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American International S-25A

Power line noise filter

16 Reviews | 1 question - 6 answers

Item # 003S25A

This item is no longer available.

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Our take on the American International S-25A

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.

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

BigWes, Mckinney Texas

What's in the Box:

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

American International S-25A Reviews

Average Customer Review(s):

(16 Reviews)


BigWes from Mckinney Texas on 1/22/2015

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

surfin from Florida on 11/12/2014

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

Anonymous from Lauderhill, Fl on 9/17/2014

Crutchfield Customer Review (What's this?)

Great noise reducer

Pros: Easy installion

Cons: None

Solved my problem

Billy from Melbourne, Fl on 8/20/2014

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

2015wrx from Lake in the hills, IL on 8/19/2014

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 8/20/2014 We forwarded this review to our Technical Support team for follow-up. Lifetime tech support comes with every Crutchfield purchase.

Works perfectly

CRinPA from SE PA on 8/3/2014

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

Andrew from United States on 2/1/2014

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

johnA from seattle, wa on 12/16/2013

Crutchfield Customer Review (What's this?)

This helps to eliminate alternator whine in you electronics

Pros: fast delivery

Cons: none


Domingo from San Antonio, TX on 9/28/2013

Crutchfield Customer Review (What's this?)

Do the work



Noisy Radio

Ty from Hamilton OH on 5/27/2013

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

Ben S from Searcy, AR on 3/10/2013

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

Mark C. from Swanton, MD on 8/4/2012

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 8/7/2012 We forwarded this review to our Technical Support team for follow-up. Lifetime tech support comes with every Crutchfield purchase.

Really Good!

JimM from Idaho on 8/1/2012

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

Bake from Lexington, KY on 4/2/2012

Crutchfield Customer Review (What's this?)

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

Ben from Atlanta, GA on 11/13/2008

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

Philip from Huntington Beach, CA on 8/9/2008

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

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.

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Q & A

Customer Q&A

1 question already asked

I spend A LOT of time, research, and money before realizing that I needed to reground my amplifier. I thought I had a solid connection for my alpine amps (factory bolt hole in my ford F-150 where I had removed the tire jack). Turns out the bolt hole was a poor conductor. I wound up returning the sound filter before hooking it up I took my truck to ancar audio shop, they reground the amp and drilled several screws for my amp and capacitor ground. Everything worked (couldn't believe it). I was happy to know my equipment was not damaged. The fix cost a 100 bucks, but after all of my trouble it was well worth it. [ COLIN A  Jan 28, 2014 ]
Honestly I never used it. My problem ended up being one of my sets of rca cables. I had ruled them out after checking them with an ohmmeter. The alternator noise would come and go. I re-grounded my amps, added ground loop isolators, I already had my rca's ran on opposite sides of my truck, and was getting ready to install the noise filter. Decided to check the rca's again due to the intermediate noise and finally found the problem lying in one of the sets. I replaced the set of cables and have not had the problem since. What really had me convinced that I needed the filter was the noise came after I installed a new hi amp alternator and optima battery to handle the power draw from my amps. So I would strongly suggest double checking all of the above before ordering. You may still need the filter as I have used them in the past, but they were always my last resort. Hope this helps.Cory [ CORY  Jan 26, 2014 ]
thanks for the quick answer vance. john [ johnm  Jan 26, 2014 ]
Yes it did, I installed it in my 1984 Bronco. It had the same whine that increased with rpm, I found it eliminated all of it. I also bought the connectors they recommended and they made installation a breeze... Good luck [ VANCE  Jan 26, 2014 ]
Sorry John I did not install the S25A yet. [ NATHAN D  Jan 26, 2014 ]
Solved the problem for me. Whine occurred when an amp was added to my boat stereo system. I bought a second one for the second amp. [ GREG  Jan 26, 2014 ]