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ifi iPurifier3 USB Filter Review

Rate this USB Filter/Tweak:

  • 1. Poor (headless panther)

    Votes: 61 40.9%
  • 2. Not terrible (postman panther)

    Votes: 60 40.3%
  • 3. Fine (happy panther)

    Votes: 15 10.1%
  • 4. Great (golfing panther)

    Votes: 13 8.7%

  • Total voters
    149

amirm

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This is a review and detailed measurements of the ifi iPurifier 3 "USB Audio and Data Signal Filter." It is on kind loan from a member and costs US $149.

iFi iPurifier3 USB Audio and Data Signal Filter Purifier Review.jpg

The iPurifier 3 comes in a gorgeous and nice to feel ceramic (?) enclosure. The enclosure give is enough weight to feel substantial but not too much as to strain the connector. It is an in-line device and comes with three useful adapters which should cover all your USB connection needs.

In case you are wondering what this is for, here are the company specs:
ifi iPurifier 3 Filter Specs.png


Think of it as a USB repeater of sorts. For the purpose of this review, I take for granted that it does all of the above. Question becomes if our audio DACs need such an upstream device to "clean" their USB connection.

ifi iPurifier3 Measurements
My favorite device for testing USB signal quality is a Schiit Modi 2 which in the past has show very high sensitivity to conditions of that signal. So much so that I could measure differences USB cables make when connecting to it! I started by measuring the DAC by itself using a 6 foot USB cable:

Schiit Modi 2 DAC Measurements.png


There was a ton of noise in the FFT spectrum with the noise floor jumping up and down every few seconds (no doubt due to activities in my PC). That in turn caused the SINAD to vary continuously between 84 and 91 dB. This variation is system specific and could be worse (or better) on other host computers.

Next I put in the iPurifier3 inline:

iFi iPurifier3 USB Audio and Data Signal Filter Purifier Schiit Modi 2 DAC Measurements.png


There was a significant reduction in the noise floor as show in FFT and power supply related spikes. There were still jumps but much less in amplitude. SINAD was now very stable. So clearly such filtering was good for the Modi 2.

One could stop here and think that this is a useful device. But such is not the case because any DAC with half decent design would isolate itself against USB vagaries. To show that, I grabbed the Schiit Modi 3+ which costs just $99 to test. Here it is by itself:

Schiit Modi 3 DAC Measurements.png


We see massive decrease in noise floor compared to Modi 2. Predictably, it doesn't need any help from iPurifier3:
iFi iPurifier3 USB Audio and Data Signal Filter Purifier Schiit Modi 3 DAC Measurements.png


I almost stopped here but noticed there was some increased spike toward end of the spectrum. I decided to run the Jitter test with and without iPurifier3:
iFi iPurifier3 USB Audio and Data Signal Filter Purifier Schiit Modi 3+ Jitter DAC Measurements.png


We see much increased spurious tones at 8 and 16 kHz. This corresponds to a jitter component of 4 kHz (12-4 and 12+4 kHz). I can't directly point to the cause of this but can guess that an extra inline device that uses power like iPurifier3 is going to degrade available current to the DAC. Fortunately the increased jitter rises up to only -120 dB which is below threshold of audibility -- again a sign of well designed product (Modi 3+ DAC).

Conclusions
It seems that the iPurifier does what it says it does: clean up the signal/power lines over USB and with it help devices that need it. Then again every DAC I recommend of which there are probably 50 to 100, already perform their own filtering and don't need any help. After all, I test them all on my desktop workstation without any such filters. Adding an active device to the USB connection can reduce available power and potentially decrease measured performance as show in the case of Schiit Modi 3+. Seeing how a better DAC costs less than iPurifier3 anyway, there is no reason to deploy such a device.

I can't recommend the ifi iPurifier3. Put your money toward a good DAC and sleep easy! :)

-----
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

musicforcities

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So disappointed neither Amir nor ifi itself noted THE MOST crucial aspect of this device: the ceramic case absorbs spurious vibrations induced by oscillating strings at the sub quantum level. The cryogenic process used further helps by aligning the ceramic structure, making its string energy absorption twice as effective. The extra jitter spikes are likely revealed by this filtering and are caused by disharmonious resonance with standard usb plugs of plastic or metal. …to fix those you need to replace the other usb cables with ifi audiophile usb with ceramic plug casings. For maximum clarity, you need to swap the internal chips out with ifi ceramic package chips, using only Cardas silver solder in the reflow process.

Hold on, I am having trouble due to my tongue being so distended into my cheek.
 
Last edited:

Ajax

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Hi Amir,

Thank you for your recent reviews exposing power cleaners, USB purifiers and exotic cables as unnecessary additions to our systems. This is important work and helps us appreciate those manufacturers that design their products well so that we are not in need of such nonsense.

I have recently installed an outside system on my patio consisting of Sonos connect (bit perfect and stable) feeding a Benchmark DAC 2 via optical out. The signal is then fed into a Buckeye NC252MP amp via balanced out which in turn drives a pair of B&W AM1 speakers. I have also connected a 12" Velodyne subwoofer to the RCA out of Benchmark and set the cross over at 70Hz.

Although the items (except the amp & speakers) were purchased used and are over 10 years old, the sound is crystal clear (stunning) at extremely high volumes, without the need for any peripheral gadgets. I learnt how to do this at a very reasonable cost (US$2k) from the information I gained from this site.

Thank you
 

alex-z

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Amir, would you be willing to test such devices in reverse?

In my experience, the pre-amp + ADC found in USB measurement mics are a lot more sensitive to power supply issues than a typical DAC. Admittedly this is a niche use case, but it might be a real one.
 

enricoclaudio

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Thanks @amirm for another revealing review. Coincidentally yesterday I was looking for an AC power adapter 12V/2A to recommend to a forum member who is having issues with his MiniDSP FLEX AC adapter and the first one that came up was an iFi for $109 (ouch)…. Of course, iFi claims their AC power adapters can improve the sound by cleaning and filtering whatever they are supposed to clean and filter
 

musicforcities

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Thanks @amirm for another revealing review. Coincidentally yesterday I was looking for an AC power adapter 12V/2A to recommend to a forum member who is having issues with his MiniDSP FLEX AC adapter and the first one that came up was an iFi for $109 (ouch)…. Of course, iFi claims their AC power adapters can improve the sound by cleaning and filtering whatever they are supposed to clean and filter
good god. Any decent adapter should work. get one that is safety certified. you could try one that uses a three prong (earthed) vs one designed for a two prong power plug if there is an issue in that regard.
 

enricoclaudio

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Thanks @amirm for another revealing review. Coincidentally yesterday I was looking for an AC power adapter 12V/2A to recommend to a forum member who is having issues with his MiniDSP FLEX AC adapter and the first one that came up was an iFi for $109 (ouch)…. Of course, iFi claims their AC power adapters can improve the sound by cleaning and filtering whatever they are supposed to clean and filter
good god. Any decent adapter should work. get one that is safety certified. you could try one that uses a three prong (earthed) vs one designed for a two prong power plug if there is an issue in that regard.
I did not recommend the iFi one of course. I told the guy to get one from MiniDSP for $10 ;)
 

voodooless

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@amirm, in what mode did you test the Modi 2? I bet it was in class 1.0 mode? Would be nice to test it in class 2.0 mode. Chances are that would already fix the jitter issues as well.
 

GWolfman

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Nice to see there’s some truth to their product. Too bad a proper DAC doesn’t need it, so no one should need to buy it. I’m fine with that.
 

DonR

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Solving a problem the rarely or no longer exists is better than solving one that doesn't exist. TBH, I was expecting less so well done.... I guess.
 
OP
amirm

amirm

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@amirm, in what mode did you test the Modi 2? I bet it was in class 1.0 mode? Would be nice to test it in class 2.0 mode. Chances are that would already fix the jitter issues as well.
I put it in the Enhanced/Advanced mode for these tests.
 

voodooless

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I put it in the Enhanced/Advanced mode for these tests.
That’s a bit surprising, but possibly the chip doesn’t implement asynchronous audio in Class 2.0 mode either…
 

FrantzM

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So disappointed neither Amir nor ifi itself noted THE MOST crucial aspect of this device: the ceramic case absorbs spurious vibrations induced by oscillating strings at the sub quantum level. The cryogenic process used further helps by aligning the ceramic structure, making its string energy absorption twice as effective. The extra jitter spikes are likely revealed by this filtering and are caused by disharmonious resonance with standard usb plugs of plastic or metal. …to fix those you need to replace the other usb cables with ifi audiophile usb with ceramic plug casings. For maximum clarity, you need to swap the internal chips out with ifi ceramic package chips, using only Cardas silver solder in the reflow process.

Hold on, I am having trouble due to my tongue being so distended into my cheek.
:D

Mods! Please move or, better, replicate this gem to the “ A Call for Humor” thread.

Peace
 

Koeitje

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I love how is shows improvement on the Modi 2, because that means it can be an improvement for bad DACs. Which means I can tell people for whom this does anything that "of course it works for you, it has been proven to improve performance of badly designed electronics". It's the ultimate Uno reverse card for the your-gear-isnt-good-enough-to-hear-it-crowd.
 

uwotm8

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Voted for great because a) suddently it... works b) even by the look I feel the upgrown musicality with that thing in use
 
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