Months ago, I saw a filter power supply in a shop. The salesman told me that it's

a filter power supply, actually I don't know what it is. It just like a common

electrical outlet or a receptacle. But the sound seems different when the

amplifier connect to it. Is anybody know this power supply?

If it looked similar to a normal duplex receptacle but had a green dot on the face it was a medical grade outlet, also known as hospital grade. Otherwise it could be any variety of in wall power conditioning or filtering outlet from companies such as Panamax/Furman. Why don't you just call up the shop you were at and inquire?

The shop is not there now. Besides, I'm used to searching on the internet when I'm interesting in one thing.
I found yakars power processor looks like the one I saw, it's different from the Furman and PS Audio.
[Link: psaudio.com]
http://www.yakars.com/
No matter what is it, I don't its principle.

I swear by the MIT line of power filters.
[Link: mitcables.com]

I'll second the MIT and the Furmans. To use behind a flat panel I would suggest:

[Link: mitcables.com]

or

[Link: furmansound.com]

i can not open it

I can.

lipinzy,
It is hard to get help when you have a problem with an old discussion. This discussion had no input for more than 13 months. The people who posted in early 2009 probably don't care about this situation any more.

Also, when you say

it is good to say what "it" means. Remember that we don't all start with the same language, so one must often use simpler words and be sure not to say "it" without being sure we all know what "it" is. The humor of the answer from anyhomeneeds is that you were not being clear, he is not being clear, so you have an answer that fits your statement!