---
product_id: 3459241
title: "B25N Noise Filter for Car Sound Systems - Ground Loop Isolator for Crossover Stereo Equalizer Amplifier Subwoofer"
brand: "boss audio systems"
price: "€ 28.90"
currency: EUR
in_stock: true
reviews_count: 8
category: "Boss Audio Systems"
url: https://www.desertcart.ie/products/3459241-b25n-noise-filter-for-car-sound-systems-ground-loop-isolator
store_origin: IE
region: Ireland
---

# Compact 3.4x1.5x1.5 inch design Eliminates high-pitched alternator whine Ground loop isolator tech B25N Noise Filter for Car Sound Systems - Ground Loop Isolator for Crossover Stereo Equalizer Amplifier Subwoofer

**Brand:** boss audio systems
**Price:** € 28.90
**Availability:** ✅ In Stock

## Summary

> 🔊 Clear your ride’s soundtrack—silence the noise, amplify the vibe!

## Quick Answers

- **What is this?** B25N Noise Filter for Car Sound Systems - Ground Loop Isolator for Crossover Stereo Equalizer Amplifier Subwoofer by boss audio systems
- **How much does it cost?** € 28.90 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.ie](https://www.desertcart.ie/products/3459241-b25n-noise-filter-for-car-sound-systems-ground-loop-isolator)

## Best For

- boss audio systems enthusiasts

## Why This Product

- Trusted boss audio systems brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Silence the Static:** Eradicates annoying alternator and electrical noise for crystal-clear sound.
- • **Audiophile-Approved:** Preserves full audio fidelity with zero signal loss—hear every detail.
- • **Drive with Confidence:** Trusted by car audio pros and home enthusiasts alike to banish buzz and hum.
- • **Plug & Play Simplicity:** Compact, lightweight design installs in minutes—no tech headaches required.
- • **Universal Compatibility:** Works seamlessly with crossovers, equalizers, amplifiers, and subwoofers.

## Overview

The BOSS Audio Systems B25N Noise Filter is a compact ground loop isolator designed to eliminate high-pitched alternator whine and electrical interference in car audio setups. Compatible with crossovers, equalizers, amplifiers, and subwoofers, it ensures pristine sound quality without signal loss. Lightweight and easy to install, this device is a must-have for audiophiles and professionals seeking flawless in-car audio performance.

## Description

desertcart.com: BOSS Audio Systems B25N Noise Filter for Car Sound Systems - Ground Loop Isolator for Crossover Stereo Equalizer Amplifier Subwoofer : Electronics

Review: Listening to music is probably my favorite hobby. I went through three different home built ... - Listening to music is probably my favorite hobby. I went through three different home built PC's (have been building my own systems for a while now) to get rid of noise emanating from these builds i.e. Home entertainment PC based systems. This little box cleared up the noise completely. It does exactly what is was designed to do, i.e. get rid of input noise. For more details read on. I'm a PC enthusiast with audiophile taste but not their pocket. My previous system was an Amd FX-6350 CPU and a Sound Blaster X-Fi Platinum sound card for a 5.1 sound system. Two power amplifiers and 15" and 12" speakers for sub's and front and other smaller speakers for rear and centre. My FX-6350 System had no noise problems but I was dissatisfied with it's performance. I messed up my system striving to extract more performance from it. The system froze during a bios upgrade ending my MOBO's life hence the need for my new build, an FX-9590 PC. I went for an upgrade of my sound card as well. The first new system an AMD FX-9590 with a sabertooth 990fx and an upgraded Soundblaster Z sound card was working well with the exception of noise coming from the sub-woofers and to a lesser degree from the front full range speakers connected to the pyramid PA-1800X and PA-800X power amplifiers respectively. The whining static like in and out white noise morhed with a high pitched sound of a few kilohertz was unbearable especially since my new sound card was rated @ 116db S/N ratio. I tried a different power supply and video card which helped a little but the noise was still there. Bought another MOBO but the thermals of that board was too low for my new 220w tpd processor, but worked well my FX-6350. I then sold the first MOBO the sabertooth 990fx which locked up on the boot screen. I thus gave up the second MOBO which according to my research had a few successful builds with a FX9590 CPU. I sold it along with the FX-6350. I'm now down three MOBO's I have a powerful new CPU and no working system. I then purchase my final MOBO a Crosshair V formula Z and guess what the noise is back. I researched the problem on-line and tried sheilding the sound card with foil and cardboard - no significant difference. With my MOBO bios one could save various bios setting profiles, so I underclocked the machine significantly from 5.0ghz to 1.5 or 1.8 ghz. It helped but noise was still there but more tolerable but the machine's performance was significantly diminished.. Frustrated with performance I went back up in clock speed and turned off two of the eight cores, it helped but not enough. I was convinced that the problem was processor based I had no intentions of buying another MOBO. SInce Sub-woofer output is mono I used two ten band equalizers in series i.e. channel into channel and then equalizer into equalizer and attenuated everything from 300 hz and above. total attenuation 12db per channel times 4 - 48db this yielded the largest reduction in noise and I used this system for a while but in a quiet room, anyone with a keen ear could still hear the faint noise. While searching for a better solution on-line I came across a number of possible solutions and one of them took me to a device similar to this one on desertcart. I reviewed the specs and especially the reviews of devices similar to this one and despite a few negative reviews after careful consideration I decided on this one. That is a decision I will not regret. My noise problem persisted for several months and could be detected in a room from a distance of twenty feet or more feet even with the volume muted on my PC. I tried a number of possible solutions which had limited to no success at all. I went through three different motherboard at a cost of a couple hundred dollars and guess what the solution was this device available right there on desertcart for less than 10 bucks. I highly recommend this product it works. I experienced no audible signal loss as some reviewers claimed but I did experience full noise loss. I think it was designed for car audio but it certainly works for home audio. Now I can put my ear to the grill of my 15's and hear no noise whatsoever with the PC soundcard volume at one hundred percent while nothing is playing. Thanks Boss audio for a great product.
Review: Works amazingly - These are amazing!!!! I have always liked BOSS products but I was skeptical of these when read the reviews. So let me give you short before the long. Buy them if you have static, buzz, or noise in your system. I installed a high quality sound system in my 1982 corvette. Bought all the harnesses and used retro sounds laguna beach radio. When I ran the rca cables to the amp I ran them up the center of the car as that’s the easiest and with a 40 year old car you want to avoid as many clips as possible. Well grounding on a 40 yr old fiberglass car is more difficult then you would think. So I grounded the radio through the factory harness with the applicable harness for my radio which is built specifically for this car. I also grounded the amp right to the battery as it’s located in the back right next to where I hid the amp. All sounded good until I started the car and got an abnormal buzz hum and just awful noise that would whine up with the rpm and would disappear after I had the radio at an ear blistering level. Well I was ready to try anything and found these. I didn’t think 2 $15 parts would fix my issue but figured “ hey if they don’t work I’ll return them and try something else” so I installed them today right after they got off the truck and before the desertcart drive could make it out of my driveway. These eliminated all the noise completely and took me 2 mins to hook up two sets. I installed them at the amp as I may be getting interference from other issues of running up the center of the car. But man does that system scream and what’s nice is I can listen at low volumes with out having to listen to that horrible buzz. I highly recommend these and if you read this review stop searching and just buy these. I will post a video of the difference once I have a chance.

## Features

- Reduces High Pitched Whine Alternator Noise caused by the car's electrical system
- Ground Loop Isolator Noise Filter
- Always Use High Quality RCA Cables for your Audio System
- Dimensions: 3.4 x 1.5 x 1.5, Unit Weight: .30 Lbs. Tips: Ground each amplifier independently. Same thing if you have added stiffening capacitors, go to a separate ground for the cap

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B000LP4RMG |
| Best Sellers Rank | #13 in Car Amplifier Noise Filters |
| Color | WHITE |
| Connectivity technologies | USB |
| Customer Reviews | 4.0 4.0 out of 5 stars (4,754) |
| Date First Available | May 10, 2008 |
| Department | CAR |
| Is Discontinued By Manufacturer | No |
| Item Weight | 4 ounces |
| Item model number | B25N |
| Manufacturer | BOSS Audio Systems |
| Other display features | Wireless |
| Product Dimensions | 3.38 x 1.5 x 1.5 inches |
| Whats in the box | BOSS Audio Systems Ground Loop Isolator B25N noise Filter for Car Audio Systems |

## Product Details

- **Color:** WHITE
- **Compatible Devices:** Receiver
- **Connector Type:** RCA
- **Item dimensions L x W x H:** 3.38 x 1.5 x 1.5 inches
- **Specific Uses For Product:** Car Audio & Video

## Images

![B25N Noise Filter for Car Sound Systems - Ground Loop Isolator for Crossover Stereo Equalizer Amplifier Subwoofer - Image 1](https://m.media-amazon.com/images/I/61TchapzvSL.jpg)

## Questions & Answers

**Q: can someone explane to me what this does as if i were a complete idiot?**
A: The ground isolator removes ground noise caused  by other components in the power system of your audio devices, it does this by decoupling the amplifier from the audio source directly, wires wrapped around in a transformer allow the audio signal to pass through induction but leave the ground isolated. So any noise on the ground line is not sent to the audio input of the amplifier.

**Q: Can I insert this filter between my power amp and preamp in my home audio system to fix the hum problem?**
A: Your hum problem is likely between your preamp and one of its inputs. Disconnect each in turn to see which is the problem. Use this there.
It breaks the earth loop. 

If you put it between the pre and power amp, the hum is already in the audio signal, so it would not be effective at that point.

**Q: Will this eliminate the buzz between my record player and receiver?**
A: You can usually eliminate hum between your record player and your phono stage input by grounding the two devices together with a dedicated wire, usually built-in to the record player, which attaches to a stud on the phono preamp or stereo. Hope this helps.

**Q: Will this work for a CB radio?**
A: sure, it filters out noise from the power wire

## Customer Reviews

### ⭐⭐⭐⭐⭐ Listening to music is probably my favorite hobby. I went through three different home built ...
*by W***E on August 8, 2016*

Listening to music is probably my favorite hobby. I went through three different home built PC's (have been building my own systems for a while now) to get rid of noise emanating from these builds i.e. Home entertainment PC based systems. This little box cleared up the noise completely. It does exactly what is was designed to do, i.e. get rid of input noise. For more details read on. I'm a PC enthusiast with audiophile taste but not their pocket. My previous system was an Amd FX-6350 CPU and a Sound Blaster X-Fi Platinum sound card for a 5.1 sound system. Two power amplifiers and 15" and 12" speakers for sub's and front and other smaller speakers for rear and centre. My FX-6350 System had no noise problems but I was dissatisfied with it's performance. I messed up my system striving to extract more performance from it. The system froze during a bios upgrade ending my MOBO's life hence the need for my new build, an FX-9590 PC. I went for an upgrade of my sound card as well. The first new system an AMD FX-9590 with a sabertooth 990fx and an upgraded Soundblaster Z sound card was working well with the exception of noise coming from the sub-woofers and to a lesser degree from the front full range speakers connected to the pyramid PA-1800X and PA-800X power amplifiers respectively. The whining static like in and out white noise morhed with a high pitched sound of a few kilohertz was unbearable especially since my new sound card was rated @ 116db S/N ratio. I tried a different power supply and video card which helped a little but the noise was still there. Bought another MOBO but the thermals of that board was too low for my new 220w tpd processor, but worked well my FX-6350. I then sold the first MOBO the sabertooth 990fx which locked up on the boot screen. I thus gave up the second MOBO which according to my research had a few successful builds with a FX9590 CPU. I sold it along with the FX-6350. I'm now down three MOBO's I have a powerful new CPU and no working system. I then purchase my final MOBO a Crosshair V formula Z and guess what the noise is back. I researched the problem on-line and tried sheilding the sound card with foil and cardboard - no significant difference. With my MOBO bios one could save various bios setting profiles, so I underclocked the machine significantly from 5.0ghz to 1.5 or 1.8 ghz. It helped but noise was still there but more tolerable but the machine's performance was significantly diminished.. Frustrated with performance I went back up in clock speed and turned off two of the eight cores, it helped but not enough. I was convinced that the problem was processor based I had no intentions of buying another MOBO. SInce Sub-woofer output is mono I used two ten band equalizers in series i.e. channel into channel and then equalizer into equalizer and attenuated everything from 300 hz and above. total attenuation 12db per channel times 4 - 48db this yielded the largest reduction in noise and I used this system for a while but in a quiet room, anyone with a keen ear could still hear the faint noise. While searching for a better solution on-line I came across a number of possible solutions and one of them took me to a device similar to this one on amazon. I reviewed the specs and especially the reviews of devices similar to this one and despite a few negative reviews after careful consideration I decided on this one. That is a decision I will not regret. My noise problem persisted for several months and could be detected in a room from a distance of twenty feet or more feet even with the volume muted on my PC. I tried a number of possible solutions which had limited to no success at all. I went through three different motherboard at a cost of a couple hundred dollars and guess what the solution was this device available right there on Amazon for less than 10 bucks. I highly recommend this product it works. I experienced no audible signal loss as some reviewers claimed but I did experience full noise loss. I think it was designed for car audio but it certainly works for home audio. Now I can put my ear to the grill of my 15's and hear no noise whatsoever with the PC soundcard volume at one hundred percent while nothing is playing. Thanks Boss audio for a great product.

### ⭐⭐⭐⭐⭐ Works amazingly
*by C***E on May 31, 2022*

These are amazing!!!! I have always liked BOSS products but I was skeptical of these when read the reviews. So let me give you short before the long. Buy them if you have static, buzz, or noise in your system. I installed a high quality sound system in my 1982 corvette. Bought all the harnesses and used retro sounds laguna beach radio. When I ran the rca cables to the amp I ran them up the center of the car as that’s the easiest and with a 40 year old car you want to avoid as many clips as possible. Well grounding on a 40 yr old fiberglass car is more difficult then you would think. So I grounded the radio through the factory harness with the applicable harness for my radio which is built specifically for this car. I also grounded the amp right to the battery as it’s located in the back right next to where I hid the amp. All sounded good until I started the car and got an abnormal buzz hum and just awful noise that would whine up with the rpm and would disappear after I had the radio at an ear blistering level. Well I was ready to try anything and found these. I didn’t think 2 $15 parts would fix my issue but figured “ hey if they don’t work I’ll return them and try something else” so I installed them today right after they got off the truck and before the Amazon drive could make it out of my driveway. These eliminated all the noise completely and took me 2 mins to hook up two sets. I installed them at the amp as I may be getting interference from other issues of running up the center of the car. But man does that system scream and what’s nice is I can listen at low volumes with out having to listen to that horrible buzz. I highly recommend these and if you read this review stop searching and just buy these. I will post a video of the difference once I have a chance.

### ⭐ Defective almost immidiately
*by O***6 on June 3, 2014*

I normally don't bash products but this one was horrible. I needed it to complete my amp install and it DID work as advertised... For about 10 minutes. As soon as I got everything hooked up and started tuning my amp I had issues. The two adjustment dials (left and right) are both very CHEAPLY made. I went to adjust the right one and as soon as I went to turn it (with a screwdriver) the right side cut out; The innards of the box had fallen apart. I fiddled with it (by using a screwdriver and tapping it) and got it to come back. A short trip down the road and the converter quite working again. I figured no problem so I swapped everything to the left side (I am only using one side of my stereo inputs and left the opposite side unhooked). The next day on my way to work it did it again. I got to work and fiddled with the left side this time and it came back. Now for today. I was on my way home and noticed my sub had cut out. I pulled over and tapped on the converter box with my knuckle and as soon as I touched it the sub came back on. From what I have seen the device is made very cheaply and not able to handle being touched once installed. If that is the case then it should be marked as such. I will be looking elsewhere for a replacement device in order to keep my stereo working.

## Frequently Bought Together

- BOSS Audio Systems Ground Loop Isolator B25N noise Filter for Car Audio Systems
- DteeDck RCA Splitter 1 Female to 2 Male, 2 Pack - RCA Audio Video Cable Splitter Adapter, Dark Blue
- Monoprice 1.5ft Premium 2 RCA Plug/2 RCA Plug M/M 22AWG Cable - Black

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*Product available on Desertcart Ireland*
*Store origin: IE*
*Last updated: 2026-02-22*