IFI SPDIF iPurifier


Member of the Trade: Madrona Digital
Pros: It allows cable-less connection to the DAC
Cons: Provides no measurable improvement
Included switchmode supply actually reduces performance by inducing mains noise
I measured the iFi iPurifier S/PDIF with a number of DACs and sources of digital input from Audio Precision Analyzer to USB to S/PDIF bridges. In all cases there is either no improvement in performance or slight degradation.

Full set of measurements here: https://www.audiosciencereview.com/...i-ipurifier-s-pdif-digital-audio-filter.2189/

Here is an example of it driving the Emotiva DC-1 DAC:


As seen, there are new noise products in low frequencies and the rest of the distortion spikes are exaggerated a bit.

To be sure, if I induce jitter over S/PDIF cable, it will eliminate those:


But much of the jitter I measure in DACs these days is internally generated, not from input. Here is for example a $29 DAC:


The induced jitter spikes are eliminated but nothing is done about the horrible amount of jitter and noise products this DAC has.

For computer use, it is hard to recommend this product. An asynch USB interface is liable to produce better quality than using the iPurifier. See these measurements comparing the two: https://audiosciencereview.com/forum/index.php?threads/battle-of-s-pdif-vs-usb-which-is-better.1943/

Don't even think about using this with a high quality DAC. I tested the Exasound E32 and as expected, iPurifier made its response slightly worse, not better. Save your money and put it toward a good USB DAC and you will be golden. :)


100+ Head-Fier
Pros: Cost effective coaxial & optical digital source cleaner
Cons: Not for mobile use, adds extra wires & connector leads into your system
What does the SPDIF iPurifier do ?
The goal of the SPDIF iPurifier is to clean up the jitter & electrical noise in digital input so that the DAC will more accurately convert it to the music output that you listen to.
So what does it actually do ?
It re-clocks the digital audio signal, galvanically isolates the DAP from the DAC and uses a Femto clock to provide better timing of the bitstream, together with an ultra clean power source. It doesn't change the bit size though.
I was interested in trying it out because the SPDIF iPurifier works on coaxial & optical data which is what I use to feed by Chord Hugo most of the time rather than USB inputs. The unit is also a lot cheaper than the W4S Remedy Reclocker. In the circumstances, I contacted Ifi Audio and they let me try out one.
Product design and contents
The first thing that you notice when you open the box is the number of connectors and cables included. The second is how small the device itself actually is. It is beautifully put together (akin to Apple style packaging) and look & feels to be a quality designed and built product. You should be able to connect your DAP and DAC to the SPDIF iPurifier using one of the many connectors supplied but whilst there is an illustration showing the input and output sockets on the SPDIF iPurifier, they are no instructions as to what each connector does and I needed some help in getting the system to work when using the optical input. All in all it comes nicely packaged and definitely gives the impression of being a quality product.
It only runs off mains power, so despite the fact its size would be suitable for portable use, you are unable to do so. Once you get the hang of it, the unit is fairly simple to use. It has a coaxial input connection at one end from your digital source,
which doubles up as an optical input , since this can also read optical data using one of the connectors they supply. At the other end, it has a coaxial output connector. On the side of the unit you have an optical only output and another slot into which the power supply connector fits.
Sound improvements ??
I have now had it for three months. Does it make a difference ? The answer yes and in a good way, but how much depends on the medium you are listening to.
Using the SPDIF iPurifier between my Ibasso DX90 & Chord Hugo via coaxial input and then into my Fatman SET 202 Amplier and into Stereo Speakers, there was a noticeable improvement. Everything was brought into a sharper focus, the bass became deeper, the cymbals crisper and there was a general greater level of silk smoothness to the music. It had better shape and definition, and a bigger soundstage, which in turn meant better separation.
A couple of examples.
I was listening to After on Second Life Syndrome by the Polish prog band Riverside (great band by the way), and Mariusz Duda's whispered intro literally seemed to jump out into the room at me and all the other instruments were more clearly defined. Interestingly, it gave the impression of being louder than when not using the IFI Purifier, which I assume was due to the greater focus.
On Yes' Awaken, the music had an extra creamy silky smoothiness when listening to Wakeman's synthesisers. Alan White's percussion sounded crisper.
When using the SPDIF iPurifier into headphone whether into my Beyerdynamic T90s or Shure SE846s, I did not hear as noticeable a difference. It did seem to be more "musical" but the extent of the sharper focus that I could hear through stereo speakers was much less apparent.
This could be because in my opinion headphones aren't so good as speakers at determining instrument separation , image/focus or the 3D holographic soundstage of the music being listened to.
* Brings everything into a sharper focus
* With better shape, definition & clarity
* Increased separation and wider soundstage.
* 10% improvement
Although, Chord's Hugo is designed to be pretty much immune from jitter, the SPDIF iPurifier was able improve the sound by cleaning up the source through its re-clocking and galvanic isolation. Logically it would make even more difference with DACs where jitter is a bigger problem. At £145, it's the most competitive coaxial or optical "data cleaner" in the market. This is a hobby where users are looking for step by step improvements and certainly for the speaker set up, the SPDIF iPurifier noticeably delivers. For me it's a keeper.