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Music server


ZENith MkII Std

Manufacturer: INNUOS
Prices (when reviewed): &£ 2290

tel.: +44(0) 1793 384048


Provided for test by: INNUOS

do not remember when, if ever, I tested audio product from Portugal. This does not, of course, mean that there is something wrong with the audio industry in this beautiful country, but rather with me, and other audio magazines as such, focused on products made in a few Anglo-Saxon countries, Japan and Scandinavia. And this time we actually test the product originated in the United Kingdom, but with some Portuguese roots. So, one might say, is a bit Portuguese too...

Innuos is relatively young brand, as it was established in 2014 basing on the initiative of Mr. Nuno Vitorino, who, in 2009, started the LIV Connected Technology company. Three years later, he changed its name to Simply Connected, and in 2015 to Innuos. Its portfolio is divided into two main parts:
• servers, that include Music Servers and Movie and Music Servers,
• players, that include Music Players.

This distinction is, in fact, arbitrary (Jason Kennedy in his test of ZENith Mk II for "Hi-Fi +" magazine uses yet another name: "renderer"). The Players differ from servers with only one element: they do not include storage space for music. I must say that for me it is a completely incomprehensible distinction because from the user's perspective it does not matter to me whether I use a NAS, USB stick, USB disc connected to the USB port or an internal disc. A streamer and a player, for me, are exactly the same "files transports" (similar to a "CD transport"). But the distinction quoted at the beginning is commonly used so I shall stick with it.

The server under review, ZENith Mk II Std, is a top model in this manufacturer's portfolio. It is an audio files player, featuring CD ripping function and internal storage – it uses 1TB solid state memory (SSD). There are also XL and XXL versions of this device with a memory capacity of - respectively - 2 and 4 TB. The device looks like a classic Compact Disc player, but without any control buttons. To operate the device one uses a chosen application installed on a smartphone, tablet or a computer.

It uses Asset UpnP software and runs Logitech Media Server. The user interface called innuOS was developed in-house. This server is build around Quad-Core Intel server CPU and motherboard. It features 8 GB RAM and 4 GB of RAM is used to buffer and play music, that is first loaded from the drive. The Ethernet ports are dual-isolated.

This server supports number of file formats, such as:
DSD, FLAC (zero compression), WAV, AIFF, FLAC, ALAC, OGG Vorbis, AAC, MP3 (files are ripped to FLAC or WAV format)
Sampling frequencies:
PCM – 44,1 kHz, 48 kHz, 88,2 kHz, 96 kHz, 176,4 kHz, 192 kHz, 352,8 kHz, 384 kHz
Bit depths – 16, 24 i 32 bits
DSD - DSD64, DSD128, DSD256

The server is also compatible with Internet radio and streaming services, such as Tidal, Quobuz, and so on. As you can see, is an extremely versatile product. It is also possible to use an external file player (renderer), and in such setup ZENith will work only as a server/disk – that's what the second Ethernet port is for.

ZENith connects to the home network using an Ethernet cable, and to the external D/A Converter via USB 2.0 port (hence a comparison to a CD transport). A connection to the home network allows user to control the device and download data for the ripped or uploaded files from the Internet. The files can be uploaded on the internal disc also from an external USB drive (3.0), and the contents of internal library might be backed up on an external drive.

All these steps can be performed by connecting to the server via my.innuos website. It will allow user to see the covers of albums and their description, also editing of these descriptions is possible. It also allows user to decide whether DSD files should be converted to PCM FLAC, or played in their native form. Plus one can change the color of the LED on the front panel of the server :)


To summarize, the server is connected to an audio system using digital USB cable and with a router using Ethernet cable. The former is used to send the decoded PCM or DSD audio signal to an external DAC and the slatter allows user to control the device and to update its database of albums stored on the server.

User controls server using one of recommended applications installed on a smartphone, tablet or a computer. The recommended apps are:

For iOS - iPeng,
For ANDROID – Orange Squeeze,
For WINDOWS – Squeeze Remote.

The prices for these apps are not high, one needs to pay around 25 PLN. There is also one free app available for Android - Squeezer, that seems to work fine but simply doesn't look as good as the above mentioned apps.

Before the test I ripped a few albums using the internal drive and uploaded some hi-res files, including DSD and DSD128, using the USB port. The upload takes some time, but after the first operation, which usually contains large amount of data, each subsequent (smaller) upload should be quite fast. Note that ripping a single CD takes 3 to 5 minutes. The new Naim Uniti Series servers take 1-2 minutes for same action, so as you can see ZENith manufacturer selected a lower speed of reading data from the CD.

The combination of web application and using a portable device as controller brings pretty good results. I learned quite quickly the regime it imposes, although not all the albums were easy to find. The device accurately identifies ripped albums, finding even so rare editions, as the reissues of Proprius label recordings released by Lasting Impression Music.

From user's perspective the ZENith MkII Std. is just a music server, ie. a music files transport integrated with local storage - in this case a SSD. It can also work as a server connected to an external player, but I think that it does not make much sense and it should be used as a complete digital source in a way we use a CD transport.

During this test ZENith was connected, using Curious USB cable to the digital-to-analog converter, Chord Hugo TT and to the input of the CD Player/DAC Cary Audio DMC-600SE. With the latter, unfortunately, I could not play DSD files in native form. Luckily ZENith offers an on-the-fly conversion to 384kHz FLAC, that I could use.

I compared files ripped from CDs directly with the same discs played using the CD transport in Cary Audio. Hi-res files were compared with the same files played with my HP Pavilion dv7 128 SSD + 1TB HDD, 8GB RAM, JPLAY laptop.

I connected the server with router using Acoustic Revive LAN2.0 PL. One could, of course, say that I might have used just any generic cable as it was used only for controlling the device and not to send audio signal, but life teaches us that we should take care of every detail of audio system and so I did. After all, Ethernet is another cable in the system, that acts as an antenna and must therefore be well shielded.

Before I get to the point, let my digress a bit. It is not true that all servers, file players, or whatever name one uses, sound the same, even if it's only a specialized computer that you still need to connect to an external D/A converter. It is not true that in such a setup a DAC is the most important element and files transport should just be convenient and simply functional. It's just silly. And if anyone thinks differently, but only based on what they've learned or read, they are just - please do not be offended, but it's true - ignorant (I refrained myself from using the word 'idiot'). A layman – that I understand, each of us is a layman, because we can not know everything. But ignorant is someone who deliberately does NOT WANT to know, realizing some agenda.

You should listen to the ZENith server (I shall use company's nomenclature) and compare it with another file player and/or a computer. My laptop has been adapted to play files, since it features SSD, and one of the latest versions of the JPlay software player installed personally by Martin Ostapowicz, and I had a chance to use it with dozens of different DACs, so I know it well.

The server under review offers better performance, hands down. In terms of reliability, convenience and sound quality. It happened to me several times that the control application froze and I had to reload it, but I don't even know whether the problem was a communication with the server, or fuzziness of my smartphone. The server itself throughout the test period worked flawlessly and never crashed. Which, after many experiences with computers, was a relief and allowed me to focus on music.

I started with the sound quality – files transports' (ie, servers and streamers without DAC with USB output) performance varies from one to another. ZENith belongs to a group of devices delivering soft, dense, I would dare to say, warm sound. It wouldn't be a problem for me to compare its sonic signature to the one of a nicely sounding turntable or a tube amplifier. I might even say that it is actually its main sonic feature.

Music played by the server is presented in a focused and dense way. Which is a nice change from the rather chaotic presentation served by a large part of the file players and internally "empty" sound of most computers. Even my laptop could not play the 24/192 and DSD files in such a consistent, smooth way as the ZENith. Add to that a very pleasant treble and non-aggressive bass, and it should tell you what to expect from this device. Yes, it is focused mostly on the midrange. Vocals and instruments operating in this part of the range sound really good and are at the center of listener's attention. Particularly rich lower midrange translates into a large volume.

The soundstage is subordinated precisely to that - the information rendered in its center. There is depth, and width, too but only if you really look for it. When listening to this server I never even thought about it. Because it was a pleasant, satisfying presentation. What it comes to music files it is really important and decides whether the device is worth listening to, or it is nothing more but a fancy gadget. The ZENith bases its presentation on colors and harmony, and only then serves the dynamics, range extension and soundstage.

So one could say that somewhat averaged dynamics is its weaker point. Under one condition though, assuming that we are able to sacrifice all that for something else. This device won't offer a very good differentiation. High resolution files sound tonally deeper, there is more of everything (I'm not talking about the details, is not the point) in them, and they simply sound better. But the differences are not that big, because even with CD rips you should get all of what I described. DSD files offer significantly better performance but when using them one has to significantly crank up the volume, which some won't surely like.

The range extremes are at the same time rounded and soft rather than clearly defined. The definition as such was not at all the focus of ZENith's designers. This is obviously a problem with music files themselves (if you think that the files you can buy are the same files that leave mastering studio, you're wrong), but the file players cope with this issue in various ways. The one under review tends to deepen the timbre and combines all elements into a bigger picture. It does not focus on the details, because there is not that many, nor on resolution (ie, information), because it is just OK, but not as good as provided by a CD transport connected to the same DAC.


The strength of the ZENith Mk2 Std. server lies in the fact that any file, regardless of its origin will deliver a competent, consistent performance. It shall work flawlessly and the result (sound) will be predictable. It is also important that CDs ripped using this device do not sound any worse than those that I ripped on my laptop using Exact Audio Copy. If this set of features answers your expectations, if you want to purchase a file player, which is solidly built, won't impose itself with its presence, be sure to listen ZENith paired with a high quality D/A Converter able to decode also a native DSD signal, because these will present the full potential of ZENith.

File player (streamers) and servers are actually microcomputers. And such a specialized microcomputer one finds in the ZENith MkII Std server. One of the main differences between conventional PCs and streamers is that a dedicated software is developed for the latter and all unnecessary (for playing music) functions are turned off. It is not possible in a regular computer. The version we tested uses 8 GB of RAM, and 4 GB is used for buffering the signal read from the SSD.

The second basic element of such a device is power supply. Almost always it is a switching power supply, cheaper and widely available from many companies from the Far East. Innuos designed its own power supply, which could be worthy of a high-end amplifier. Based on the large toroidal transformer it has three separate runs, with Shottky diodes and a very Nichicon capacitors. Diode rectifiers are decoupled using WIMA capacitors in order to reduce the noise generated when switching individual diodes.

And finally, the housing - one of the elements, the importance of which can not be overestimated. The one used for ZENith is made of thick, bent, sheet steel and features a nice, aluminum front. The TEAC CD-ROM is attached to a steel frame, and it connects to the housing via rubber absorbers.

It's solid, pretty job of real aficionados.


Audio outputs: Ultra Low Noise USB 2.0 supporting USB Audio Class 1, USB Audio Class 2 and DoP
• 2x isolated RJ45 Gigabit Ethernet - LAN and Streamer connection
• 1x VGA (for service connection only)
• 1x USB 2.0 (DAC), 1x USB 3.0 (Backup)

CD Ripping
Disc compatibility: CD, CD-R, CD-RW
Audio format for stored CDs: FLAC (zero compression), WAV
Audio formats supported for streaming and playing:
Supported sampling rates:
PCM – 44.1, 48, 88.2, 96, 176.4, 192, 352.8, 384kHz
Supported bit depths – 16, 24 and 32 bits
DSD - DSD64, DSD128, DSD256
Web Browsers for iOS, Android (4.0 and up) Windows and OS X

Hard drive: 1TB Samsung EVO SSD
CPU: Intel Quad Core 2 GHz
Compatible Music Systems: 
Sonos Multi-room Wireless Music System
Naim Mu-so Multi-room Wireless Music System
Denon HEOS Multi-room Wireless Music System
Squeezebox Multi-room Wireless Music System
Naim Uniti
Linn DS
Pioneer N50A
Cambridge Audio CXN
Denon 720AE
Power consumption: 10W, max. 15W
Dimensions: 70 x 420 x 320mm (W x S x G)
Weight: 9kg



- Turntable: AVID HIFI Acutus SP [Custom Version]
- Cartridges: Miyajima Laboratory KANSUI, review HERE | Miyajima Laboratory SHILABE, review HERE | Miyajima Laboratory ZERO (mono) | Denon DL-103SA, review HERE
- Phono stage: RCM Audio Sensor Prelude IC, review HERE

- Compact Disc Player: Ancient Audio AIR V-edition, review HERE

- Line Preamplifier: Polaris III [Custom Version] + AC Regenerator, regular version review (in Polish) HERE
- Power amplifier: Soulution 710
- Integrated Amplifier: Leben CS300XS Custom Version, review HERE

- Stand mount Loudspeakers: Harbeth M40.1 Domestic, review HERE
- Stands for Harbeths: Acoustic Revive Custom Series Loudspeaker Stands
- Real-Sound Processor: SPEC RSP-101/GL
- Integrated Amplifier/Headphone amplifier: Leben CS300XS Custom Version, review HERE
- Headphones: HIFIMAN HE-6, review HERE | HIFIMAN HE-500, review HERE | HIFIMAN HE-300, review HERE | Sennheiser HD800 | AKG K701, review (in Polish) HERE | Ultrasone PROLine 2500, Beyerdynamic DT-990 Pro, version 600 - reviews (in Polish): HERE, HERE, HERE
- Headphone Stands: Klutz Design CanCans (x 3), review (in Polish) HERE
- Headphone Cables: Entreq Konstantin 2010/Sennheiser HD800/HIFIMAN HE-500, review HERE

- Portable Player: HIFIMAN HM-801
- USB Cables: Acoustic Revive USB-1.0SP (1 m) | Acoustic Revive USB-5.0PL (5 m), review HERE
- LAN Cables: Acoustic Revive LAN-1.0 PA (kable ) | RLI-1 (filtry), review HERE
- Router: Liksys WAG320N
- NAS: Synology DS410j/8 TB
System I
- Interconnects: Acrolink Mexcel 7N-DA6300, review HERE | preamplifier-power amplifier: Acrolink 8N-A2080III Evo, review HERE
- Loudspeaker Cables: Tara Labs Omega Onyx, review (in Polish) HERE
System II
- Interconnects: Acoustic Revive RCA-1.0PA | XLR-1.0PA II
- Loudspeaker Cables: Acoustic Revive SPC-PA

System I
- Power Cables: Acrolink Mexcel 7N-PC9300, all system, review HERE
- Power Distributor: Acoustic Revive RTP-4eu Ultimate, review HERE
- Power Line: power cable Oyaide Tunami Nigo (6m); wall sockets 3 x Furutech FT-SWS (R)
System II
- Power Cables: Harmonix X-DC350M2R Improved-Version, review (in Polish) HERE | Oyaide GPX-R (x 4 ), review HERE
- Power Distributor: Oyaide MTS-4e, review HERE
- Stolik: SolidBase IV Custom, read HERE/all system
- Anti-vibration Platforms: Acoustic Revive RAF-48H, review HERE/digital sources | Pro Audio Bono [Custom Version]/headphone amplifier/integrated amplifier, review HERE | Acoustic Revive RST-38H/loudspeakers under review/stands for loudspeakers under review
- Anti-vibration Feets: Franc Audio Accessories Ceramic Disc/ CD Player/Ayon Polaris II Power Supply /products under review, review HERE | Finite Elemente CeraPuc/ products under review, review HERE | Audio Replas OPT-30HG-SC/PL HR Quartz, review HERE
- Anti-vibration accsories: Audio Replas CNS-7000SZ/power cable, review HERE
- Quartz Isolators: Acoustic Revive RIQ-5010/CP-4

- FM Radio: Tivoli Audio Model One