ifi iPurifier3 USB Filter Review

[Dave Away]

I bought once an iFi micro power supply for my turntable SONY PSHX500, I actually did it for the silly reason to experiment if it was truth that a different power supply would change wow and flutter (measured by an iPhone of course). I did try ifi only because Amir tested a similar product and I was aware people more often use it for Raspberry Pi DACS in despite amir recommendation not to do that.
In the end I had to leave a 5 stars review on Amazon, I am still in doubt as it improved speed stability as I could measure a very marginal improvement that was obviously within margin of error of such an inaccurate meter, but it turns out the music output was louder without changing anything else.
The educated guess is that the ifi indeed reduce hum of the turntable and improve in a very clear way its performance.
In despite the no recommendation, there may be somebody who needs a product like that. I.E. owners of an old amplifier with good performance but subpar usb in.

Are we allow to compliment ifi for making products that do what they say?

 

[Srikanth]

Hi, i have been using ipurifier 3 with ifi zen dac v2 and very recently switched to Topping E70 DAC.
I use headphones with topping A90Discrete amp.
By looking at the jitter and noise performance of E70, I thought ipurifier 3 is not required because E70 measured already best on paper.So I thought of selling ipurifier 3.
But before listing for selling, just casually connected and seen ipurifier 3 with E70.
I was blown away with the improvement in sound quality. The difference is not 2% or 3%. Very noticeable improvement in the imaging, forward sound stage and especially the Bass quality and control.
I am lucky that i did not sell the ipurifier 3.
My new set up is E70+ A90D + Hifiman Edition Xs.
Without ipurifier 3, my new set up sounding great but, somewhere I felt some life is missing in the music. All these things are until i connected ipurifier 3 to the dac. It is a game changer.
I don't know if amir's measurements are correct or not. Otherwise may be he is not measuring the right things.
Measuring just SINAD, noise floor, Jitter is not enough because You can't measure the sound stage. You can't measure the imaging.
It is wrong to say that only low priced DACs get improved with ipurifier 3. Even mid to high level price DACs also greatly improved.
I did blind test. Anyone can do a blind test with this ipurifier 3 and the result would be unanimous. If you don't believe me, buy one ipurifier 3 to test and see and comeback and upvote my post.
I also seen that the improvement with topping A90D is far greater than improvement I noticed by changing my DAC to E70.

 

[Lexxie]

Claims:
Cleans noise (if needed), reduces jitter.

Test results:
Cleaned noise (if needed): PASSED.
Reduces DAC jitter during audio playback: UNTESTED

Conclusion:
Product not recommended.

...
Did I get something wrong or miss something?

 

[AaronJ]

Claims:
Cleans noise (if needed), reduces jitter.

Test results:
Cleaned noise (if needed): PASSED.
Reduces DAC jitter during audio playback: UNTESTED

Conclusion:
Product not recommended.

...
Did I get something wrong or miss something?

It's the (if needed) part that iFi omits in their literature. For less than the cost of the iFi device someone can purchase an entire DAC whose performance is so good that it doesn't need any help, and then also sell the old DAC.

 

[Lexxie]

whoa, nilly, i love the dance of objectivist vs subjectivist, but you don't get it both ways

"whose performance is so good" did you mean classically trained musicians or EE engineers whose wives left/leave/will leave ?

 

[Lexxie]

I am a previiously banned member of this forum and proud of it. No one and I mean NO ONE asks me about tone deaf vs color deaf, this is a ayatollah knows the truth kinda site where u pray toward meccah or get banned, ask me , i'll tell you if they let me, north america long ago lost the message and is banning/cancelling/censoring worse than anyone now. FOUTUS !

 

[BDWoody]

I am a previiously banned member of this forum and proud of it. No one and I mean NO ONE asks me about tone deaf vs color deaf, this is a ayatollah knows the truth kinda site where u pray toward meccah or get banned, ask me , i'll tell you if they let me, north america long ago lost the message and is banning/cancelling/censoring worse than anyone now. FOUTUS !

Ok, you've won.

You get to wear the badge.

 

[Ian Wendt]

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.

Long time listener, first time caller.

@amirm I purchased the SMSL M500 MkIII after reading the review of it that you posted. But it very much had an issue with USB power noise. Notable only when the GPU was under load, IE during gaming. When gaming, the noise would shift in pitch based on mouse movements. When the GPU was not being stressed, the noise would essentially go away. The issue was fixed by using an iFi USB Defender+ between the PC and the DAC. The same issue with a Fiio K7 was also resolved with using the USB Defender+. Neither DAC exhibited any noise via their respective headphone outputs, the noise was only present with the line-out and was not affected by pre-amp volume level either.
Perhaps there is a gap in the testing protocol?

 

[NickArcade]

Long time listener, first time caller.

@amirm I purchased the SMSL M500 MkIII after reading the review of it that you posted. But it very much had an issue with USB power noise. Notable only when the GPU was under load, IE during gaming. When gaming, the noise would shift in pitch based on mouse movements. When the GPU was not being stressed, the noise would essentially go away. The issue was fixed by using an iFi USB Defender+ between the PC and the DAC. The same issue with a Fiio K7 was also resolved with using the USB Defender+. Neither DAC exhibited any noise via their respective headphone outputs, the noise was only present with the line-out and was not affected by pre-amp volume level either.
Perhaps there is a gap in the testing protocol?

What does this have to do with the iFi iPurifier 3?

 

[Ian Wendt]

What does this have to do with the iFi iPurifier 3?

I brought it up because in this thread and elsewhere on this forum, Amir and others have repeatedly stated that a well-designed DAC will already filter power/be galvanically isolated, and devices like the Purifier and others are not necessary. Considering that the M500 MkIII received a glowing recommendation, it seems reasonable to assume that it too falls under the category of "well-designed DACs", but there seems to nonetheless still be potential for noise issues, which in my case was fixed by introducing a USB galvanic isolator.

 

[Lambda]

, Amir and others have repeatedly stated that a well-designed DAC will already filter power/be galvanically isolated, and devices like the Purifier and others are not necessary.

It Would be grade it ASR would actually test this...
I Totally agree a well-designed DAC would have not transmit noise from its inputs to its outputs. It don’t necessarily need to have "real galvanical" isolation. Functional isolation and filtering is fine.

But it its not tested and DACs are only rated and listen by the (over 120db) totally meaningless 1khz SINA performance
Manufactures will optimize for this and neglect things that have way more real world impact then the difference between 119 and 123dB SINAD

Everyone makes fun about PS audio and there Power optimizes...
But Topping selling USB isolators as add-on instead of integrating them in DACs.

 

[voodooless]

But it its not tested and DACs are only rated and listen by the (over 120db) totally meaningless 1khz SINA performance

I doubt anyone is listening at 1 kHz tones, nor is there only a single graph in the reviews to evaluate performance. If there is noise, the 1 kHz dashboard will show that just fine. Regardless, can you point to the DACs in the top category ordered by SINAD that shows other issues and is therefore not recommended?

 

[Purité Audio]

It Would be grade it ASR would actually test this...
I Totally agree a well-designed DAC would have not transmit noise from its inputs to its outputs. It don’t necessarily need to have "real galvanical" isolation. Functional isolation and filtering is fine.

But it its not tested and DACs are only rated and listen by the (over 120db) totally meaningless 1khz SINA performance
Manufactures will optimize for this and neglect things that have way more real world impact then the difference between 119 and 123dB SINAD

Everyone makes fun about PS audio and there Power optimizes...
But Topping selling USB isolators as add-on instead of integrating them in DACs.

I have found that generally manufacturers will sell anything if they think there is a market for it,
Keith

 

[Lambda]

can you point to the DACs in the top category ordered by SINAD that shows other issues and is therefore not recommended?

Considering that the M500 MkIII received a glowing recommendation, it seems reasonable to assume that it too falls under the category of "well-designed DACs", but there seems to nonetheless still be potential for noise issues, which in my case was fixed by introducing a USB galvanic isolator.

The DACs are not tested with common mode noise / current on the USB port.
But in the Real world it is inevitable to have some.

The Audio Precision Audio Analyzer has Extremely good CMRR and Functionally isolated inputs. so no Common mode currents.
AMPs on ASR don’t get tested for there input CMRR but in gneral CMRR will be lower then from the AP.

A low SINAD values manes the DAC is bad.
but a high SINAD value don’t automaticly means the DAC is any good.

If there is noise, the 1 kHz dashboard will show that just fine.

No. Only If you test for noise by injecting it... and only if you test with a realistic reviving device with realistic real world CMRR, real world realistic impedances (including some mismatch)

 

[voodooless]

The DACs are not tested with common mode noise / current on the USB port.
But in the Real world it is inevitable to have some.

Well, come up with a hypothesis and test setup and I’m sure someone would be willing to do some testing if it makes sense.

 

[Lambda]

Well, come up with a hypothesis and test setup

hypothesis for what? it’s all well understood.
CMRR, DM, CM, Measurements are common practice in EMI/EMC testing.

 

[voodooless]

hypothesis for what? it’s all well understood.
CMRR, DM, CM, Measurements are common practice in EMI/EMC testing.

It’s not about the things existing, it’s about what they supposedly do to the sound.

 

[Ian Wendt]

It’s not about the things existing, it’s about what they supposedly do to the sound.

For my particular issue, the noise was GPU noise, changing in pitch and volume with GPU load. It was extremely audible, but only if the GPU was actively being used for hardware accelerated actions. Video, games, etc. If I never gamed, the issue may well have gone unnoticed.

 

[Lambda]

It’s not about the things existing, it’s about what they supposedly do to the sound.

This is also well understood. it adds noise.

The Problem Ian Wendt had is very typical and common.
For most system this is below the audible threshold.
But still way over the ~-120dB noise floor from a SOTA DAC.

This is Why DAC SINAD is insignificant (if over 120dB) if the DAC passes noise from the CPU/GPU or other common mode current at -60dB compared to listening level.

 

[voodooless]

This is also well understood. it adds noise.

Yes, it is. But if we want to have this properly tested, we need a proper test protocol, and that's what this should be about.

This is Why DAC SINAD is insignificant (if over 120dB) if the DAC passes noise from the CPU/GPU or other common mode current at -60dB compared to listening level.

Yes, I agree that if you have ground loops, you can have noise issues, and if you have them, they are more annoying than any SINAD issue a DAC might have.