SOtM sMS-200 Review

The SOtM sMS-200 is one of the more popular products on the market in the Ethernet to USB category. A category that was pretty much created by the team at Sonore with its early products and the release of the microRendu. Ethernet to USB devices are now the 'it" products. More manufacturers are copying these idea and features, to implement them in products at all price levels.

At its most basic level, the sMS-200 is a digital to digital converter. Ethernet packets in and USB packets out. I guess it's even possible to consider the device a protocol adapter, from TCP data packets to USB data packets. The sMS-200 is great for people with USB DACs or even more traditional DACs without USB or Ethernet inputs. In the case of a USB DAC, a direct connection between the sMS-200 and the DAC is made by a single cable. Other DACs will require a USB to S/PDIF converter to sit between the sMS-200 and digital to analog converter.

If all this sounds like a lot of converters and boxes and potential problems, it really isn't an issue for the most part. A larger problem is replacing a DAC that one paid thousands of dollars for, just because it isn't RoonReady or doesn't support Ethernet input. Devices like the sMS-200 open a whole world of possibilities for any USB DAC, and save one's investment in whatever DAC he or she already owns.

With respect to hardware, the sMS-200 appears to be a ground-up SOtM design. It features an ARM processor on a custom motherboard that's typical SOtM white in color. On the inside, the device looks very similar to one of the popular SOtM USB cards that many in the Computer Audiophile community have used for years.

Digging deeper into the software running on the sMS-200, reveals a Linux operating system and support for Roon, as a RoonReady endpoint, Squeezelite, MPD / DLNA, AirPlay, and HQPlayer as a Network Audio Adapter (NAA). I know many readers will want to understand differences between the sMS-200 and the Sonore microRendu, and the software is where a major difference lies.

The software running on the sMS-200 is less stable and far less advanced than that of the Sonicorbiter OS running on the microRendu and Sonore's Sonicorbiter SE hardware. For example, I frequently switch USB DACs and input applications on these devices. When doing so, the sMS-200 didn't always work. I tried to restart the application such as RoonReady or HQPlayer NAA, but sometimes these apps would just spin in circles, as if stuck in a loop trying to restart. To resolve the issue I restarted the whole sMS-200. Once rebooted, everything worked great.

Another less than advanced "feature" of the sMS-200 is the requirement that each update to the system software be done serially in order. When updating my review unit, I clicked the update button, waited for the update to download and install, then restarted the unit. Upon reconnecting to the web interface, I had to update to the next version and go through the same procedure. Unfortunately I was about five versions behind the current release, so I had to manually update the unit five times. It would be nice to just click update and have the sMS-200 update to the current version of the software (from version 1 to version 3 in a single update rather than from version 1 to version 2 to version 3).

One other piece of the sMS-200 software that could use an improvement to get closer to the level of the microRendu is the informational screens, or lack thereof. The mR offers several places to get information about the connected USB DAC. This would have been nice on the sMS-200 when I had issues connecting to the McIntosh D1100 DAC. It turned out to be an issue with the DAC, but I was unsure because I didn't have any information about the connection from the DAC to the sMS-200, like I did when connecting the same DAC to the microRendu. There are little things that the Sonicorbiter operating system, used by Sonore products, does much better than the sMS-200 OS. Some users will never notice these things and never care about the differences. Others will find that these are deal breakers. I'm just presenting the information so each reader can decide for his or herself.

One area where the sMS-200 has a leg up on the microRendu is when playing high resolution content under a very specific set of conditions. I'm not talking about sound quality here, I'm talking about playback without dropouts. On the rare occasion that someone has an enterprise class network (think Cisco switches and the like), and plays 24/192 content or DSD128 or upsampled HQPlayer material, the microRendu can drop tons of packets. This leads to dropouts because the mR's 1 Gbps Ethernet interface can't keep up with the incoming data. The sMS-200 only has a 10/100 Mbps Ethernet interface and this somehow makes the sending servers slow the data down. Even setting a switch or the microRendu manually to 10/100 doesn't fix the issue for the mR. The mR's gigabit interface is an achilles heel in these very rare circumstances. No, extremely rare circumstances, that I've only experienced in my home. The problem doesn't happen when using Roon because Roon Labs implemented a fix for the issue last year. In addition, I can slow down the data just enough if I stick an Ethernet isolator from Baaske inline with the mR. This resolves the issue 100%.  

Note: I mistakenly thought the sMS-200 had a 10/100 Ethernet interface and that was the reason it worked when the microRendu didn't, but I've been corrected by SOtM. The sMS-200 has a gigabit interface. 

Overall, I think the sMS-200 is a really good product that needs some tweaking on the software side. The hardware is pretty fast and accepts either the SOtM power supplies or any of the aftermarket supplies that the CA community is so fond of using (myself included). By explaining a few of the shortcomings of the sMS-200, I hope to make decisions easier for people considering a product in this category. If these shortcomings don't bother people, they may just save some money by selecting the sMS-200 over a more expensive product.

Listening

I've had the SOtM sMS-200 in my system for a pretty long time. During this time, I've connected the unit to many DACs. Based on my tests, the sMS-200 had no trouble playing PCM or DSD (via DoP) to any of them. Playback of Native DSD may be a different story, but I was unable to test native DSD for this review.

The system I used for much of my listening consisted of a RoonServer outputting to the SOtM sMS-200 to either a Berkeley Audio Design Alpha USB / Alpha Reference DAC Series 2, EMM Labs DA2, dCS Rossini, McIntosh D1100, or Schiit Yggdrasil DAC. The analog side of the system was a Constellation Audio Inspiration PreAmp and monoblocks, with Wire World cabling. Powering the sMS-200, I used the SOtM mBPS-d2s "intelligent battery power supply."

Earlier this week, the McIntosh Group hosted John Mellencamp at its townhouse on Lafayette Street in lower Manhattan. I watched the interview and was inspired to listen to John's new album and his older stuff that got him inducted into the Rock and Roll Hall of Fame. I stumbled upon an acoustic version of Pink Houses (DR11) via Tidal. After listening to the track a few times I created an acoustic playlist and added both the acoustic versions of the Stone Temple Pilots' Plush (DR12) and Pearl Jam's Elderly Woman Behind the Counter in a Small Town (DR11) to the playlist.

One thing was constantly on my mind as I played these three acoustic tracks. The sound is so clean. It's hard to explain more about this sense of cleanliness that I heard. In a way, this is like proving a negative. How do I write about something that isn't present? As I switched from the dCS Rossini to the EMM Labs DA2 to the McIntosh D1100, I could hear clear sonic differences when playing the same acoustic tracks. This is exactly what a source component should enable. I should be enable one to hear the differences between components further downstream, as well as components upstream and most important of all, the recording.

On Pink Houses, I heard nothing but John Mellencamp's voice and his guitar. Ah, that sounds rather stupid, as this is an acoustic recording. But, this was something different. The sound provided a view back into 1983. Perhaps the fact that John's voice sounded 500,000 cigarettes cleaner, contributed to the lack of grunge, noise, or anything I would consider dirty. Note: John estimates that by 2010 he had smoked 650,000 cigarettes in his life. Later in 2014 he told the Associated Press, “Two million cigarettes later and I finally sound like a black guy. Thank God. The cigarettes finally paid off. They’re going to give me cancer and they’re going to kill me, but for a short amount of time, they’re going to make my voice sound like it should.” Given that the acoustic version of Pink Houses was recorded in 1983, John's much-less smoke-affected voice contributed to this very clean sound I heard. I also can't discount the fact that the SOtM sMS-200 doesn't seem to be adding any noise to the recording.

This raises some serious questions, 1) Is the SOtM sMS-200 doing anything to the signal to make the music sound clean? 2) Is this clean sound similar to edge enhancement in video, that soon becomes unnatural and annoying? Without a deeper scientific analysis of the sMS-200, I can say that all the music is bit perfect. The sMS-200 isn't changing anything that would cause my bit perfect indicator lights to go dark on a couple DACs. Also, I haven't experienced any fatigue or unnatural sound when using the sMS-200. This leads me to believe the music signal isn't changing and if something else is at play, it isn't a negative to my ears in my system.

Sonically, this clean sound is very different from the sound I hear through the microRendu. That statement shouldn't be taken to mean the microRendu is the opposite and dirty sounding. Rather, the mR sounds more organic and analog-like than the sMS-200. From a technical point of view I can't explain the sonic differences, but I suspect some of this may be related to the different power supplies and technologies, or there's always the placebo effect. I'm disinclined to believe it's a placebo, based on the amount of sonic difference I heard between the units.

Comparing the sound of the sMS-200 to the microRendu further, I listened to some 1970s rock and roll. I've been on a real 70s kick lately. Playing it for my five year old daughter in the car on the way to school in the morning as well. Not sanctioned by the hoity-toity audiophile society, but damn good music made to sound as good as it can through a real HiFi system.

I put on Fleetwood Mac's Gold Dust Women in 24/96, first through the microRendu. Once I had that sound committed to memory as much as possible, I switched to the sMS-200. I immediately thought the sMS-200 was louder. I don't know what contributed to my perception, but I know it wasn't a change in the audio signal. I was so concerned that I immediately checked the sMS-200 and the microRendu for bit perfect audio (again). Both were sending unaltered audio to the dCS Rossini.

Despite the (mis)perceived difference in volume, I heard the same types of differences with Fleetwood Mac that I heard with the acoustic tracks, but a bit less audible and with a slight twist. The sMS-200 was very clean, just as it was previously. The sonic cleanliness was nice, but it perhaps gave the sound an ever-so-small amount of sterility. By contrast, the microRendu sounded a little lower in level and, as it did before, sounded more organic and closer to an analog sound. Neither device is perfect nor 100% better than the other, for all people in all systems.

I'm unsure if the sonic differences I heard would be present in another system, connected to different equipment. Or, if they'd be present with someone else's ears and brain. When considering a device such as the sMS-200, one should consider the whole, rather than a single piece. Consider the software, support, upgradability, sound quality, and anything else that's important to the individual.

Conclusion

The SOtM sMS-200 is a reasonably priced Ethernet to USB converter that adds Roon, DLNA, AirPlay, Squeezelite, and HQPlayer NAA to almost any system. If the sMS-200 hardware is the system's heart, the operating system is its head. Based on my tests, the sMS-200's heart is in the right place, but its head is a few steps behind the curve. Also note, this may not mean anything to those who want to set it and forget it. The SotM sMS-200 will likely work very well if connected to a USB DAC, set to one of the output modes such as Roon or DLNA, and left alone. In fact, this is what I imagine most users will probably do with the unit.

When it comes to sonic quality and the sMS-200's ability to reproduce music, it's a wonderful piece of equipment. The sound I heard through my system, with the sMS-200 in the mix, was incredibly clean. In a way, it was like a pristine Steely Dan or Donald Fagen recording. Everything was tight, with no loose ends or extraneous frequency bumps. Compared to the microRendu, I'll say the sMS-200 is like a clean crisp compact disc whereas the mR is more like a 180 gram vinyl record. Both can deliver the goods sonically, but one may be better suited to a user's specific taste or requirements.

I'm certainly sold on the concept of the SOtM sMS-200 and all its input application options. I used this device, and its competitors, seven days a week here at CA HQ. The product is very capable of delivering what most HiFi aficionados want, and that's great sound quality first and foremost. I recommend everyone in the market for such a versatile device consider the SOtM sMS-200 and its matching mBPS-d2s power supply. Many people will find they can simply add this SOtM combination to any existing USB DAC and call it a day.

Product Information:

• Product - SOtM sMS-200 ($450 or $510 w/ 1 yr. Roon subscription), SOtM mBPS-d2s ($450)
• Product Page - sMS-200, mBPS-d2s
• Operating Instructions - sMS-200 (PDF), mBPS-d2s (PDF)

Associated Music:

• Computer Audiophile 100 Playlist
• Computer Audiophile PJ4CA Playlist

Associated Equipment:

• Source: Roon
• DAC: Berkeley Audio Design Alpha DAC Reference Series 2, dCS Rossini, McIntosh D1100, EMM Labs DA2, Schiit Audio Yggdrasil
• D-to-D Converter: Sonore microRendu, Sonore Sonicorbiter SE
• Amplifiers: Constellation Audio Mono 1.0 / Monoblock Power Amplifiers
• Preamplifier: Constellation Audio PreAmp 1.0
• Loudspeakers: TAD Labs CR1 Compact Reference
• Remote Control Software: Roon Remote
• Remote Control Hardware: iPad Air 2
• Playback Software: Roon, HQPlayer, JRiver
• Network Attached Storage (NAS): Synology DS1812+, CAPS v4 Cortes Server
• Audio Cables: Wire World Platinum Eclipse 7 Interconnects (XLR & RCA), Wire World Platinum Eclipse 7 Speaker Cables, Wire World Platinum Starlight 7 Digital Cables,
• USB Cables: Wire World Platinum Starlight 7 USB 2.0, AudioQuest Diamond USB 2.0, Nordost Purple Flare USB 2.0
• Power Cables: ALO Audio AC6 Power Cables
• Ethernet Cables: AudioQuest Vodka Ethernet Cables throughout system
• Network: Cisco SG200-26 Switch, Baaske MI-1005 Ethernet Isolator, Apple AirPort Extreme, Calix 716GE-I Optical Network Terminal, ZyXEL C1100Z modem / router, CenturyLink 1 Gbps download / upload