iFi S/PDIF iPurifier: entry-level pricing, next-level results


“The Google Chromecast Audio is very easy to install, easy to use, very affordable and yet, wasted money as far as I’m concerned.” That’s The Netherlands’ Hans Beekhuyzen hitting us right between the eyes with his take on Google’s audio streaming puck.

Beekhuyzen continues: “I know that ‘quality audio’ is a poorly defined qualification, that’s why I use my three reference sets. Already on my €900 set 3 the Chromecast Audio performed so poorly, both analogue and digital out, that there was no point in going to Set 2. The stereo image is completely squeezed together, instruments are no longer separate entities, it’s just one mash of sound.”

Looking past an absence of gapless playback with Tidal and, to a lesser extent, Spotify, Beekhuyzen’s findings jive with my own. In all but the most basic of audio systems, the Google Chromecast Audio’s (GCA) optical output gets found out. The presentation lacks soundstage height, its bass definition is woolly and there’s clear evidence of top-to-bottom layer congeal. Mash potato, anyone?

One might then point to the GCA’s US$35 price tag and ask “Where’s the beef?”. Answer: it’s a close-to-free lunch that isn’t.

Of course, not everyone will necessarily hear it this way. As Chris Connaker wryly opined over at Computer Audiophile, “People who believe bits are bits and all digital audio must sound the same will be incredibly pleased with the Chromecast Audio.”

If that’s you, time to alight here.

A reader then stopped by DAR’s comments section to ask: “Are you saying that the GCA’s DIGITAL output has a “sound”? Or that it alters teh [sic] sound vs another digital output? What aspect of the TOSlink output do you feel is degrading the sound. It’s a direct digital connection to the DAC.”

Indeed it is. I restated my observation that the GCA lacks separation and clearly defined spatial cues, implying (once again) that digital audio isn’t just a matter of ones and zeroes. They represent the beginning of the digital audio story, not the end.

“But the connected DAC for the most part determines the sound yes? Do you suspect it’s jitter on the part of the CCA’s digital output perhaps?”, countered the reader.



Jitter – the mis-timed arrival of those ones and zeroes – which may or may not be caused/compounded by electrical noise. The GCA is powered by a switch-mode wall-wart that makes no claim of the quiet life.

Think that the galvanic isolation of TOSLINK is the answer. Think again. The way many a digital audio engineer tells it, electrical noise and/or jitter can blur the square wave to such an extent that the DAC’s receiver chip triggers additional layers of error-checking circuitry which then introduce more noise to the DAC’s sensitive internals causing disturbance to its super-sensitive clock and therefore more jitter.

Whatever the theory, many a DAC manufacturer’s marketing department would have us believe that their J-word. Experience tells us otherwise. All other things (DACs) being equal and with a sufficiently resolving system, no two digital streamers perform / sound alike.

For the aforementioned reader, for Hans Beekhuyzen and for yours truly, one freshly minted solution to the GCA’s lacklustre performance comes from AMR spin-off iFi Audio. Their S/PDIF iPurifier is a corrective appendage that promises to improve the sound quality of any S/PDIF restricted device, all for US$149. Is this the single most affordable S/PDIF re-clocker currently in production? I believe so.


This story has been on hold since May when we first caught AMR/iFi mainman Thorsten Loesch and his S/PDIF iPurifier at Tokyo’s Fujiya Avic headphone festival. Back then, Loesch’s latest fingerbob had yet to go into full production but he had a prototype on hand to show off the unit’s twin-board internals.

“With a Bill of Materials (BOM) that stands at 53 individual components, be assured that beneath its unassuming exterior, there are two separate PCBs, each mil-spec’d and packed to the brim with advanced technology”, runs the S/PDIF iPurifier’s promotional copy.

The story goes like this: Loesch first took some of the S/PDIF input tech found in his high-end multi-thousand dollar AMR DP-777 DAC/pre and applied it to the more affordable iFi Audio product range, specifically the iDSD DAC and Stereo 50 ‘Retro’ system.

Loesch later relocated those devices’ power rejuvenation and data re-clocking tech into a standalone device, the S/PDIF iPurifier, a thumb-drive sized dongle that plugs directly into the coaxial input of a DAC (a la Audiophilleo) or to a DAC’s TOSLINK input via the supplied optical fly-lead and mini-TOSLINK adaptors.

This 5-minute video interview with Loesch fills in the blanks:

I’ll confess to being somewhat unclear as to how exactly the sole coaxial input doubled as TOSLINK input until the review arrived last week: that coaxial socket’s centre hole also accepts a mini-TOSLINK plug. Clever.

Nerd note: both coaxial sockets are audiophile-approved 75 Ohm. An adapter is supplied for conversion to BNC should you need it. So too are a pair of plugs that take a TOSLINK plug to mini-TOSLINK.

The upshot? We’re covered for TOSLINK in and out, coaxial in and out, coaxial in and TOSLINK out and vice versa. Four options that point us to the iPurifier’s basic utility as a simple format converter.

One might use this iFi dongle to route the coaxial-only digital output of the Devialet Expert 200 into the TOSLINK-only Devialet Dialog which in turn deals audio out to a pair of Phantoms. Extreme – but possible.


As a S/PDIF re-clocker, the iFi device’s intent is to “restore the square wave” that journeys along coaxial or optical cables from streamer to DAC with the latter’s receiver chip must translate to ones and zeroes. By Loesch’s own admission, this iPurifier (there is also a USB version) nods in the direction of Genesis’ Digital Lens which, back in the late 1990s, sold for US$1800. This iFi pipe cleaner clocks in at one tenth of that. Progress!

In targeting jitter and electrical noise, the iPurifier: 1) reclocks the digital audio signal; 2) galvanically isolates the source device (e.g. GCA) from the DAC; 3) takes its power from a low-noise 5V iPower SMPS (supplied); 4) specifies a Femto clock for superior timing of the bitstream as it leaves the devices internal buffer.

Unlike Wyred4Sound’s more expensive Remedy which outputs 24bit/96kHz irrespective of the PCM input, the iFi dongle messes not with the bits. The absence of an internal sample rate converter (SRC) within the iPurifier sees 16bit/44.1kHz come in and 16bit/44.1kHz go out. That holds for all sample rates up to 24bit/192kHz PCM and DSD sent via DoP.

(For those looking to iFi ‘correct’ DVD players or Blu-Ray spinners, Loesch’s S/PDIF contraption will readily parse Dolby Digital and DTS but these remain beyond the remit of this publication.)


At first blush, the iPurifier almost seems over-specified for its intended target/s: mass market streamers and disc spinners. In this scenario, better to be overcooked than underdone.

For the Google Chromecast Audio (GCA), digital audio file compatibility tops out at 96kHz but the majority of end users will be using it for cloud streaming from the likes of Spotify, Tidal, Google Play, Deezer, Mixcloud, Soundcloud or any other Google Cast-enabled app.

Time to plug and play. Would the iFi S/PDIF iPurifier improve the sound of the GCA’s digital output? Does Grizzly Adams have a beard? Does a one-legged duck swim in a circle?

Often it takes days, weeks even, to ascertain the qualitative differences between digital sources and sometimes, rarely, it hits us from the first push of play. One of those sometimes is now.

With the iFi pushed directly onto the Peachtree Nova150’s coaxial input socket and fed Tidal HiFi streams by the GCA, the improvements to Nick Cave & The Bad Seeds The Boatman’s Call were immediate and obvious. The loudspeakers in use were the Spatial Audio M4 Turbo S.


We’ll exemplify with the album’s second cut “Lime Tree Arbour”. With the iFi in place, bass notes took on better shape and definition, no longer lost to woolliness or obscuring organ sounds themselves, which in turn implies better separation.

The piano motif that introduces us to the song’s second verse benefitted from a notable – i.e. not subtle – reduction in glassiness.

Layer separation went up several clicks. Put another way, midrange congestion became less of an issue. This then brings us to the most obvious improvement heard from an iFi-spruced GCA: a MUCH taller soundstage.

The S/PDIF iPurifier also improves player definition and location – a finding took more time to deduce as well as a cut over to a different source device: the 3rd generation Apple TV. With AirPlay on board the Apple slab can run as a 16bit/48kHz-restricted Roon endpoint; no biggie for Redbook rovers. As a solo player, the Apple TV’s underperformance with overall avidity was palpable. Here again, like the GCA, the iFi thingamabob brings a conspicuous improvement.


Ditto the Sonos Connect which, with iFi correction applied, moves within a hair’s breadth of the AURALiC Aries Mini as digital streamer. Of course, the Sonos brick doesn’t do hi-res audio, nor will it host a USB-connected or internal hard drive. As an aside, the Aries Mini’s onboard D/A converter remains quite a bit better than that found in the long-toothed Sonos.

Adding spice to this story is my final finding: the iFi S/PDIF iPurifier lifts even the Aries Mini’s S/PDIF game. The with/without delta isn’t as large as with GCA or ATV but it’s enough for the do-or-die optimiser to sit up and take notice.

For those who would readily drop the same coin on a S/PDIF cable – there are many of us, let’s face it – this iFi is an easy call to make, if only to make the Google Chromecast Audio more pallettable.

Thorsten Loesch’s latest device is as sharp-shooting as digital audio devices come. Readily discernible results for an easily digestible asking price. You cannot reasonably ask for more than that. DAR-KO Award, no question.


Further information: iFi Audio


Written by John H. Darko

John lives in the NOW + HERE = NOWHERE. He derives an income from the ad revenues of DAR. John is also an occasional staff writer for Stereophile, 6moons and TONEAudio.

Twitter: DarkoAudio
Instagram: DarkoAudio
Facebook: DAR


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    • I didn’t conduct that comparison as the predominant context for the piece was the GCA and to a lesser extent the Apple TV. That I found time to put the iFi onto a Connect and comment on its performance should be seen as a bonus.

  1. Might seem a silly question, but where do you buy the iFi SPDIF iPurifier (I can’t seem to find any online sales here in Oz).

      • I looked before on the Maxmedia website, but couldn’t find it. Now had another look and after going down lots of rabbit holes eventually found it. Not the best website to find what your looking for.

        Ok, not too bad a price, but is a big jump if looking at at cheap Chromecast to plug into 2nd/3rd hifi option (if not liking for great quality then Chromecast would be ok itself).

  2. You review reclockers better than anyone out there 😉 bought my Remedy off your recco (used between a Sonos Connect and a Devialet 120) but not a fan of the SRC, I feel like the sound is a lot more relaxing with improved presence and soundstage, but comes at the cost of PRAT… wondering if it has something to do with the odd ratio of red book to 96k (x2.17 etc, 44.1 –> 96)… really like the fact the ifi doesnt perform SRC and would love to see them compared.

    Any word from the vendor on a date when he expects them to be available at retail?

  3. Now it might be useful to compare the GCA + S/PDIF iPurifier to the nano iDSD, since they are in a similar price bracket. Yes it is S/PDIF vs USB, and yes the GCA may be a more likely gateway drug to hi-res music… which then needs an S/PDIF fix. But if trying to get someone into the hi-res game at a low entry point, you might want to compare to the sound of the nano iDSD which has its own DAC (not the micro, which is a good bit more expensive). Might be instructive.

  4. The perception that DAC’s, streamers, or purifiers are digitally transparent, acting as “digital wires” from the streaming source to the digital output needs to be addressed. This transparency is not always the case, and when it’s not the case, it can be challenging to identify and isolate.

    I believe that most people think there is a transparency and when a variance is detected sonically then that variance is the result of something external, like jitter and digital waveform degradation, that has been corrected. These way very well be factors, but digital streaming and transmission is a complex process with many stages including undocumented algorithmic (digital signal) processing. What evidence is there that the iPurifier is equivalent to a digital transmission wire?

    Jitter is something inherent to S/PDIF and should be properly accommodated for on the receiving side, unfortunately that is not always handled consistently – this needs to be the discussion basis for using devices for which this post is centered.

    Noisy and significantly malformed analog waveform representation of the digital pulses is a flaw of the transmitter design. I want to make this point, as in such a case, it’s much better to do the correction as close to the transmitter as possible.

    I close with this question: If the transmitting device and the cables are so bad, is there a case for an iPurifier on each end of a S/PDIF cable? And does that configuration make a difference?

  5. I’d think this device is actually more useful than you let on John. My iBasso DAP has an S/PDIF output that I feed to my iFi iDSD. Would love to try this device now in my portable rig.

  6. Thanks for the heads up, I will definitely get one, as agree the digital out isn’t great on gca. I do think you should give the analog out another try though as it sounds great when used with phone powerbank with ‘full dynamic range’ switched on in settings.

  7. Okay, Darko; I’d love to hear more about how noticeable the improvement was with the Apple TV? (That’s my streamer)
    Is it that the Googlecast is such a music dung heap (although smashing for the price), and I should expect less gains on the Apple? I am running it all on a Darko-approved Redgum/LS -50 rig.
    Availability, even in iFi’s home state in the US, has been challenging so far.
    They only sell through their dealer network- no direct sales.
    (Your love of word about music resonates with me- keep up the good work)

    • You should expect gains from the ATV with iFi applied but not quite as drastic as the GCA because the latter’s starting standard is lower.

  8. I’m intrigued. So, in USD, did the iFi plus GCA deliver at least $185 worth of value to you, or do you prefer other solutions in the bargain basement? My main rig resolves CDs quite well, and I do have a GCA hooked up to it for casual listening, like when I’m streaming Spotify and listening from another room. I wonder if the iFi might entice me to sit down in the same room. I don’t quite have the spare change for the Aries, yet.

    • I can’t really speak to absolute cash values, only relative ones. This thing renders the GCA listenable and I’d call that a win IF you can tolerate an absence of gapless on behalf of Google. Where it really shines for me, being a big Roon fan, is with the Apple TV.

  9. Does this device make any difference if the stream you are dealing with is compressed? Will it make any improvement to a medium to high quality mp3 internet radio streams such as Radio Paradise, Pandora, or premium quality Spotify?

  10. John, fun review. I use an oppo bdp 103 for disc spinning and streaming from my network. I have the oppo connected to the onboard dac of my peachtree 125se via toslink. Do you think the ifi purifier would improve upon things? Thanks.

    P.S. is it safe to assume you are reviewing the Nova 150? If so, can’t wait.

  11. Dear John,

    I would be interested in your opinion on the airport express + ipurifier + bifrost combo compared to the same combo but without the iFi dongle. From the picture of your review it looks it is connected to a bifrost dac, but there is no mention of it in the text.


    • The Schiit DAC was only used for a single afternoon but its results with the iFi dongle reflected those heard with the Peachtree.

  12. Great review. I wonder how effective this would be on the toslink I run from my tv to my DAC for movies, games, etc? Presumably the benefits are more noticeable with music, but I assume my tv’s digital out could benefit as well.

  13. After about a week on searching, I managed to snag the only one I could find in the U.S. (On the other coast, of course) The shop owner was disappointed as he wanted to try it himself. He only had only received one from IfI. Another week of anticipation until I can hear it myself….

    Darko, your words cause me to open my wallet. Please stop. 😉

  14. I use an iFi USB Purifier 2 in conjunction with an iFi USB Power, between my SBTouch and MDAC, for me there’s a significant improvement…

    I’d suggest any benefits gained from these types of devices will be DAC dependent…

    FYI I’m in the UK so can’t help with a distributor.

  15. Nice review. I get the benefits of something like this on budget items like GCA where the interference and jitter are likely degrading the output signal quality.

    But would you expect the iPurifier to provide a noticeable improvement with streamers further up in price such as the Bluesound Node2’s digital output, or Moon 180 Mind?

  16. John,
    I have just checked with the AUS distributor and they officially have the SPDIF Ipurifier in stock. Better still they have confirmed that they can (will) supply with the IFI PSU.

  17. Just received my iPurifier. There was so much increased demand due to this article, it took a week to get stock. Added it to my Bluesound Node 2 and oh my days, this is the real deal. I’m not as good at describing what my ears hear as John but the timing seems better and the music (especially dynamic stuff) seems less ‘bunched up’ which I didn’t think it even was with the Bluesound, until I added this. I’m using coaxial because my amp doesn’t support 24/192 on toslink but it does with coax.

    I wonder if the Wyred 4 Sound version is even better, for the high price? If it is better, might be worth going straight to the Wyred but I’m happy with the iFi FOR SURE.

  18. I use it between my HiFiBerry Digi+ and the dac and i love it. I wonder however, since it comes between the SPDIF cable and the dac, if the quality of the cable makes any difference or if it is irrelevant at this point.

  19. It took a while to arrive but it was worth the wait.
    An immediate and obvious overall improvement from Tidal on iMac via Peachtree iNova as a DAC/Pre, all through Toslink.
    Not many people realise (including the “genius” I spoke to at Apple) that the iMac headphone socket also accepts a mini Toslink plug ($5 @ Jaycar) to allow optical-out.
    So, while I’ll keep it all optical for now, the supplied fittings with the iPurifier enabling different ins and outs is really handy and something I’ll likely muck around with one rainy day.
    Bang for buck? 10/10!

  20. Just plugged one into my Schiit Modi Multibit DAC via Bluesound Node 2 via coax running Tidal. Yes, it sounds better.
    I haven’t tried To slink yet, but I’m wondering if that’s even better? Anyone?
    Also, what happens if you connect the ifi to the streamer, then link to DAC via coax, instead of ifi into DAC?

  21. To Andreas,
    Actually you do not need to use a reclocker for HiFiBerry Digi+, it uses a perfect jitter removing chip Wolfson WM8404, the only problem on it is the noname 27 MHz quartz oscillator. The creators of HiFiBerry Digi+ had to offer few buck more expensive “audiophile” version of it with upgrade to proper ultra low jitter oscillator such as for example Crystek CCHD-575, and that’s it – they would save a lot of money to their customers and increase sales of HiFiBerry Digi+ enormously.

  22. Tried my ifi purifier and it does improve SQ without a doubt, unlike the AQ Jitterbug which didn’t do much on my system. For the Ifi P I had Roon core on a Mac Mini out to a Gefen Audio extender via Ethernet to my listening room, out the Gefen receiver, into ifi P and then to my DAC. My other system is a Moon Mind HD 180 which was still better than the Roon set up, but not by much!

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