Car Power Filter EMI Noise Ground Loop Isolator Suppressor for Auto Stereo Audio Radio Stereos Amplifier Amp Speaker Equalizer Subwoofer 12V

I don’t know how it works, but it does. I run a mini pre-amp thru my boat stereo to use with a CB style mic as an inexpensive PA system. (Guided sightseeing charter boat).New boat had a ton of line noise when the engine was running. So much, the PA was not usable. I ran the 12v supply for the stereo and pre-amp thru this isolator, and it greatly reduced the noise. There is still some noise, but it went from un-usable to useable.To be fair to the remaining line noise, I have to crank the radio volume to 33-35 so my guests can hear me. That’s pretty high, and I don’t fault this product for not removing 100% at the highest volume.Oh, like others have said, the wire insulation is ridiculously thick, but the wires are maybe 14 gauge, and appear tinned. The thick insulation only makes butt connectors really tight.

This absolutely works if installed correctly. Most of the Dual Electronics stereos have an alternator whine due to cheap or non-existent shielding within the radio itself. This is from my own personal experience with the brand. If your old car stereo did not have an alternator whine, and now it does, and you’re sure it the new stereo was installed correctly, it’s more than likely the build quality of the radio. To completely fix the whining noise, do the following: connect the Power Filter on the yellow, constant-hot (memory) wire between the vehicles harness and the car stereo. The “input” wire connects to the vehicle’s harness, the “output” wire connects to the stereo harness. Ground the black wire to a metal component attached to the vehicle’s frame. ZERO noise is now coming through my speakers when the truck is running. No noise on Bluetooth, AUX, radio, etc. Excellent product!

I have left very few negative reviews compared to the number of positives. That said: this thing does not work. I got no reduction in noise floor when it was installed. I do see where some have had decent results. This may mean I just got a bad unit. The build quality is not that great when I looked inside. The wire gauge is deceptive as well. In the photo this looks like 8 gauge but is actually closer to 14. As such; current handling capacity is limited.I would go with something different or order the parts and make your own. I am now in the process of either finding a better unit or homebrewing.

The thickness of the insulation is annoying as it makes cleanly adding a connector to it impossible. The internals are not great. Someone did a very poor job with the soldering inside. It also relies on the thickness of the insulation to keep the components from shorting out on the case.The good: it mostly works. As the title says it took away like 80% of the noise. It's not perfect but I have to turn the radio up so loud that if it was playing anything I would never hear the static over what was playing.Really dont like how cheaply it is made. Hope it lasts.

Couldn’t get rid of a loud whine/electrical noise coming through the speakers when turning on the bilge pump or nav lights in a boat. Tied this in to the electric for the radio and problem solved

I was having a very audible static noise in my boat, I replaced every cable, wire, etc I could think of with no luck. I didn’t want to isolate a battery to solely power the radio so opted to try this. The static is slightly down but not completely gone. Overall, it did quiet it down but didn’t fix my issue.

I can finally listen to my system without the annoying alternator whine! Installed in minutes and it works perfectly. Definitely worth the money and it's fits easily behind the dash. People aren't wrong about how thick the insulation is but it didn't hinder the installation in any way.

In fact i heard it more,wires were huge! Had to return product. Whatever it is it,was built well to not work