Installation from pre-amp to power amp and the hum really disappeared.

After a malfunction in the car's radio CD, the engine noise and the sound from the electric window motor passed through the amplifier to such an intense degree that for about a month I didn't even open it to listen to music until I figured out what to do! THIS little filter that doesn't seem like much really eliminated all the interference! I might take away a star because it cut quite a bit of bass! Of course, I added a little extra bass from the settings and it came back one way or another! VFM as much as it gets! For a temporary solution, it's excellent

The noise has disappeared 90% worth it, I could hear the engine noise from the speakers and this anti-interference device did a great job, I highly recommend it

It may work in other cases, but in mine I didn't see any difference. I'm not giving a lower rating because it may work in other cases, I have a noise from my computer, I expected it to help but....

Guys, it works! It's incredible!
I connected it to the studio monitor speakers that I have, which are connected to the computer with a Soundblaster HD sound card.
I had a lot of interference in the speakers, even when I moved the mouse. Everything disappeared with the filter

It does what it promises. Both sides can be used as input and output or reversed, like in all similar filters, even those that are labeled IN and OUT (they have a transformer inside). The two directions have only a small difference in noise.

It does exactly what it says.
I put it on my PC, where I had a grounding issue, and all the parasites disappeared.

It seems to do the job, but I will come back after I increase the amplifier a bit. Very good job although it doesn't completely eliminate the parasites, but about 85%.