The American International S-25A noise filter helps eliminate noise that comes in through the 12-volt power line on your in-dash receiver or signal processor. Installation is simple. You have three wires to connect: one to the power line from the battery, one to the receiver's power line, and one to ground. The S-25A noise filter is recommended for audio components rated up to a total of 25 amps and 350 watts. Mounting hardware is included. Warranty: 30 days.

American International S-25A Reviews

Average Customer Review:

16 reviews
Review this product
Great Gear Giveaway

Submit a review and then enter to win a $350 rewards card


Review this product:

Thanks for taking the time to share your experiences about this product. Please be sure to focus your comments on the product itself. Read our Review Guidelines for more information.

Your email won't be visible. Please use the email address that is associated with your order.
(e.g., JohnD) Your review will be signed using the display name and location
(e.g., Charlottesville, VA)

Click on a star to rate the overall product on a scale of 1-5
1500 characters left
  Attach a YouTube Review
Crutchfield Video Review Guidelines
  • Only submit videos that you made or are authorized to use.
  • Do not submit videos that contain music, video or visuals that are copyrighted and belong to someone else.
  • Please see our Review Guidelines for more information.
500 characters left
500 characters left


Written By BigWes, Mckinney Texas on Thursday, January 22, 2015

Crutchfield Customer Review (What's this?)

Took care of noises comming through stereo on my motorcycle. Went from very little fm reception to crystal clear

Pros: Work as it says

Cons: No screw holes to mount it

worked for me too

Written By surfin, Florida on Wednesday, November 12, 2014

Crutchfield Customer Review (What's this?)

After going through the various checklists posted around the internet to try to eliminate alternator noise in my system, I determined that the noise was coming through the head unit and not the amp. Then I made sure the unit had a good ground and that the noise was not coming from the antenna or the speaker wires. I also tried wiring the unit directly to the battery and still had a high pitched whine that varied with the engine RPM. I installed this noise suppressor and it cured the problem. Easy to install and worth every penny!

Pros: works, easy to install

Cons: none

Noise Reduction

Written By Anonymous, Lauderhill, Fl on Wednesday, September 17, 2014

Crutchfield Customer Review (What's this?)

Great noise reducer

Pros: Easy installion

Cons: None

Solved my problem

Written By Billy, Melbourne, Fl on Wednesday, August 20, 2014

Crutchfield Customer Review (What's this?)

This worked great and solved my problem with my DVD player. I ordered 2 and 1 had a bad wire. The blue wire was not soldered correctly inside the unit. Crutchfield was awesome and quickly sent me a replacement. I noticed even on the replacement there was more movement on the blue wire than the others, but it still worked great. The unit is pretty big so it might take a little while to find a place to put it depending on you vehicle. I have a full size truck and it was not difficult to find a spot.

Pros: Works great and easy to install.

Cons: None

Ground noise suppressor

Written By 2015wrx, Lake in the hills, IL on Tuesday, August 19, 2014

Crutchfield Customer Review (What's this?)

I had a problem with noise in my vehicle that only showed its head with my amp gain turned up and my head unit set at zero volume. I attempted to solve the issue with this device to no avail. It sounds like my issue has rondo with the poor subaru factory headunit output. I'm sure this unit works but not in my case.

Pros: Inexpensive

Cons: Didn't work for me.

Crutchfield response on Wednesday, August 20, 2014 We forwarded this review to our Technical Support team for follow-up. Lifetime tech support comes with every Crutchfield purchase.

Works perfectly

Written By CRinPA, SE PA on Sunday, August 03, 2014

Crutchfield Customer Review (What's this?)

Works perfectly not only for car stereo applications also for 2 way radio applications to remove alternator noise from transmit audio.

Pros: fits perfectly-easy to install

Worked Perfectly

Written By Andrew, United States on Saturday, February 01, 2014

Crutchfield Customer Review (What's this?)

Exactly what I was hoping it would do. After I put in my new stereo, as I would drive I wouldhear a high winding sound coming from my alternator. I bought this with hopes that it would remove the high pitched whine and it did. Thank you.

Pros: Does what its intended to do

Cons: None at all

does exactly what it is supposed to do

Written By johnA, seattle, wa on Monday, December 16, 2013

Crutchfield Customer Review (What's this?)

This helps to eliminate alternator whine in you electronics

Pros: fast delivery

Cons: none


Written By Domingo, San Antonio, TX on Saturday, September 28, 2013

Crutchfield Customer Review (What's this?)

Do the work

Noisy Radio

Written By Ty, Hamilton OH on Monday, May 27, 2013

Crutchfield Customer Review (What's this?)

I can't complain due to the fact that I misdiagnosed the source of the noise. Turned out the radio was clean but my amp had developed a whine. Product was painless to install but can be bulky if you barely have room for the radio alone.

Pros: Easy install

Cons: Bulky if you're really scrapping for room behind the dash

Didn't help

Written By Ben S, Searcy, AR on Sunday, March 10, 2013

Crutchfield Customer Review (What's this?)

Crutchfield sent me this free because I ordered a Pac SNI-1 and it didn't help so they sent me this. I can't say anything bad as I didn't use it as I found out my Kenwood had a internal problem. But I can't say anything good about it either.

Save your money

Written By Mark C., Swanton, MD on Saturday, August 04, 2012

Crutchfield Customer Review (What's this?)

Absolutely worthless. Still hear engine noise plain same as before. Does not even lower the noise volume in the least into devices. JUNK!

Pros: None

Cons: Doesn't do what it is supposed to do... such as filter engine noise.

Crutchfield response on Tuesday, August 07, 2012 We forwarded this review to our Technical Support team for follow-up. Lifetime tech support comes with every Crutchfield purchase.

Really Good!

Written By JimM, Idaho on Wednesday, August 01, 2012

Crutchfield Customer Review (What's this?)

It totally eliminated the noise I was getting. I now have one for both vehicles.

Pros: It works as advertised. Not very big.

Cons: Short wires. Heavy. Hard to find a mounting location.

no real difference

Written By Bake, Lexington, KY on Monday, April 02, 2012

Probably not the product's fault, but this must not have been what my system needed because there is no discernible difference. So, just because your system has a high frequency whine that changes with engine speed, this may not be the answer. I coupled it with the PAC SNI-1 unit - and it apparently is not what my system needs (i.e., inexpensive Pioneer receiver, clarion 7-band equalizer, 4-channel amplifier, four 2-way 6.5" pioneer speakers in an old Corvette).

Pros: easy to hook-up

Cons: did not work for my system

It works...I guess

Written By Ben, Atlanta, GA on Thursday, November 13, 2008

Crutchfield Customer Review (What's this?)

This unit is a bit larger than I thought it would be, but I still found room under the crowded dash of my Jeep Grand Cherokee (wedged in between the radio area and the gauge console). As far as I can tell it's working. I suppose I'd buy it for another car if needed.

Easy Solution

Written By Philip, Huntington Beach, CA on Saturday, August 09, 2008

Crutchfield Customer Review (What's this?)

I'd been satisfied with Crutchfield purchases before and this time is no different. I had just put a new 383 small block with high performance ignition in my 1968 Camaro convertible and when I fired it up the first time I was thrilled how well the car ran but the audio system had the most horrible engine noise. A quick and easy 3 wire installation of this noise filter in the power wire to the head unit eliminated 90% of the noise. I bought 2 and installrd the second noise filter in the power wire to the amplifier in the trunk. Now all engine noise has been eliminated. Great piece of equipment...inexpensive and simple to install...took all of 15 minutes for each filter.

Hands-on research

What's in the box?

Download owner's manual

  • Noise filter (with attached 6" power/ground wires)
  • 7" Plastic mounting strap
  • 2 Flat head screws
  • Instructions

Product Research


Overview: This unit eliminates engine noise coming through the power source. Noise can also enter through the antenna, which is not handled by this unit but which requires an antenna noise filter. Since many vehicles have both problems they could require both this unit and an antenna noise filter.

Note:  For noise entering through the antenna, you should install an Antenna Noise Filter (see item # 003AS100).

Installation: To screw mount the unit, you first remove the mounting plate from the bottom of the unit (wiring instructions appear on the unit under the mounting plate). Secure the mounting plate using the supplied screws, and snap the noise filter onto the mounting plate. To use the strap mount, you snap the mounting plate (B side out) onto the unit's bottom, insert the included tie, and secure. The filter should be kept as close to the radio as possible.

Wiring: Black wire = Ground,  Blue wire = Positive,  Red wire = + 12 Volt.

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.