• SOtM sMS-100 Mini Server Review

    Have a good USB DAC? Check. Want to turn it into a networked device without changing one item on the DAC? Check.

    Over the last couple years I increasingly wanted a specific product that didn't exist. I wanted an ultra simple device with Ethernet input and USB audio output. This seems like such an obvious product that should have been available since the day the first USB DACs hit the market. Especially because so many of the network addressable DACs have big problems with file types, compression schemes, gapless playback, etc… Plus, if the sound of a specific USB DAC is what the listeners want, but they also want the functionality of a networked DAC, they should be able to bridge the gap. This isn't rocket science and this isn't the 1980s. Tiny ARM based Linux compatible single board computers are everywhere. It's time for the Internet of Things and running on this IoT are millions of tiny devices that can be used to create a simple Ethernet in and USB audio out device. As The O'Jays, The Kinks, and Sharon Jones & the Dap-Kings said, Give the People What They Want. Thus, the SOtM sMS-100 Mini Server was created. We finally have a physically simple device that converts network audio streams into USB audio streams for playback on nearly any popular USB DAC.

    What Is It?

    In ultra layman's terms the SOtM sMS-100 Mini Server is an Ethernet to USB converter. Plug it in to a network on one side and a USB DAC on the other side. This sounds simple enough for most people to get the essence of the sMS-100. The "inside baseball" details involved with this Ethernet to USB converter will be covered later.

    The SOtM sMS-100 Mini Server is a very versatile in that it that enables the listener to stream audio through the device to a USB DAC using one of several methods. The sMS-100 supports USB Audio Class 2.0 compliant DACs as well as DACs from Chord, Mytek, and the M2Tech HiFace 1 & 2. Only one streaming method can be used at a time, but the listener can switch to any of the other methods very easily. For example, the listener can start using AirPlay then switch to use UPnP / DLNA with a couple mouse clicks.

    SqueezeLite - When set to this mode the sMS-100 receives audio from any Logitech Media Server (LMS). LMS can be installed on any computer and most NAS drives, enabling listeners to stream from a Mac, PC, or even straight from the NAS without a traditional computer "middle man". This configuration essentially turns the sMS-100 into a modern Squeezebox replacement. iOS apps such as iPeng 7 can be used to browse an LMS library or Internet radio service and stream the audio directly to the sMS-100 for output to a USB DAC. Gapless playback of FLAC, ALAC, WAV, and AIFF is supported. DSD is supported in combination with Vortexbox 2.3 or newer, Daphile, or a custom version of LMS for Mac.

    AirPlay - In this mode the sMS-100 looks like an Apple AirPort Express to any audio device that supports AirPlay. These devices such as an iPhone, iPad, and computer running iTunes can stream directly to the sMS-100 the same way audio is sent to an AirPort Express. Selecting the sMS-100 as the audio end point is done via the identical process as selecting an AirPlay speaker or other AirPlay device.

    UPnP / DLNA - In this operating mode the sMS-100 turns into a UPnP / DLNA Renderer. Listeners can use their favorite UPnP / DLNA server such as JRiver Media Center, MinimServer, Asset UPnP, or any number of apps built-in to NAS drives from Synology, QNAP, or Thecus. In addition, the selection of a UPnP / DLNA control point (remote control) is wide open to the listener. PlugPlayer is one iOS option with some limitations while BubbleUPnP is a solid Android based option. JRemote is a solid option used in conjunction with JRiver as the media server. Gapless playback of FLAC, ALAC, WAV, and AIFF is supported as well as DSD / DoP when using a DoP compliant server such as MinimServer and JRiver Media Center. I've been told Audionet is a good option for iOS as well, but can't verify it at this time.

    MPD - This is a unique mode that requires the use of a Vortexbox based music server from companies such as Sonore, SOtM, and Wyred 4 Sound. The sMS-100 functions as an MPD player, but has the ability to find music stored on a Vortexbox automatically over the network. Both PCM and DSD are supported. Gapless playback of FLAC, ALAC, WAV, and AIFF is also supported.

    HQ Player NAA - This mode works in combination with the Sygnalyst HQ Player application. HQ Player is an advanced application capable of serious DSP. The app is a bit complex for most computer audiophiles. Nonetheless the sMS-100 can accept network audio streaming from the app.

    The SOtM sMS-100 Mini Server runs Fedora Linux as its operating system. Software named Sonic Orbiter, created by Small Green Computer, and licensed to SOtM, is what makes the sMS-100 special. Sonic Orbiter is a combination of open source and proprietary software that enables seamless switching between the aforementioned audio modes, and the ability for the sMS-100 to find networked music on a Vortextbox automatically. The selectable audio modes enable the sMS-100 to support various playback schemes supporting PCM and/or DSD with several file formats at several sample rates. In other words, Sonic Orbiter is the secret sauce of the SOtM sMS-100 Mini Server.

    Note: I've been working with small ARM based single board computers for years. I know exactly what it takes to create a product such as the SOtM sMS-100 Mini Server with Sonic Orbiter software. Getting such a device most of the way toward working is the easy part. Perfecting the device to support all relevant sample rates, file formats, gapless playback, without sonic dropouts, and third party USB drivers is no simple task. I mention this because invariably some readers will insist that a device like the SOtM sMS-100 Mini Server can be built easily by someone with a little Linux knowledge. In my experience getting a device to work this well is not an easy task.

    Why The Need?

    The need for an Ethernet to USB audio device is obvious to some and lost on others. This need came about for several reasons. First, the market for USB DACs has exploded and listeners want to take advantage of these DACs in every way possible. Second, an add-on device like the sMS-100 increases choice for consumers looking for a USB DAC with a specific sound or set of features. Third, high performing audio components with built-in Ethernet capability, like Linn, T+A, and dCS, have traditionally been much more expensive than USB DACs, plus many other expensive streamers use the same internal card from Stream Unlimited. That card brings us to the fourth reason, reliability and functionality. Many network capable devices like the Musical Fidelity M1 CLiC and PS Audio Perfect Wave Bridge have been fraught with streaming issues. Many network DACs, especially early builds, had issues leading consumers to steer toward USB DACs. That's a brief, but not exhaustive view of how we got here and why the SOtM sMS-100 Mini Server is a solution for a real audio need, not a solution looking for a problem.

    The SOtM sMS-100 Mini Server In Use

    The SOtM sMS-100 Mini Server isn't a complete end-to-end solution. It's simply an end point or renderer that requires a server and remote control app. During the review period I tested all kinds of apps and servers using both UPnP / DLNA and Logitech Media Server (LMS). I prefer to go the UPnP / DLNA route over the LMS route because I like the server and remote control interface options much better. To be 100% honest, I'm not a big fan of LMS. But, I do understand the platform has a really large following and I can't argue with people's preferences.

    The configuration I used for most of the review period was a Synology DS1812+ NAS for music storage, a Windows 8.1 PC running JRiver Media Center as the DLNA server and music library curation application, and JRemote to browse and select music from an iPad. Once the SOtM sMS-100 Mini Server is connected to the network, with DLNA enabled, it appears automatically as a zone in JRiver / JRemote. Each additional SOtM sMS-100 device added to the network appears as a separate zone and JRemote has complete independent control over these zones. The sMS-100 is a very smart dumb device. Once DLNA is selected there is nothing else a user needs to configure on the unit. It acts like a "dumb" Ethernet to USB audio converter. However, the software inside the sMS-100 is far from dumb.

    I like to test devices like the sMS-100 not only by streaming all types of audio, but also by connecting and disconnecting DACs and pulling the power cable when I probably shouldn't cut the power. There wasn't a single thing I could do to make the sMS-100 malfunction. I started playing music with the EMM Labs DAC2X connected. I wanted to try the Berkeley Audio Design Alpha USB so I stopped playback, like any normal person would do, plugged the USB cable in to the Alpha USB, then pressed play. Playback commenced immediately. The sMS-100 didn't skip a single byte or bit. Many servers on many operating systems would struggle with this USB audio device swap and would require user intervention. There was no such issue with the sMS-100. I get that most users will have a single DAC and have no interested in hot swapping DACs. However, I described this test as an indication of the sophistication of the sMS-100 and Sonic Orbiter software.

    Testing audio playback with a handful of difficult or problem tracks also displayed no weakness in the sMS-100. I sent 24 bit / 192 kHz gapless tracks, high resolution tracks with multi-megabyte album art, gapless DSD, compressed and uncompressed FLAC without identifying a single issue with the sMS-100. The sMS-100 performance in this area is much like the Lumin DLNA player. The similarity between both devices is that they handle all the network audio functions with Linux based software. The major differences between the devices are functionality and price. The Lumin is a full featured DLNA renderer with DAC and iOS app for around $7,000 and the sMS-100 is a much simpler device with less functionality for $450.

    The sound quality of music played through the SOtM sMS-100 Mini Server had three distinct levels, good, better, and great. But, not all levels were present while connected to all DACs. For example, when connected to a completely isolated USB audio device such as the Alpha USB or Ayre Acoustics QB-9 the sMS-100 was only capable of great sound. The other levels of sound quality were present with unisolated devices, and depended on use of the SOtM mBPS-d2s Intelligent Battery Power Supply ($399).

    Listening through the sMS-100 connected directly to the EMM Labs DAC2X via USB the sound quality was good. Most of my rock and roll tracks from Pearl Jam, The White Stripes, and new 2014 Led Zeppelin 24/96 remasters had no sonic issues. When listening to Perfect Sense, Part I on Roger Waters' Amused To Death album I noticed the soundstage was reduced quite a bit from what I'm used to hearing in my system. This album features Q Sound. The voices in the begin of Perfect Sense, Part I should emanate from the far left while the piano should emanate from the far right. It's an enveloping sound when done right. In this configuration the voices barely reached outside the left side of the left speaker and the Piano wasn't nearly as far right as it should have been. Switching to Shelby Lynne's track Like A Fool, I noticed a little lack of resolution and my inability to place the instruments and vocals exactly in their familiar positions. The sound was running together a bit.

    In addition to receiving the sMS-100 I received the SOtM mBPS-d2s battery supply to try if I was interested. I initially planned on skipping the battery supply for this review. However, I had a gut feeling that the sonic impurities I heard we related to electrical noise. I connected the sMS-100 into the mBPS-d2s battery supply and played the same tracks through the identical system. The sound quality was quite a bit better. It was easy to hear the soundstage widen while listening to Perfect Sense, Part I and better delineation of the instruments in Like A Fool. This was a very positive improvement. But, sound quality wasn't as good as it would get with the sMS-100.

    Testing my theory a bit more I connected the sMS-100 without the battery supply to a Berkeley Audio Design Alpha USB converter that converts USB to AES. This converter has the best isolation of any converter I've ever used. The setup was USB out of the sMS-100 in to the Alpha USB, and AES out of the Alpha USB and in to the EMM Labs DAC2X. Playing the same tunes I immediately noticed my music come to life. The ultra wide sound stage of Q Sound and the delicate backing instruments of Shelby Lynne's band were right there in front of me. This was the sound I was searching for from the sMS-100. Continuing the evaluation I placed the mBPS-d2s battery supply back in the chain to power of the sMS-100 while still connected to the Alpha USB. This made absolutely no sonic difference. Based on this little unscientific experiment I concluded the USB output of the sMS-100 with its standard switch mode power supply is probably a bit dirty, but there are viable remedies to improve performance greatly.

    Logitech Media Server isn't normally that intriguing to me because I like the alternatives much better. However, there's one development that changes things a little bit. After a recent trip to Munich's high end audio show and my discussions with the team from WiMP, I rigged LMS to stream lossless 16 bit / 44.1 kHz music from WiMP's HiFi service in Norway and controlled playback from my iPad using the iPeng 7 app. It wasn't the ideal solution, but it enabled me to stream from a collection of over twenty million bit transparent lossless tracks. In the coming months and years there will be several variations of this type of system that enable streaming lossless CD quality and higher resolutions. I enjoyed WiMP through LMS, but moved away from it eventually because the iPeng 7 interface with WiMP leaves a bit to be desired (the same can be said for the official Logitech iOS app) and the WiMP / Sonos interface). While in Munich I talked to a couple people who used this exact setup WiMP / LMS / iPeng 7 and they were completely satisfied with the interface. Again, I can't argue with people's preferences.


    Streaming via DLNA, LMS, AirPlay, NAA, and even from lossless cloud based services through the SOtM sMS-100 Mini Server is terrific. Audio isn't a one size fits all hobby. Some people love Logitech Media Server while others prefer DLNA streaming. Yet others prefer to stream podcasts from iTunes via AirPlay to the sMS-100 then switch to DLNA for the serious stuff. The sMS-100 makes all of these use cases possible and simple to execute with excellent reliability. Great sound quality is possible through the sMS-100, but may be dependent on one's DAC, USB audio interface, or even the relatively inexpensive SOtM mBPS-d2s Intelligent Battery Power Supply ($399). Computer audiophiles interested in the new Auralic Aries ($1000-$1600) should consider the already-available SOtM sMS-100 Mini Server at less than half the price. Based on its great performance for a relatively small price and the fact that this product fills a huge hole in our wonderful hobby, the SOtM sMS-100 Mini Server is CASH Listed.

    Product Information:

    • Product - SOtM sMS-100 Mini Server
    • Price - $449, (optional SOtM mBPS-d2s Intelligent Battery Power Supply - $399)
    • Product Page - Link
    • User Manual - Link (PDF)

    Where To Buy

    Associated Music:

    Associated Equipment

    Comments 128 Comments
    1. firedog's Avatar
      firedog -

      Realy intriguing review.

      I especially liked the little experiment you did with the SOtM battery supply and using the Berkeley converter as an isolator to compare.

      I wonder if there is any other device on the market that could do what the Berkeley did for less.

      I'd suggest that when you review the Aries you do the same kind of experiment, and the results may help us learn if the Aries is worth twice the price (or more) of the SOtM unit.
    1. tranz's Avatar
      tranz -
      Thanks for the review. I would love to see the technical details follow up.

      I.e. no graphics chip, limited hardware mobo, SoTM usb card, small power fluctuations, minimal background processes, option for external LPSU, etc.?

      Could this be the audio server answer in a 2 server (control and audio output) setup? Can the control server be either Mac or Win based?

    1. MarkS's Avatar
      MarkS -
      Great review of an intriguing product. Can't wait for the Aeries review.

      I'm nervous about the quality of the Aries' PSU. And I don't mean that as a slight against the Company, especially since the product isn't even out yet. I only mention it because PSU's are so critically important to the ultimate sound. I hope the PSU is of a super high quality.
    1. labjr's Avatar
      labjr -
      Is it better than using a notebook computer?
    1. tranz's Avatar
      tranz -
      Hi Chris,

      With the Alpha converter and/or battery does the sound with the SMS100 beat or match the Aurender W20, ignoring all the extra features of the W20 for a moment?

      Is your control computer optimized for low electrical noise? Was there an ethernet filter in place?

    1. The Computer Audiophile's Avatar
      The Computer Audiophile -
      Quote Originally Posted by labjr View Post
      Is it better than using a notebook computer?
      Only you can answer that question.
    1. labjr's Avatar
      labjr -
      I'm beginning to wonder if replacing one computer with another one makes any difference?
    1. The Computer Audiophile's Avatar
      The Computer Audiophile -
      Quote Originally Posted by labjr View Post
      I'm beginning to wonder if replacing one computer with another one makes any difference?
      Only you can answer that one as well :~)
    1. realmassy's Avatar
      realmassy -
      Thanks for the nice review, Chris. I've been using the mini server for a few weeks and I'm loving it. In my system, to my ears etc etc sounds better than my previous PC + JPlay, and I use the Ayre QB-9, which as you mentioned in the review is completely isolated. Actually I've built a USB cable whithout the power line at all (so not just a dual head USB) and it works perfectly with the mini server. I was waiting for the Aries but I was concerned about the integration with JRiver/JRemote.
    1. wappinghigh's Avatar
      wappinghigh -
      What a superb review Chris. The time taken and detail show you really "get this" streaming stuff!!!

      And so does Sonore. Clearly. Because they have had this, and the Rendu out there for months...if not years..

      Chris I have a couple of Q's..

      1/ You said you couldn't stop this product from working (power disconnects etc) Can you see say 4 of these all networked and joined together fully functional in a multiroom setup (like say Sonos)

      2/ Do you think the Mini Server will work with *every* USB connection/DAC come what may (or does it have driver compatibility issues rumoured to be in the Aires)

      3/ Why do you think Sonore doesn't release a version with SPDIF out to compete with the Aires? Or could this be coming as well?


    1. juno's Avatar
      juno -

      You wrote : " In addition to receiving the sMS-100 I received the SOtM mBPS-d2s battery supply... The sound quality was quite a bit better...This was a very positive improvement. But, sound quality wasn't as good as it would get with the sMS-100."

      Sorry but I don't get it well, last sentence especially, could you please clarify if SQ was better with or without the battery power supply ?


    1. CKKeung's Avatar
      CKKeung -
      Quote Originally Posted by firedog View Post

      I especially liked the little experiment you did with the SOtM battery supply and using the Berkeley converter as an isolator to compare.
      I wonder if there is any other device on the market that could do what the Berkeley did for less.
      Schiit Audio will launch the Wyrd which clean up noise and stablize the DC of USB soon. Price low and worth considering.
      Five new pieces of Schiit drop at T.H.E. Newport Beach 2014 | Digital Audio Review by John Darko
    1. kumakuma's Avatar
      kumakuma -
      Quote Originally Posted by CKKeung View Post
      Schiit Audio will launch the Wyrd which clean up noise and stablize the DC of USB soon. Price low and worth considering.
      Five new pieces of Schiit drop at T.H.E. Newport Beach 2014 | Digital Audio Review by John Darko
      Gotta love the title of this article...
    1. Sam Lord's Avatar
      Sam Lord -
      Nice work, thank you Chris.

      I have the unit and the BPS, but because of equipment location and the excessive USB cable length required, I won't be able to test the sonic insertion loss. Did you, or would you, test the unit in the circuit compared to outside the circuit, i.e. using the same USB cable? Of course it's not quite the same because another ethernet connection is added in the computer-to-SMS100 leg, but the comparison is important, IMO.

      Also, critically, the unit has a selectable option for use as an HQPlayer NAA (server) capable of DSD256 output. But AFAIK there is no DAC that now operates *with* HQPlayer at that speed. I believe Exasound is working to provide that ability. Can you shed any light on the situation? BTW my system is almost rebuilt but like you I'll begin by using JRiver's DLNA setup.
    1. 4est's Avatar
      4est -
      Out of curiousity Chris, did you try the sMS 100 with two USB DACs attached? If so, can you pick one, or does it automatically switch or something?

      Does anyone know if you can hack(DIY) i2s out of this? I'd buy one in a heartbeat if so... Are there any photos of the interior?
    1. One and a half's Avatar
      One and a half -
      Quote Originally Posted by labjr View Post
      I'm beginning to wonder if replacing one computer with another one makes any difference?
      That's a good point, this focuses on the level of computing/processing that needs to get the job done. Is a small renderer better than a full computer, not necessarily. Let's put aside more processing = more noise for now.

      The sMS-100's sound quality is as good as the power supply that feeds it, so there is a limitation that requires work and thought. The battery supply is one solution, independent PSU could/would make a lot of difference as well. As to how much, it's subjective, but if you do have a good PSU (JS-2, Pardo, Hynes), then its use would be mandatory with the sMS-100 or similar.

      Inside the sMS-100 is a computer, obviously scaled down from your regular Mac Mini/CAPS designs, but the computer as a music server is, still, inherent in its design, uses less connections and more importantly less reliance on external power supplies to get to the DAC where quality is critical, that is out of the USB port. In a typical scenario using an Ethernet Renderer:

      NAS + PSU (Maybe int or ext) -> Switch/Router -> Ethernet -> Renderer + Ext. PSU -> USB A to USB B Cable -> DAC (Add a computer to manage the files anyway)

      Compared with

      DAS + Ext. PSU -> USB/FW/TB cable -> Computer -> USB A to USB B Cable -> DAC or
      NAS + PSU (Maybe int or ext) -> Switch/Router -> Ethernet -> Computer -> USB A to USB B Cable -> DAC

      The big IF is that the DAC you use couldn't care less about noise from the source, since it takes corrective action internally, then the choice of using a renderer is dependent on the install (long cabling). If the DAC doesn't, in fact uses the 5V from the computer, then it would be wise to use the least amount of devices in front of the DAC as possible.

      All these PSUs in the chain, complicate AC ground loops and stray noise conductive paths, less of them and the wall warts, the better.

      I must be in the camp where I can't see the use of a renderer, where a 'classic' Computer/USB/DAC works consistently and with repeatable SQ expectations.
    1. wappinghigh's Avatar
      wappinghigh -
      ^ it's all about ease of use...

      Chris made that point in his plug/unplug/pull the power comments..
    1. The Computer Audiophile's Avatar
      The Computer Audiophile -
      Quote Originally Posted by labjr View Post
      I'm beginning to wonder if replacing one computer with another one makes any difference?
      Fortunately these renderers running Linux work like an appliance. They do one thing and have nothing a user can screw up or maintain.
    1. Sam Lord's Avatar
      Sam Lord -
      I wish I could have done the following tests on my SMS100, but they would have been extremely difficult to set up and would have been incomplete:

      1) Does it improve or degrade sound quality? Obviously this depends on the system.

      2) Is there any way to use the HQPlayer option and hear DSD256?

      EDIT: Ahh, there is a DIY DAC By Miska:

      Signalyst DSC1

      Hopefully new DACs that do this will come along.

      Hacking i2s seems like an amazingly silly project to attempt, but maybe I'm wrong.
    1. Superdad's Avatar
      Superdad -
      Yes, and low activity on the processor module and lack of storage interface interference are in the plus column for a small "renderer."
      Such a device is also an opportunity to develop a high-quality, isolated USB output to feed the DAC with. Though I have no knowledge of the extent to which SOtM focused on that, given their popular PCIe USB card I doubt they overlooked it.

      I'm not a big fan of DLNA, LMS, etc. (though I respect those who are). But I would be very interested in trying the sMS-100 as an NAA for Miska's (Signalyst) HQPlayer.