BOSS B25N Ground Loop Isolator and Noise Filter

BOSS B25N Ground Loop Isolator and Noise Filter

Brand:| Model: B25N
Ground loops create noticeable hum in home audio systems, and alternator whine (also known as engine noise) in car audio systems. Eliminate both with the BOSS B25N ground loop isolator.
  • Cancels irritating ground loops
  • Eliminate system hum in home audio systems
  • Remove alternator whine in car audio systems
Part # 
Weight: 0.37 lbs.  
List Price$12.99
You Save33%
Your Price
Part # 265-4041
Qty:  EA
Available Payment Methods

Product Details

BOSS B25N Ground Loop Isolator and Noise Filter

The BOSS B25N is designed to eliminate ground loop noise (usually referred to as hum) and alternator whine from two RCA line-level audio channels. Great for the car, and even for the home, where amplifiers and other electronics (such as crossovers and equalizers) are separate of the source. Built-on mounting tabs facilitate installation. Dimensions (L x W x H): 3.4" x 1.5" x 1.5".

BOSS B25N Ground Loop Isolator and Noise Filter
  • BrandBoss Audio Systems
  • ModelB25N
  • Part Number265-4041
  • UPC791489170055
  • Product CategoryNoise Filters
  • Unit of MeasureEA
  • Product Rating
    (4 Reviews)
  • Weight0.37 lbs.
  • California Prop 65

    Warning: California residents only. Please note per Proposition 65 that this product may contain chemicals known to the State of California to cause cancer and birth defects or other reproductive harm.

Similar Products

View similar products to the BOSS B25N Ground Loop Isolator and Noise Filter
in the Noise Filters product category.


BOSS B25N Ground Loop Isolator and Noise Filter
BOSS B25N Ground Loop Isolator and Noise Filter is rated 5.0 out of 5 by 4.
Rated 5 out of 5 by from Fixed my alternator whine!This was a very quick fix for my issue, which was loud alternator noise in my rear Kicker 6x9s driven with a Coustic 250C2. My front door speakers were driven by the head unit and they were quiet.I simply unplugged the trunk mounted amp RCAs and placed this device between the cable from the head unit and the amp inputs.I do want to the clarify that this is simply an isolation transformer which should be a 1:1 ratio and work bi-directionally. The directions on the back of the packaging illustrate the male pigtails as INPUT and the female pigtails as OUTPUT, which was the exact opposite of what I needed, and would have required a separate male to male jumper and two female bullet couples to change the genders, but trust me, that is not needed. My system sounds great now.
Date published: 2015-02-16
Rated 5 out of 5 by from Excellent serviceThe item I bought came very promptly and was of the quality I had hoped for. These folks seem to be above board and make a real effort to please their customers.
Date published: 2014-06-26
Rated 5 out of 5 by from works as advertisedNo complaints. Installed with new amp and worked great the first time even though the head unit was pretty close to the amp, and there were a few unavoidable wire cross overs.
Date published: 2014-06-09
Rated 5 out of 5 by from ware for your moneyReally nice product. Filters all the noises, with clear sound.
Date published: 2014-05-21
  • 2015-03-30T07:45CST
  • bvseo_cps, prod_bvrr, vn_cps_3.1.1
  • cp_1, bvpage1
  • co_hasreviews, tv_0, tr_4
  • loc_en_US, sid_265-4041, PRD, sort_mostRecent
  • clientName_PartsExpressInternational

Product Q&A

Get your questions answered from other customers
who own this product or have experience with it.
If your question requires design or troubleshooting information,
please email  for a prompt reply.
BOSS B25N Ground Loop Isolator and Noise Filter

I have an Amphony Model 200 amp I'm using with my computer.  When the computer is attached to the amp, but not outputting any sound, I get a buzz in the speakers (with no load attached, there is no buzz).  Would this device eliminate that buzz?

Asked by: Krowten
If the buzz goes away when you unplug the RCA's from the amp (or computer), you probably have a ground loop. This filter will help with that issue.
Answered by: MattP
Date published: 2015-01-16

I have an new surround sound  receiver/amp all in one that hums constantly.  I bought the Boss B25N but don't know how to install it.Do the male RCA jacks go  into the red/white input  jacks in use, or unused vacant jacks?  And what is the head unit?

Asked by: Tom Sr
This is designed to go between a source (CD player, DVD player, etc.) via line level RCA's and the receiver. If the receiver hums by itself with only power and speakers hooked up, this will not help you and the receiver is likely the problem.
Answered by: MattP
Date published: 2014-08-01
  • 2015-03-30T07:54CST
  • bvseo_cps, prod_bvqa, vn_cps_3.1.1
  • cp_1, bvpage1
  • co_hasquestionsanswers, tq_2
  • loc_en_US, sid_265-4041, PRD, sort_recentQuestionsFirst
  • clientName_PartsExpressInternational

Customer Projects

Customer projects that include: BOSS B25N Ground Loop Isolator and Noise Filter

If you built a project using this product, post it in the Parts Express Project Gallery.

Customer Discussions

If you would like to start a discussion about this product, post a thread in the TechTalk Customer Forum.

Recently Viewed Products

Get Deals
emailed to you every week.

Be the first to hear about new and exciting products,special pricing and incredible deals!

See This Week's "GET DEALS" Email
Parts Express
725 Pleasant Valley Dr.Springboro,OH 45066USA

© 1996-2015 Parts Express, All Rights Reserved

Live Chat Software