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Isolate Me From Noise – iFi iDefender Plus

Isolate Me From Noise – iFi iDefender Plus

iFi iDefender Plus is a Power Tweak or rather a USB Filter designed to remove buzz, hum and other noise caused by a bad grounding and grounding loops in your listening chain. It ain’t perfect for sure, and for some systems it won’t do anything, so today we’ll be exploring where it works, where it doesn’t and if I actually recommend it. We also included comparisons with Plixir BAC400, ifi iPurifier, and iFi AC iPurifier



iFi is huge as a company, but now with Brexit taking place, no one is sure how things will proceed. All we know is that they are still available on Amazon, and other stores, and that even during this time of crisis, they will manage to pull through somehow. They have always been out there for us music lovers, and from what I know, they aren’t going to give us up now. 

It should be noted that I have absolutely no affiliation with iFi. I’d like to thank iFi for providing the sample for this review. Every opinion expressed is mine and I stand by it, the purpose of this review is to help those interested in iFi iDefender+ find their next music companion. 


Product Link

You can get iFi iDefender+ from www.amazon.com here: https://www.amazon.com/iFi-iDefender/dp/B08G5CSRXW



First things first, let’s get the packaging out of the way:

The unboxing experience is the same as it was with the iPurifier 3.0, the iDefender is not a very fancy product, but it still comes with a cool package. 

Different from the iPurifier, it comes with a power adapter because it strips the USB post you’re connect it to from its power, and if you will connect a DAC/AMP that needs power, you’ll need to also provide power to it. Since the plug for the input power is in Type-C, you can use a Battery which is the most silent type of power out there.  


Video Review


Build Quality/Aesthetics/Functionality

You know I’ve been waiting a bit before posting this video when you see that my Youtube Video review is one of the most viewed out there about this unit. 

The device looks like a thicker, more modern-looking USB stick, it has a male USB plug (they have a version in type-C too), and a USB plug type A for you to connect your DAC to. 

Normally, I would not recommend the type-C version at all, there are very few devices that could be noisy over type-c, but then I remember that it is not meant for smartphones, but for laptops and computers with a type-C USB port. 

The power input is also in type-c, because iDefender strips the signal off its power, basically leaving only the signal in. To use it, you need to plug in a battery or silent power source that has a 5V / 2.5A to provide clean power. This is not necessary for every DAC out there, but it is a must for those that power from the USB port, like all of the ultraportable ones. Earmen TR-AMP is an example that won’t need the input filled. 

The whole point of the iDefender is to remove hum, noise, and provide a cleaner output. At least on paper, it is supposed to disconnect the computer earth. Good thing it is compatible with USB 3.0 too. 


Sound Quality

I should start by saying that it won’t work for everyone. In fact, this review is more about where it doesn’t work than where it does work, because you really need to have a hum / buzzing from your source for it to have what to remove. Judging from the Amazon.com reviews, it looks like a lot of people connected it to a Scarlett 2i2 to work, but unfortunately I went with the Audient Evo 4 series instead for an interface. That didn’t work for me so well, but I’ll post a video review on youtube about it really soon. 

For me personally, it did work with a few DACs. It is mainly made for DACs or portable DAC/AMPs, and it did work for ones, but ironically, not for entry-level ones. One that comes to mind is the Mytek Brooklyn DAC+, where I always had a noise going on in the background over the USB connection and it always bugged me. Wth the iDefender+, I could hear that buzzing / noise going away, and I could hear my music clearer, with better dynamics and a better overall clarity. 

Where the original iFi iPurifier made a change to a larger number of setups, the iDefender works in more specific scenarios. I never had a very good computer setup, but after testing it with my girlfriend’s laptop, I noticed that the iDefender has a larger effect with laptops. It removed some of the noise when I tried to use a Centrance DACport HD, giving a clearer sound. I didn’t notice the noise to begin with, but I noticed it while doing an ABX.

I couldn’t notice any change when using it with DAPs like iBasso DX220 MAX or FiiO M11 PRO, but connecting it to TA10 from xDuoo helped a bit as well. The results are way too variable and depend on what your chain is made of, how noisy your computer / laptop was to begin with, so please take everything with a grain of salt and consider it a bit of an experiment. I can’t promise it will work for everything, but where it works, it works and you’ll notice a background noise going away, letting you focus more on your music and having more fun in the process. 



Given its job, and that I never reviewed anything similar, that would introduce a grounding in a system where it wasn’t present, I picked a few other power tweaks to compare the iDefender+ to.

Among those is iFi’s own iPurifier 3.0, Plixir BAC400, and iFi’s AC iPurifier

iFi iDefender Plus vs iFi iPurifier 3.0 (75 USD vs 75 USD) – The two USB filters do two different jobs, and you can even stack them on top of each other to get a better sonic experience. Where I never had the iDefender make the sound much worse, iPurifier’s filtering can be a bit aggressive. With the iDefender+, the results are much more stable, and when a system had a grounding issue, it will clear it out. With the iPurifier, it is more of a matter of subjective testing. Where I can actually vouch for the iDefender+ solving issues if you had a grounding loop, I can’t vouch as much for the iPurifier actually doing a result that’s measurable or statistically clear. 

iFi iDefender Plus vs Plixir BAC400 (75 USD vs 1500 USD) – Plixir BAC400 is a totally different thing, and works for a different type of system. I want to attack the subject because there’s very little material online on what each type of power tweak does, so let’s start by saying that the iDefender+ simply defends you from grounding loops. BAC400 is a power conditioner that takes care of random power fluctuations on your power line. BAC400 becomes more efficient the more dirty your power line is, and works for all types of audio devices, like DACs, Headphone Amplifiers, Transports, Bluetooth Receivers, etc.

As long as you don’t need to draw more power than BAC400 can supply, it will help most systems out there, and power conditioners are far more versatile and universal than a grounding loop defender. BAC400 also works by improving the current, making things better for your system, and also protecting it from surges, where iDefender+ mainly protects you from ground loops. 

iFi iDefender Plus vs AC iPurifier (75 USD vs 100 USD) – AC iPurifier does something closer to what the Plixir does, but has something to do with grounding loops as well. It mainly can solve things when the grounding is not connected correctly to your power outlet, and it can also offer an extra layer of surge protection. You will know if you don’t have a grounding or if it doesn’t work well, if, when placing your hand on your computer or metallic devices, you will feel a tingling. This happened to me with older laptops, and the AC iPurifier seemed to help. For Audio, it is as contextual as the USB iPurifier, for some it will work, while for other systems it won’t do much. 


Value and Conclusion

The value of the iDefender is actually excellent. The point of it is that you can pay just 50 USD and heavily improve your system, if the issue was solvable with an iDefender. Since this type of issue can happen with really expensive setups, getting rid of the background hum can be really cheap if using it, so I totally consider it to be worth the asking price. 

The package is not overly interesting, but it comes with an adapter to connect an external power supply to its Type-C input, and it comes with all the manuals for it. 

The build quality is ok, it is a plastic USB stick looking device that goes between your computer / laptop and your DAC. It doesn’t get hot, it doesn’t have any kind of issues and it never made the sound worse for any setup I tried it in, so overall I could say I am happy with its performance. 

The sound quality with it will be variable, and ultimately if you’re looking for a solution for your grounding issues, I totally recommend the iFi iDefender+, but it is not a one solution fits all, and wether it works for you or not will vary a lot with the issue you were having. As long as your problem was with the grounding of your system, and as long as you had a grounding loop that was causing the hum, there’s no device that I tested so far that I could recommend more than the iFi iDefender+


Product Link

You can get iFi iDefender+ from www.amazon.com here: https://www.amazon.com/iFi-iDefender/dp/B08G5CSRXW

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Full Playlist used for this review

We listened to more songs than those named in this playlist, but those are excellent for identifying a sonic signature.  I recommend trying most of the songs from this playlist, especially if you’re searching for new music! The playlists are different for Spotify, Tidal and Youtube, and based on the songs I enjoy and are available on each!




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  1. Andy

    Beneficial advice. Many thanks!

  2. Charleslix

    You stated this wonderfully.

  3. Vedeline Dayik
    Vedeline Dayik

    Them Chinese products hit again 🙂

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