American International S-25A

Power line noise filter

  • American International S-25A


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Our take on the American International S-25A

by Buck Pomerantz

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.

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What's in the box?

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

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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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American International S-25A Reviews

Average Customer Review:

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5 out of 5

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.
Does what its intended to do
None at all
1 out of 1 people found this helpful
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5 out of 5

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
fast delivery
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5 out of 5


Written By Domingo, San Antonio, TX on Saturday, September 28, 2013
Crutchfield Customer Review (What's this?)
Do the work
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5 out of 5

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.
Easy install
Bulky if you're really scrapping for room behind the dash
1 out of 1 people found this helpful
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3 out of 5

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.
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1 out of 5

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!
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.
3 out of 5 people found this helpful
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4 out of 5

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.
It works as advertised. Not very big.
Short wires. Heavy. Hard to find a mounting location.
2 out of 2 people found this helpful
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2 out of 5

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).
easy to hook-up
did not work for my system
3 out of 3 people found this helpful
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4 out of 5

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.
2 out of 5 people found this helpful
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4 out of 5

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.
13 out of 13 people found this helpful
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1 question already asked

did this eliminate alternator noise thru the stereo speakers? i have a whine emitting from my speakers that gets louder and higher pitched when accelerating the engine. thanks- [ johnm  Jan 26, 2014 ]
6 answers
  • 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 ]

For a more in-depth review and enhanced detailed information on the American International S-25A, please visit the Crutchfield website product page (/ISEO-rccbcspd/p_003S25A/American-International-S-25A.html ).