DAC manufacturers and their marketing departments like to KISS: to keep it simple, stupid. Their DAC’s clock and data buffers will eradicate any jitter. USB port galvanic isolation and/or internal power supplies will minimise electrical noise disturbances. The implication is that said DAC’s sound remains independent of source; any PC/Mac/streamer will do.
It’s a nice idea – but reality tells us that the romantic appeal is short-lived. Experience debunks the theory to show us first hand that no two digital sources sound alike. A Raspberry Pi 3’s USB output sounds thin and emotionally distant. A Macbook Air doesn’t fare much better. In 2017 we’ve learnt that the Sonore microRendu and ALLO DigiOne sound better. The ultraRendu better still.
Drawing parallels with the vinyl world, a DAC is analogous to a phono pre-amplifier whilst the source device (PC/Mac/streamer) stands in for the turntable itself. Each part of the chain influences the audible outcome. Experience tells us what theory-fixated armchair pundits cannot: that everything matters.
Patching our Dells, our Apples and our ‘Pis with aftermarket audiophile fixes — often a combination of specialist playback software, USB de-crapifiers, USB-S/PDIF converters and audiophile-grade USB cables — only takes us so far.
To move beyond this glass ceiling we look to bespoke solutions – streamers and servers designed to lower jitter and quiet electrical noise from the outset and not downstream, after the fact.
One such manufacturer is Portugal’s Innuos who offer up their Zen Mini (€849) as a direct digital audio challenger to Apple’s Mac Mini whilst also adding TEAC-powered CD ripping possibilities, long since ditched by Cupertino.
Those with a theoretical allergy to the Zen Mini’s switch mode power supply might look to the Zen MKII (€1799+) or Zenith MKII (€2699+) whose linear power supplies, ‘medical-grade’ mains filters and vibration damping promise to take sound quality higher still.
Aiming for the top floor and limited to 100 pieces – hello FOMO – Innuos launch an all-out assault on electrical noise and jitter with the Zenith MKII SE. A 2TB SSD comes fitted as standard for €5699. An XL version doubles that internal storage to 4TB to ring the register at €7699. That’s some hefty wallet damage. This isn’t Kansas no more.
In lifting the Zenith MKII SE from its foam-cheeked double boxed packaging we encounter serious heft a second time: say hello to 11kg. From the bottom shelf of my Hifi Racks’ Podium Reference rack, the Innuos’ sculpted front panel connotes low-profile CD player. An asymmetrically aligned trio of anti-vibration feet on the server’s underside tick another audiophile-centric box.
Popping the Zenith MKII SE’s lid only adds to the audio component vibe: a large toroidal transformer with “custom-built GOSS band” (for EMI shielding) feeds three Mundorf capacitor-loaded linear power supplies than in turn juice: 1) a Samsung EVO SSD; 2) an Intel Quad Core 2GHz CPU (directly) and; 3) a motherboard loaded with 8Gb of DD3 RAM, half of which is set aside for playback buffering of internally stored music.
According to Innuos Director Nuno Vitorino: “The SSD and CPU are the noisiest components so the system benefits a lot with them being separately powered as it helps them not to contaminate other components.”
He continues: “The larger transformer isn’t about reducing noise but essentially to reduce impedance on the PSU as it can fill up the capacitors quicker. This allows the PSU to provide faster transients to respond to power requirements from the different components. It’s also a much better shielded transformer and reduces high-frequency vibration.”
“The funny thing is that these kind of factors look like they’d make a lot more sense in an amplifier but we have no doubt in my mind that they’re a factor in a digital source too – just compare a Zenith to an SE and you’ll hear it right away.”
“Dr. Sean Jacobs is the genius here. He designed the PSU circuit exclusively for us and it is where math comes in. Too much [transformer] will not make much of an effect and you’ll be adding up just dead weight and adding cost. You need to evaluate the PSU circuit, measure the capacitance and then calculate how many VAs you need for the toroidal.”
Piling on more pounds are the power supplies’ heatsink and anti-vibration treatment, the latter applied to the underside of the unit’s top panel, about which Vitorino says, “It doesn’t only convert vibration into small amounts of heat but adds mass to the chassis to dissipate vibration caused by the sound waves coming from the speakers.”
Digital inputs number one: Ethernet: 1) for updating the InnuOS operating system; 2) for running the server as a Roon Ready or UPnP streamer; or 3) for transferring music from elsewhere on the network to the Zenith MKII SE’s internal storage. I moved a couple hundred gig from Roon Core-d NUC to the Innuos’ Auto-Import folder across the DARhaus LAN without issue. The file import process automatically separates incoming files into cd-quality, compressed and high-res folders – which folder view aside, library indexing ignores – and checks them for tagging/filename problems.
Alternatively, a USB hard-drive plugged into the unit’s other USB port – a 3.0-er and otherwise reserved for backups – would have done the file transfer job in considerably less time.
File transfer and import are handled by the in-house InnuOS operating system, accessible from a web browser and mobile-optimised. A cut above the outgoing Vortexbox (and also Small Green Computer’s SonicOrbiter OS) on user friendliness, the InnuOS user interface is a breath of fresh air, especially for users who aren’t especially tech savvy.
A simple slide-in menu give us access to CD ripping, Roon integration (as Core or as Roon Ready endpoint), library backup and other miscellaneous options.
Vitorino again: “Our goal is also to ensure users can fully manage and play music without the need of a PC/Mac as we see a trend where users are replacing their aging laptops for tablets. By using a web-based responsive interface that adapts to the kind of screen you are looking (be it a smartphone, tablet or computer) we can also maintain full UI consistency between platforms. If you open the innuOS Dashboard on a smartphone, you’ll see the UI layout adapts automatically to the screen – an example is the album editing screen where the layout is more linear than on a tablet. This allows you to even use a smartphone to edit your music library easily – which is great if you just remembered to make a quick change or check the status of a CD ripping, etc.”
“Case-in-point: Standard vs Low-Latency mode for the Music Player. We could build a full UI so you could tweak period, buffer sizes, you name it. And yet, how many users actually know enough to use it properly, particularly as you’ll get some very nasty noises if you do it wrong? So instead, we defined a standard mode that works well with all DACs and a Low-Latency mode, which we tried ourselves on a number of DACS and did improve sound on most (though not all – hence the option). This way you just flip a switch and give it a go.”
“Some people ask us why not rip in AIFF or other additional formats? Because there should be a clear case for it. Currently you can rip in WAV if you want to make sure you get the full uncompressed stream for peace of mind, or FLAC (with zero compression) if you want a more universal format to use with a number of systems. If we get a clear case for including AIFF, then we will. But just adding an option for the sake of it just adds to the whole complexity associated with digital audio.”
“The software is the same as the other Zeniths and in fact the same across the whole Zen line (with some tweaks specifically for each system). We focus on system synergy between the hardware, firmware and software. From the system BIOS and device firmware to Linux Kernel and the sound subsystem, we try to minimise the signal paths and lower power noise produced by the system. An example is memory-playback: when playing through the integrated music player, all music is loaded into 4Gb of dedicated RAM and played directly from there. This keeps SSD access quiet during playback. We configure the SSD controller extensively to limit the amount of noise the SSD can do on the system, helped by the fact the SSD uses its own linear power supply as well as vibration treatment.”
That integrated music player is an open-source Squeezelite client, served internally by Logitech Media Server. Familiar territory for this ex-Squeezebox Touch owner. Here however the Zenith MKII SE puts server AND client under the same roof. No additional network storage required.
LMS remains accessible from port 9000 for those who want to tweak and otherwise remains out of sight. Spotify, Tidal and Qobuz account logins are configured from within the MyInnuOS’ system settings page. Upon the click of save, usernames and passwords are handed off invisibly to the corresponding plugins living in the LMS back-end — a nice touch.
InnuOS allows us to run Roon two ways: 1) with the Roon Core server and Roon Ready client software both running on the Innuos sever or; 2) as Roon Ready endpoint playing catch on streams dispatched from elsewhere on the home network.
Digital outputs number one: an ‘ultra low noise’ 32bit/384kHz DSD128-capable USB 2.0 port for, in my case, PS Audio DirectStream (Huron OS) DAC…
…or two if we count the low-noise Ethernet passthrough port to which one can directly connect a third party Roon Ready / UPnP streamer. It’s a thoughtful touch but I failed to discern any real audible gains in applying the Innuos’ low noise Ethernet passthrough to the already impressive Wyred 4 Sound-modded Sonos Connect. I might have heard a little more body and less glare from the PS Audio Network Bridge II but I couldn’t swear on it.
The remainder of this initial test system comprised Schiit Vidar power amplifier and Schiit Saga preamplifier (joined via Curious interconnect) and KEF LS50 loudspeakers hooked into the Vidar with AudioQuest’s Rocket 88 loudspeaker cable. USB cable duty was handled by Curious. AudioQuest Yukon sat between DAC and preamplifier.
I started my listening with the Zenith MKII SE as a Roon Ready endpoint with Roon Core running on an Intel NUC. In this context, the Innuos box offers more audible weight and substance than even the Sonore ultraRendu.
The Portugese fella exposes more connective tissue and (an even!) greater sense of ease to LCD Soundsystem’s American Dream without surrendering detail or liquidity offered up by the Wyred 4 Sound-modded Sonos Connect. It’s a move from skimmed to full cream milk where flavours kick a little harder. The Innuous also bests the Sonore on dynamics, both micro and macro.
Relocating Roon Core duties to the Innuos server adds another dollop of fat but the best result overall I’d give – in a pinch – to the integrated Squeezebox player. With weaker 80s recordings like The Smiths The Queen Is Dead we note more bone density, even when spinning this year’s tidied up Deluxe Edition.
In teasing out the nature of the Zenith MKII SE’s fingerprint we take note of what is added – acoustic mass and a drop of honey – but also what is taken away – a subconscious-distracting lower treble glare that’s often not remarked upon until it is wiped away.
Sharpening our descriptive pencil whilst running back and forth through new EPs from Blawan (Nutrition) and Floating Points (Ratio), the Innuos box lowers music’s center of gravity, puts a stripe of eye-black beneath each ear’s ‘inner eye’ and imbues IDM/techno’s rhythmic tension with a yielding pliability that I’d hoped my Technics SL-1200G turntable would realise with its Zu DL-103R MKII pickup.
The benefits for the listener are two fold: greater audible ease relaxes the shoulders; a reduction in glare lowers the head. The resulting better posture translates to better breathing – less from the chest, more from the stomach – and therefore renders music physically more enjoyable, albeit subtly so.
Audiophiles live in a world of ever decreasing marginal returns. Digital audio deltas are small by nature. It is a reviewer’s job to amplify them in order to tease out their qualitative differences. The flagship Innuos introduces us to more acoustic heft from the PS Audio DirectStream DAC – our third encounter with that H-word – than heard from Sonore’s ultraRendu.
This is where things get really interesting. The now Roon Ready PS Audio Network Bridge II that ordinarily feeds my DirectSteam DAC has seen real world experience consistently jive with the theoretical advantages of a I2S-direct connection to the host DAC’s intestines. No third party USB- and S/PDIF-transmitting streamer has ever bettered it…until now.
Compared to PS Audio’s plugin card, the Innuos Zenith MKII SE removes hitherto unnoticed glare and adds body to shift tonal balance on the Kraftwerk-aping Car Car Car by DJ Hell ever so slightly downwards. Evidence that this DAC still has more to give.
A similar story played out with Devialet’s Expert 200 where performance delta daylight between the mirrorbox’s Roon Ready Ethernet input and the Zenith MKII SE (running as a Roon ready streamer) was even wider. The Devialet all-in-one really benefits from an uptick in audible richness wrought by the Innuos box.
Similarly, the KEF LS50 Wireless whose acoustic mass clicks a few percent northwards once lassoed to the Zenith MKII SE with Curious USB cable. This compared to its own Roon-infused Ethernet input.
Mirroring Innous’ demo system as seen at the Norddeutsche Hifi-Tage back in February 2017, I now clearly understand why Vitorino and co. showed their Zenith MKII server with the KEF system-in-a-box. An arrestingly simple rig whose per component spend falls heavily in favour of the source first approach and comes out shining.
This streamer/server turns conventional thinking – that nothing can beat a digitally direct signal path – on its head.
The Zenith MKII SE exposes more of music’s DNA to give a fuller picture that builds further with connective tissue and skin surfaces on the comparatively skeletal outline delivered by lesser (and less costly) boxes. Whether this is the best sounding server out there for the money we cannot know. You might find alternatives with VU meters or S/PDIF output more to your liking.
Innuos’ limited edition flagship server shows us that considerably more is possible from digital sources once the bean counters are sent packing, the engineer is given free range on build budget and our spend turns from hundreds into thousands.
The InnuOS software extends both hands to the beginner computer audiophile who wants no part in the digital audio journey. For set-and-forgetters, this is a turn-key solution that’ll get anyone up and running with a high-end digital audio sound in a matter of minutes and – often overlooked – with next to no digital audio knowledge. This server connotes more appliance than computer.
For the more seasoned digital audiophile caught between a streaming rock and a D/A converting hard place, know this: starting over with ten grand to spend, I’d take this Innuos and drop whatever cash I had left on a lesser DAC instead of putting the larger percentage of my dollars into a better D/A converter only to feed it ones and zeroes by a standard PC or Mac.
The Zenith MKII SE is as good an example as any that one must spend big, as in vinyl land with turntables and cartridges, to more fully realize the potential of digital audio; and for sound quality to transcend its transmission medium. Pair the Zenith MKII SE with even a modestly-priced DAC and feel the upgrade itch slowly dissolve as you sink back into your listening chair and exhale a pleasurable sigh of relief as music’s tension – and therefore your own – falls away.
Further information: Innuos