I'm going to use iron powder toroids and other sophisticated components.

If the L is increased too much, the filter will limit current feed.

Here's another very popular filter design that can be bought from www.diycable.com if DIY is not an option:

http://www.geocities.com/jonrisch/surge.htm

http://mysite.verizon.net/vze22yzp/id11.html

[peranders]

Originally posted by promitheus
For audio equipment the filters should start cutting from 200 Hz-1000 Hz.

Are you really sure about that?