iFi audio ZEN Stream

Intro:

IFi kindly lent me a Zen Stream for review purposes. This write-up reflects my honest opinion based on roughly two months that I spent with the Zen Stream. My experience with streaming is relatively limited, as I mostly use my extensive FLAC library which I built up in 12+ years from several sources. I never really felt the urge to go full-on streaming, I prefer to enjoy and fully embrace a new album that I discover as opposed to the superficial mass consumption which often comes with streaming. At the same time I have always seen and recognised the benefits of streaming, like the ease of access to new music. Many years ago when streaming was new, I always found the sound quality to be inferior compared to my FLAC collection. The world has changed since then.



Do you need a streamer?

Since you are reading this, you most likely already know what a streamer is, but you might not be sure whether you need one. Streaming is possible straight from your computer to your DAC, but a dedicated streamer will completely separate your music server connection from your computer, eliminating all kinds of electronic noise from your audio chain which you might not even realised was there. I find it important to note that the level of noise can vastly differ from computer to computer. DAC inputs, galvanic isolation, quality cables, power supplies, conditioners further filter noise so the same streamer may improve sound to different extent on different computers. In my opinion you need to have a relatively good DAC/amp to consider buying a streamer for sound quality improvements. If you only use a USB dongle, you are probably fine with streaming from the computer.
I think it is worth mentioning, that the noise we are talking about is not a buzzing electronic noise that one might first have in mind, this noise is a lot more subtle and you might not even realise it is present in your audio system. It can manifest in a slightly harsher, more metallic treble for example.



Zen series:

In my opinion iFi's Zen series (DACs and amps) is one of the best value for money when it comes to entry level audio. The Zen Stream is part of this product range, sharing the same strong and well built aluminium chassis. The Stream however stands out from the Zen series, as with the correct settings its audio quality (or shall we say noise eliminating abilities?) can compete with streamers for three times the price. A new Zen Stream these days can be found between £319 and £399 depending on the retailer. I know audio enthusiasts who sold their £1200 streamers for the Zen Stream as they found the sonic qualities to be equal or better. I personally can only attest to the ZS (Zen Stream) sounding better than the Blue Node 2I (£549) but I trust my friends' ears, and their findings are also supported by several online reviewers.

This exceptional price/performance ratio however does not come without compromises. The ZS is such a minimalist device, it does not even have a screen or play/pause button like most streamers do. The user experience is not the friendliest and it is certainly not for everyone. The ZS is also not without glitches and connection issues, but luckily iFi is constantly working on it, improving things with every firmware update. More about this in the software/app section.

Modes:

Despite being a minimalist device when it comes to external and internal design, the ZS is quite multifunctional (as many iFi devices are). Beside the 'All in one' mode you can choose a dedicated mode for Roon, Tidal, NAA (Network Audio Adapter) and DLNA. The dedicated modes cut off all the unused physical circuitries inside the ZS further decreasing digital noise, which leads to an even cleaner sound than in AIO mode. Here I will only cover 'All in one mode' and 'Tidal exclusive/Tidal connect' mode.



My Tidal experience:

It is not my first time using Tidal, but I had to renew my subscription in order to use the ZS. My ideal choice would probably be Qobuz, but there is no dedicated mode for Qobuz on the ZS, and also Tidal is available in a lot more countries. The country where I travel the most, is currently not covered by Qobuz, so the choice for me is easy.
I tried Tidal Master, but found only about 20% of my music available in 'Master quality' and I am not a big believer of MQA anyway. The recording matters a lot more than regular Tidal Hi-Fi versus their 'Master quality'. I found the difference negligible, certainly not worth twice the subscription price.
I also found that while Tidal offers 100 million songs, around 10-15% of my music is still missing from the streaming provider, so my FLAC library is not going anywhere. Apart from this I find Tidal relatively easy to navigate and I love the immediate access to this music universe. One function I really miss though is to shuffle play through my entire collection.

IFi software and app:

As you probably figured, if you are a Tidal user it is best to stick with the Tidal app. iFi does have a user interface which is available from your web browser, but you can only access it in 'All in one' mode. The user interface itself is simple, but handy. You can update the firmware from here and also see what is on your connected SSD. I connected a 512GB SSD to the ZS, but the number of albums the ZS was able to scan varied from listening session to listening session. Navigation is also quite sluggish, switching albums, skipping tracks can take 1-3 seconds. So to me it never worked flawlessly, but it is good to have this function nonetheless.

I tried iFi's android app too, which is also under constant development. At first the app worked and I was even able to refresh to the newest firmware using it, but after that the app collapsed and stopped working. Even after reinstalling it I could not make it work again, as it simply cannot see my Wi-Fi network anymore. The app's current rating in Google Play Store is one out of five stars from 126 users.



Sound quality:

As I mentioned earlier, in the traditional sense we cannot really talk about sound quality in case of a streamer. Headphones and amplifiers bring something to the table which you can evaluate, a good streamer takes away all the unnecessary things from the same table. Its utmost function is to clear, clarify, purify the sound, separate music listening and isolate the sonic experience. The result will vary from system to system, but if you think your system is noise free, you might be up for a surprise. When it comes to sound only, the little ZS rivals streamers that cost not just two but three times more.

My personal experience:

I never really found my laptop noisy and I use relatively good cables (Supra Excalibur, good power cables). Yet the difference between FLAC straight from my computer and Tidal even in AIO mode was immediately obvious. I would not say it was a night and day difference, but clearly audible. At first I was not even 100% sure which one I prefer. FLAC from the computer somehow sounded a little punchier and brighter, but also flatter and less refined, especially in the treble. FLAC files in Foobar/ASIO from the computer sounded a little less natural, edgier, treble a bit more metallic/plasticky, texture, body and depth slightly lacking.
From the ZS a blacker background was immediately noticeable. The sound felt warmer, more organic, more natural and rounded. Depth and space due to the blacker background has increased, with this darker background details were easier to pick up. I must emphasise, these differences were not enormous, but with a little attention all of them became noticeable.
The slight harshness I hear from FLAC/computer versus ZS is due to the subtle electronic noise. The main reason I hear the ZS warmer and smoother is because my DAC and amp are warm and smooth. (Pegasus R2R and Cayin HA-3A). So the ZS is doing its job letting the DAC/amp sound at their best, as they should.

When I switch to Tidal exclusive mode, I unfortunately lose the (buggy but still useful) access to my SSD connected straight to the ZS. I also lose iFi's browser interface, but what I gain is an even higher level of clarity compared to AIO mode. The improvement between AIO mode and Tidal exclusive mode is less than it is between FLAC/ASIO computer and ZS AIO streaming, but certainly present and audible. In fact if I bought a ZS I would probably use it in exclusive mode, as with the clarity improvement maxed out it can really elevate the listening experience and become a worthy sonic upgrade.

As long as someone does not mind its quirks, this little streamer will satisfy most users when it comes to pure sound.



Issues:

To see the full picture I have to list the issues I have encountered with the ZS. I mostly used Wi-Fi because my router is 15m away from my audio gear and I have good, stable Wi-Fi. The ZS was always immediately showing 'strong connection' with its led indicator. There should not be a sonic difference between Wi-Fi and wired ethernet connection, but I can imagine some of the connection issues I have experienced could be eliminated with wired ethernet.

- First of all when I switch the ZS on, there is an audible noise (a bit like a plane before take off) until the streamer connects to the Tidal server. This noise never occurs later on, even if the server connection gets lost, only after switching the ZS on. I was told, this is not a common problem and most likely it has something to do with my DAC. I use a Musician Pegasus, and another member has experienced similar noise with his Denafrips DAC. The DAC designer is the same, so it might have something to do with the DAC design and is not the ZS's fault. Ifi will look into it and might come up with a remedy in a future firmware.
- Sometimes I just can't stop the music from playing. This usually happens after hours of listening, but even closing the Tidal app does not help. In this case only switching the ZS off can stop the music.
- While the ZS always connects to the Wi-Fi network in a few seconds, sometimes it takes a few minutes and attempts to connect to the Tidal server. During these 2-8 minutes I sometimes have to restart the ZS 2-3 times in order to succeed. There is no pattern I can observe, it is completely random and temperamental. Once the connection is set, it is very stable as long as I keep listening. I never had a drop out while playing music.
- If I stop the music and after 15-20 minutes I click 'play' again, the server connection is not always immediate either. Sometimes it takes 2-3 attempts to play music again and occasionally I have to restart the ZS.

Restarting the ZS usually solves any problems, but the first few minutes trying to connect to the music server can be frustrating, at least on Wi-Fi. Wired ethernet would probably solve most of these connection hiccups, but I have not yet been motivated enough to buy and install 15 meters of ethernet cable. Also, Wi-Fi in theory should work just as well.



Conclusion:

Value and compromises, who is the ZS for?

I only covered one usage scenario in this review, Tidal through Wi-Fi (and SSD). Roon users for example might not encounter any of the problems I have mentioned. The ZS is a minimalist, yet versatile device and as long as you do not mind to figure out its quirks, the sound quality for the price will repay your efforts and dedication. If you are not in the position or you simply feel uncomfortable spending more than £1000 on a stand alone streamer, the ZS can bring you the same level of sound quality but it comes with certain compromises regarding the user experience. What compromises you are willing to make and to what extent, only you can answer. Despite all the annoyances I have experienced I am seriously considering buying a ZS as it truly enhanced my listening experience.

Edit:

I have made two discoveries which helped with most of the connection issues with the Tidal server.

1, I know, it sounds odd, but loosing connection is tied together with the 'lock screen time' on the computer. If I change my screens lock time/sleep time from 10 minutes to 30 minutes, the connection stays alive. This helps if I leave the computer/stop music for a few mins as when I come back I do not have to go through the frustrating connection process again.
2, I need to leave the Zen Stream on 24/7. Like with many DACs, it does not hurt the ZS to be on nonstop. This way I can avoid the noise and initial frustration to connect to the server after each switch on.

Perhaps the solutions are not ideal, but they work. I could probably live with the ZS this way, yet I think I will look for another streamer.

ACKNOWLEDGEMENT
Many thanks to Lawrance over at iFi - who has been patient and supportive of getting me info and started with product the past few years. This is my purely subjective review – based on my gear, my ears, and my experience. Please consider and respect this - especially if my impressions do not match your own.

I have used the iFi Zen Stream, (Going forward I will refer to it simply as " Zen Stream") extensively over the past 4 months, and I have clocked a lot of hours with the streamer. This review is MUCH later than I had anticipated because I realized that my then-current audio setup wasn't resolving enough to fairly comment on the capabilities of the Zen Stream. I had to wait for new headphones & amp to arrive, then break-in, and get to where I felt I had a decent baseline again to resume evaluating performance.

You can read specs anywhere, so for the sake of brevity, and since this is coming out much later than anticipated, I will stick to how my experience went and how the Zen Stream fit into my stable of audio devices.

Setup
For this review, I used the Zen Stream PRIMARILY from Tidal & Amazon MusicHD. I also tested against Local Network audio files stored on my PCs and NAS (Network Attached Storage) drives to see differences (if any) in performance. I am not a ROON user, so sorry, I couldn't get myself comfortable enough to try and comment on that functionality.

To ensure that I wasn't penalizing the Zen Stream for sonic differences/preferences, I tried it with a good selection of amps. (Hint: The thing is dang NEUTRAL. None of the amps "liked" or "hated" the Zen Stream.)

In the end, the way I spent most of my time listening to it via Apple, Android, phone, or tablet was like this:
Setup: iFi Power Station-iFi Zen Stream-Denafrips Pontus II-Burson Soloist 3x-Harmon Kardon HK-870-HiFiMan He6se v2 - Running off HK-870's 100w per channel speaker taps. (Yes, to ensure that there was NO question that I was getting the most out of the He6se v2, I A/B'd the Burson 8wpc EXCELLENT headphone amp's Balanced XLR-out against the HK with a speaker tap to XLR adapter cable, and the HK clearly won for dynamics and soundstage, volume-matched with a BAFX3370 decibel meter.)

With the unit sitting right under the spare TV connected to Denafrips Pontus II DAC, Burson Soloist 3x doubling as headphone amp and pre-amp for my Harmon Kardon HK-870 power unit with XLR headphones driven off the speaker taps. (I wanted to see how long it would take for my wife to comment...) In order to better realize the capabilities, I had to upgrade my amplification to properly drive my new HiFiman he6se v2 headphones that I had gotten so that I had something to contrast my HEDDPhone One which was the highest resolving headphone I had. (While my other headphones sounded great, none of them had the resolving capability to truly discern the differences between streaming sources. I imagine this is tied to the argument where people say, "All DACs sound the same." because from my favorite daily-driver headphones: HD-650s, ATH-AD900Xs, Beyerdynamic T1 v2, and others, listening through my Topping A90, Asgard 2, and other entry-level amps there really wasn't a clear difference. They just didn't resolve highly enough to show the differences in levels of performance.)

All this upgrading should give you the idea that the iFi Zen Stream is a VERY technically/sonically capable streamer...
I had to swallow a bitter pill of humility and admit that the amps and headphones I had on-hand weren't up to the task of adequately reviewing Zen Stream.

Right - Now with all that out of the way, on to what matters!

WHAT IT IS
The Stream is a solid-state dual-band Wi-Fi streamer supporting 802.11a/b/g/n/ac from iFi’s ZEN line of products which also includes an ANC noise-reduced USB or iPurifier SPDiF digital connection out to your DAC or multimedia hub.

For my setup the BEST sound came from this chain: NAS-->iFi Stream-->PontusII DAC-->Burson Soloist 3x (Pre-Amp)
-->HK-870-->HiFiMan He6se v2. (Major boosts in dynamic range, spacial placement within soundstage, and greater resolution.) HEDDPhone One came close and was much easier to achieve it's best as it sounded great just from the Burson Soloist 3x Performance amp. Oddly enough, while listening through the HK-870 gave way more power, it actually took a little away from HEDDPhone's clarity & separation.

2nd place: TIDAL-->iFi Stream-->PontusII DAC-->Burson Soloist 3x (Pre-Amp)
-->HK-870-->HiFiMan He6se v2. (Slight drop in dynamic range, and resolution.)

Close 3rd: Amazon HD-->iFi Stream-->PontusII DAC-->Burson Soloist 3x (Pre-Amp)
-->HK-870-->HiFiMan He6se v2. (Slight drop in spacial placements within soundstage, resolution varied more by track.)

*Large gap between 3rd & lower* Differences between Tidal & AmazonHD now negligible.

4th: TIDAL/AmazonHD-->iPad/iPhone/Android Apps-->PontusII DAC-->Burson Soloist 3x (Pre-Amp)
-->HK-870-->HiFiMan He6se v2. (No major difference between the Android's "direct" and IOS "Airplay" implementations for access of the Zen Stream on audio performance.) (Noticeable drops in dynamic range and resolution. A much "smaller" sound and a less engaging listen.)

5th: TIDAL/AmazonHD-->Sony Smart TV App-->PontusII DAC-->Burson Soloist 3x (Pre-Amp)
-->HK-870-->HiFiMan He6se v2. (Major drops in dynamic range, spacial placement within soundstage, and resolution. Sounded comparatively small and "flat".)

REFERENCE MUSIC BY GENRE
Rock –
1. “Kryptonite” – 3 Doors Down (The lead jumps out from the power chords beneath, & lyrics are SUPER (Haha!) clear.)

2. “Du Hast” – Rammstein (What? This WASN'T just cool because it's loud? There's subtlety in there?!?!?)

3. “Why Me?” – Planet P (Opening effects, SOLID and controlled bass-bounce, panning)

4. “Hotel California” – The Eagles (Detail of the strums, instrument placement, the vocals are completely on-point!)

5. “Money For Nothing” – Dire Straits (Panning, instrument placement, background effects, & that awesome "3d effect"!)

6. “Amaranth” – Night Wish (The SIZE of the stage is huge, & when resolved properly, isn't just a "wall of sound" coming at you.)

7. “Money” – Pink Floyd (Opening effects, controlled bass, panning, background effects.)

8. “Lucy” – Skillet (Lead vocals are on-point, and isolated in a black background.)

9. “Layla” – Eric Clapton (Clean vocals, guitar, and percussion instead of a "wall of noise" you need to pick through.)

10. “While My Guitar Gently Weeps” – Jeff Healey (That SOLO!!! Jeff's voice just grabs you out of the black.)

Blues/Jazz –
1. “Round Midnight” – Thelonious Monk (Each bass pluck, the breaths of the sax player, and the piano has "bite" when clean keystrikes, and rolls when his attack is slightly "off". A REAL piano sound.)

2. “Smoking Gun” – Robert Cray (Smooth, and the bounce is tight, I can truly hear more than just the bass, stellar guitar, and main riff behind Robert's vocals.)

3. “A Night In Tunisia” – Dizzy Gillespi (I can clearly hear the piano, (Even the missed notes!) people in the audience, breaths of the sax player, and of course Dizzy sounds remarkable.)

4. “Mood Indigo” – Duke Ellington (The strings scratching on the bass, the breathing of the clarinetist (Is that a word?), the piano (Again, missed notes I never noticed before!), the subtlety of the flutters from the sax, and even the clacks of the sax keys. And those trumpet "wawas" never sounded so gravelly & epic before.)


CONCLUSION

For $399 (At time of this review) the iFi Zen Stream offers serious audio performance above what I'd consider "commercial" audio product capability. As a source, the Zen Stream didn't change the "sound" (warmer/brighter) vs other sources. It DID however seem to determine how much information (detail and sound space structure) reached my DAC for it to work with. Can you enjoy streaming music directly from a PC, Android/IOS tablet, or phone? Of course! And if you want to passively listen to your tunes, then that's all you need. But if you want a source that will likely exceed the capabilities of the average consumer's gear, (With the trade-off of a slightly more technical setup process than some higher-cost solutions.) and that will allow you to "grow" a system around it as you slowly upgrade the rest of your audio components, then the Zen Stream is a solid piece of kit to have in your arsenal.

The iFi ZEN Stream was kindly loaned to me for the purpose of this review and as always I am providing my honest and subjective evaluation.
All links provided are not affiliated and I don't earn anything by clicking on them.

Introduction

The ZEN Stream is the latest addition to the popular iFi ZEN range that consists of various well acclaimed, value for money, desktop audio devices.
The ZEN Stream is a mid-priced network streamer that integrates all the available methods of streaming over Ethernet or WiFi without relying on the noisy PC.
The price is €399 and is available from all iFi authorized dealers.

Technical information

Beneath its classy exterior, the ZEN Stream is a technological streamer-de-force.
It has one purpose – to send music simply from the Internet to your DAC with no loss of quality.
True hi-res performance of PCM384/DSD256 via WiFi/LAN.
Just add your smart device as a remote and away you go.
Optimised open-source architecture – works with multiple dedicated platforms, completely and perfectly future-proofed as it is constantly updated.



ZEN Stream is a true ground-up design by iFi — the hardware and software implementation is quite exceptional
Two SuperSpeed USB3.0 ports with Active Noise Cancellation II
S/PDIF out with the iPurifier built-in.
iFi software developed with Volumio open-source as the starting point, then coded and optimised by us to achieve the purest streaming software bar none.
These are some of the factors behind why the ZEN Stream is at the cutting-edge handling PCM384/DSD256 on LAN and WiFi (802.11n, with 100Mbps on 5Ghz).

From the device’s drivers, to the kernel (the heart of the operating system), to the shell (which interfaces with the kernel), to the applications and the user interface — everything is fully optimised for seamless operation and excellent sonic performance.

An ingenious part of the ZEN Stream’s design is the ability to select between ‘Exclusive’ modes – individual settings dedicated to specific modes of operation to deliver the purest possible performance.
All other programs are shut down – to minimise ‘software jitter’ — an often overlooked aspect that negatively impacts the quality of computer audio playback.

This ensures that the ZEN Stream is not merely a ‘jack of all trades’, but a master of all too.

All-in-one (AIO) covers all modes
Roon only (not available at the time of the review)
Tidal streaming
NAA streaming
DLNA streaming



So with ZEN Stream we can

Stream straight from Spotify/Tidal apps with Spotify Connect and Tidal Connect.

Works with any DLNA certified streaming app including the recently released iFi own app.

Integrated Airplay and Chromecast (not yet available) easy streaming from Apple and Android devices.

ROON Ready functionality to be added in a future update.

NAA operation in conjunction with Sygnalist’s HQPlayer software.

Hardware

Beneath the unassuming casework sits some serious horsepower in terms of both technologies and components:

Powerful 64-bit quad-core ARM Cortex microprocessor.
USB and S/PDIF interfaces regulated by femto-precision GMT clock to eradicate jitter.
Active Noise Cancellation II and iPurifier technologies for USB and S/PDIF interfaces respectively.
Intelligent Ethernet switch controller.
High-PSRR, low idle current, low-dropout voltage regulators with soft start.
Synchronous 1.6MHz high-speed precision power supply controller.
C0G capacitors and Taiyo Yuden and Murata low ESR inductors.



Build quality and appearance

The ZEN Stream shares the same physical appearance with the whole ZEN series so they can be stacked together.
The case is made from a combination of metal alloy and aluminium with a nice finish and good build quality.
At the front there are two small press buttons that both feel a little loose and two multicolor LEDs that inform the user about the connection status and the streaming bitrate.
The back is heavily populated with the DC jack, a LAN port, a USB type C port for system only service, two type A female USB ports, (one for connecting a hard drive/USB stick and the other as a USB audio interface), the Coaxial output, the exclusive modes switch and the WiFi antenna.
The unit comes bundled with an iFi iPower 9V or 15V DC supply (both work), a short Ethernet cable of good quality, the WiFi antenna and a plastic screwdriver for the modes switch.
The first batch of the product includes as a bonus the upgraded iFi iPower instead of the generic power supply.



Setting up and operation

Initial setup is quite easy and almost plug and play as long as you follow the included quick start manual.
"Almost" because for some strange reason we didn't manage to configure it through the Ethernet connection but instead we used the WiFi hotspot method that worked like a charm.
Anyway it is pretty easy to get started and then the Stream will seamlessly work either wired or wirelessly without any further actions from the user, just press ON and after a few seconds you can start streaming.

The unit gets quite hot during operation and the exclusive mode switch needs a screwdriver in order to turn something that is not very practical especially if you use various streaming methods and you need to change the settings frequently.

Web based UI

In order to access the menu you have to open a browser and type the IP address "192.168.211.1" and then a web based UI will pop up displaying all menus and the music player home screen.
The graphical environment looks quite similar with the original Volumio but with a practical customization done by the iFi software developers.
Sometimes if you unplug the streamer and power it again the above IP address will change and you have to use an app like Fing to find it.
Learning curve is quite short and you don't have to be an expert in order to operate the Stream as it is very simple and a few minutes of exploration and experimentation are enough to successfully master it.



iFi application

While writing this review, iFi released their own Android and iOS compatible application to control the ZEN Stream.
All control and playback actions can be performed through the application which shares the same graphic environment with the web browser interface but this time you don't have to deal with IP or anything else.
Just launch the application, wait a few seconds for the Stream to be recognized and you are good to go with all menus and actions available at the palm of your hand.



System updates

iFi is very actively supporting the Zen Stream by releasing frequent updates that improve the performance and solve various bugs.
Updating is not automated and the user must manually check whether an update is available or not.
If an update is available you have to press "OK'' in order to download it and then it gets installed without the need of any further actions.
We have installed about 5-7 updates without encountering any issues with system crashing or freezing and everything worked as intended.



Streaming

We have tested the unit by streaming music from the Qobuz music service and a hard drive directly attached to the ZEN Stream USB port but we don't use Spotify or Tidal accounts.

Streaming music from an attached hard drive is easy to do through the iFi application or any other compatible DLNA/UPnP app that can access the music library.
Building the music library doesn't take too long and navigation is pretty lag - free although you might experience a certain slow down while browsing larger libraries.
Search can be performed either through the traditional file system (which is faster) or using the various tagged musical categories.
All file types and sample rates are supported, gapless playback is available and the cover art is displayed in the application player screen.
Streaming music from a network attached hard drive is easy and straightforward without requiring any complicated actions.



Regarding Qobuz or any other streaming service (except the Tidal and Spotify) there is no other way to stream except using a third party UPnP application like the BubbleUPnP.
Chromecast would be a savior but by the time of writing this review it is not yet implemented so the user must rely on the paid edition of BubbleUPnP or something similar.
Now, it is not that expensive ($4.69), it is very easy to set it up and start streaming your favorite tunes.
You just have to enter the Qobuz subscription account details and then you get access to a full Qobuz browser including managing your favorites and playlists plus a full featured search.
User interface is simple and beautiful and the only thing you have to do is to choose the iFi player from the drop down menu which lists all the available UPnP servers that are running at your home.



Of course Tidal and Spotify have their own embedded "connect" feature so browsing is as simple as it gets and it is performed through the host application itself.

WiFi signal strength is strong and we didn't experience disconnections or any kind of lag even while streaming 192kHz/24bit material and then it is up to the user to decide whether LAN or WiFi yields better sound quality.

The (not so user friendly) exclusive mode

iFi streamer features an exclusive mode system, selectable through a screw switch at the back, that kills all unnecessary tasks giving priority to the selected one resulting in a better performance.
The default switch position is the "all in one" (AIO) that is the mode to use in order to perform initial system setup, updates, all other non music related actions and of course streaming with all the supported methods.
Selecting one of the other available modes like the exclusive DLNA that we have used while streaming Qobuz, there is an increase in performance speed, for example loading playlists and skipping tracks is done faster without any kind of lagging.
The exclusive modes system seems to be useful and yield better computing performance but the implementation is not so practical.
The procedure is that you have to power ON the device with the switch set to AIO and then select the desired mode because if you power ON with the switch left to another position except the AIO, the system will not boot up.
So if you want to avoid switching back and forth, you must leave the device constantly powered ON with the switch set to the desired mode.
Of course if you need to perform any other non exclusive action, like for example check for updates then you have to set the switch back to AIO.
Furthermore if you wish to switch between various modes, for example alternating between DLNA and Tidal exclusive then you have to power OFF, set the switch to AIO and then select the Tidal exclusive after powering ON.
At the end the whole system was proven to be troublesome and non practical so after a while we got bored and left the switch set permanently to the AIO position.

*Some combinations might work without powering off or might work without any problem after powering on but the DLNA exclusive mode definitely doesn't work as it is supposed to do.



Streaming quality

The user can choose between the USB or the Coaxial outputs but one at a time because they cannot be active together.
The USB output is active and can successfully power any USB powered DAC so it can be paired with all kinds of USB DACs and not only the ones with internal power supplies.
The outgoing digital signal is jitter and noise free, totally silent without the slightest audible distortion.
All DACs we have tested, delivered a crystal clean sound with excellent transparency, great detail retrieval and without any tonal shifts.
Both USB and Coaxial outputs perform with the same quality so it depends on your DAC implementation of which one to choose.
Furthermore the iFi ZEN Stream does an absolutely excellent job in killing the noise that is generated by the dirty power supply and the mechanical parts of the attached hard drives which otherwise greatly affects sound quality.
Excellent performance that can be further enhanced by updating the power supply to the iFi Power X or even better the iFi Power Elite.
Compared to the resident reference streamer, the Allo DigiOne Signature with the Shanti linear power supply, the iFi ZEN Stream sounded a touch less detailed and not as crystalline but differences where very minimal and on the plus side, the ZEN Stream appeared to generate a slightly more organic sound.



At the end

The iFi ZEN Stream is branded, plug and play, easy to use, has a nice UI with a dedicated app, both USB and Coaxial outputs, USB input, it is wired and wireless, it has noise suppression circuits, it is competitively priced and there is continuous support through regular updates.
Two things are missing, the Chromecast and Roon support that when they get implemented as advertised then they should raise the performance bar even higher.
Till then the ZEN Stream is still the most inclusive and user-friendly network streamer in the market with a price to performance value that is absolutely very hard to beat and as such it gets our highest recommendation.

*Roon is not officially supported but Roon users report that iFi ZEN Stream is perfectly working with Roon Bridge or something like that.

Gear used during this review

Denafrips Venus II (resident DAC)
Denafrips Ares II (kindly provided on a long term loan by the official distributor www.denafrips.eu)
Topping X Shenzhen
SMSL DO200
iFi ZEN DAC
FiiO E10K TC
Everything was plugged into an iFi Power station.

Test playlist

Copyright - Laskis Petros 2021