Review: Sonore microRendu
For the past several years, I’ve been listening to all of my digital music via a home built, PC based music server initially running the VortexBox operating system, and more recently, Daphile. My server is a near twin of the original Computer Audiophile “C.A.P.S.” design, with the only real differences boiling down to the aforementioned headless Linux operating systems in place of Windows and JRiver Media Center, and initially a PPA Studio USB output card (now an UpTone Regen) in place of Chris’ recommended SoTM USB card.
The advantages of the CAPS server are many. The upfront cost compared to traditional commercial music servers is very low, you don’t need to spend hundreds on exotic ½” thick aluminum front panels if you don’t want to, and things like the power supply and USB or S/Pdif output are totally up to you. The downsides are largely in the components that you have no control over, like the on-board DC-DC converters which take the squeaky clean incoming DC voltage from your linear power supply and spit out voltages that the CPU, RAM, and harddrive(s) can make use of. Imagine drinking the finest wine through a garden hose. What comes out is never going to taste as good as what went in.
Despite those weaknesses, the truth is that a CAPS style server when powered by a decent linear supply and with a cleaned-up USB output can easily take on most servers and streamers that can cost upwards of $5K or more, which is why I’ve never felt the need to buy one. That all changed however when I heard about a tiny little streamer from Sonore, with the potential to upend this product category like nothing I’ve ever seen before.
Getting To Rendu, Getting To Know All About You
Sonore has been in business for a number of years, and has produced a variety of different products. I first became aware of them in the late aughts if memory serves, when they were producing music servers not hugely different from my own, just built to a higher standard, and in exotic cases from HDPlex and A-tech Fabrication. As the market moved from servers with built in hard drives to Ethernet streamers designed to pull music either from other computers on the network or from NAS boxes, Sonore moved with it, creating the Rendu and Signature Series Rendu. These products featured a single Ethernet input and an S/PDIF output, with an extra HDMI output using PS Audio’s I2S over HDMI spec optional on the Rendu and standard on the Signature version.
The standard Rendu at $1300 was more affordable than most competing models, but still definitely more than the cost of a home built CAPS server, and the $2500 price of the Signature version put it out of reach of a lot of potential customers. Now, Sonore has replaced both models with the new microRendu, at half the price (and well less than half the size) of the original Rendu model, and the rumor mill says that it’s not just better than before, but potentially better than the megabuck stuff as well. A game changer. Imagine a $640 Pro-Ject turntable taking down a $25K Spiral Groove SG-1.1, and you’ll get the idea. I knew I had to get one to see what’s what.
A True Pocket Server
The CAPS acronym stands for “Computer Audiophile Pocket Server,” and the “pocket” part of that was always an exaggeration. Even an Intel NUC case will have a tough time fitting into anyone’s pockets, unless you happen to be wearing JNCOs, which are a thing again, apparently. With the microRendu though, the word “micro” is apt. This thing is smaller than an old Palm Pilot or Blackberry.
So how’d they do it? Well the microRendu was a collaborative effort. Sonore’s Jesus Rodriguez and Andrew Gillis of Small Green Computer (the creators of VortexBox) have years of experience working together to improve Linux audio playback, and they put together the software necessary for the microRendu to function. The hardware side came from John Swenson of JS Electronics, creators of the Uptone Regen. If you’ve seen the Regen before, John’s influence on the design of the microRendu is more than a little obvious. The two products basically look like twins separated at birth. There’s a lot more going on inside the Rendu though, which makes its tiny size all the more impressive.
Next to the USB output on the front of the microRendu is an SD card slot. Unlike some other servers and streamers which can read music stored on a memory card, this slot is actually used for the operating system. This gives them two main advantages over an embedded flash ROM chip: first, the SD card creates much less electrical noise when data is accessed by the main system processor than an embedded chip would, and second, if there’s ever a problem with the software, the SD card can be swapped out in the field, no need to send the unit back to the factory. Trust me, these guys have left no stone unturned.
Fire It Up
Getting started with the microRendu is about as easy as it gets for this type of device. Plug your network cable into one end, and your USB DAC into the other. Connect a suitable power supply (more on that later), and go. Initial setup is handled via a web interface much like VortexBox and Daphile, and once that’s done, you’ll have full control of music playback with any smartphone or tablet. I checked with Sonore about using an 802.11ac wireless Ethernet media bridge for those that may not have wired Ethernet available in their listening area, and they responded that it may work great, or it may not. Since Wi-Fi performance is very dependent on a number of factors from range to room layout to even building materials, it’s impossible for them to make any guarantees that a Wi-Fi connection will work perfectly.
The software initially takes you to a page showing any currently active music servers on your network, and the microRendu’s software, local IP address, and MAC address, making it very easy for you to add it to your router’s DHCP reservation list. I personally have no love for either HQPlayer or MPD, (or the desire to pay for Roon), but fortunately Logitech Media Server is also supported, and with Squeezer already on my phone, I was able to have music playing in a matter of seconds.
I began my tests with “The Rhymes of the Mountain” from Borknagar’s latest, Winter Thrice. The production on this track is typical Borknagar – dense and loud, with the swirling synths, guitars, harsh and clean vocals, and drums (what there is of them) all competing for very limited space. The microRendu really brought out absolutely every last detail from this track. It’s no miracle worker; it can’t turn Jens Bogren’s DR6 production (Boooggreeeennnn!!!!!!!) into DR12 Swanö magic, but listening further into the album, Borknagar sounded better than I can ever remember hearing them in my system before, and to no small degree.
From there, I moved on to “No Lonelier Star,” from Draconian’s Sovran, their long awaited follow up to 2011’s A Rose For The Apocalypse. This album has a fair bit more dynamic headroom than Winter Thrice, and it really allowed the microRendu to strut its stuff. Kick drum hits landed with concussive force, and Heike Langhans seemed alive in the room; her soft tones floating ethereally above the rolling thunder of guitars.
For a change of pace, I decided to head back in time a few decades, and fired up “Chosen Ones” from my needle drop of the original pressing of Megadeth’s Killing Is My Business. Oh yeah. Oh, this is good. I’ve already known since I picked up this old pressing how exceptional it sounds since I’ve played it live on my SOTA Sapphire. The microRendu streamed my 24/192 needle drop over my network without missing a beat, and was every bit as enjoyable to listen to as spinning the record itself. It’s hard to say if it matched the Sapphire exactly – with a fully manual arm you can’t exactly cue up tracks at a moment’s notice for quick and easy A/B testing, but the two were at least damn close. For some perspective, my Graham Slee phono preamp costs twice as much as the microRendu does. Just the preamp.
As I went through album after album, every time I swapped my Daphile server back in, I was keenly aware that things weren’t quite as good as before. Kick drum hits were less distinct, there was less shimmer from the highs, and the overall sonic image seemed to shrink a bit. The severity of the changes depended on the album. The better the recording, the further the microRendu took the lead. And keep in mind that my server is no slouch. The main source of DC comes from a superlative TeddyPardo linear power supply. There are no wireless or Bluetooth antennas, no keyboards, mice, or other USB connected devices to introduce extraneous noise, and there are no moving parts – the ultra low voltage processor uses a simple heatsink. The only connected device is my Uptone Regen, which sends a re-clocked data stream and a fresh source of 5V DC to my Lindemann DAC. Despite all of that, it’s tiny size, and it’s very affordable price tag, the microRendu still came out ahead. Did I mention this thing is a game changer?
Very late in the review period, the DC iPurifier and the new second generation USB iPurifier arrived from iFi Audio (stay tuned for a separate review on those). This was very fortuitous, as it allowed me to do some final testing with my server taken about as far as it can go while keeping the price anywhere near that of the microRendu. I could spend thousands on ultra exotic power supplies, but that would miss the point. Not to mention the fact that, even with a power supply ten times the cost of the TeddyPardo, that DC must work its way through the power converters on a low cost, off the shelf Asrock mini-ITX motherboard. With the USB iPurifier giving the data stream a second round of scrubbing, and the DC iPurifier cleaning up the Regen’s stock switch mode power brick, my server clawed back some, but not all of the difference between it and the microRendu. The rumbling bass on “Sanction” from my needle drop of Katatonia’s The Fall Of Hearts was definitely more evident with my server taken to the nth degree, but the Sonore still did it better.
There’s also one last wrinkle. The microRendu requires 6-9V of DC to function. Since I didn’t have a suitable power supply in that voltage range on hand, Sonore sent along an iFi Audio 9V wall-wart for the review. It’s very good as far as wall-warts go, but it’s still a wall-wart at the end of the day. I have no doubt that with its own TeddyPardo, or Sonore’s linear power supply, or the brilliant Paul Hynes Audio SR3 which I highly recommend that Sonore add to their list of suitable candidates, the microRendu has even more sonic improvements waiting in the wings.
If you have a great engineering team and an unlimited budget, you can make a state of the art music server or streamer. Aurender did the former with the $17,600 W20 server, and Naim did the latter with the NDS and 555PS power supply (originally £12,620, now, who knows). While both are unquestionably impressive, they are also only relevant to hedge fund managers. Building a streamer that is even within the same universe as these hyper-dollar flagships with a retail price of $640 would seem a near impossible task, and yet the team behind the microRendu have managed far more than that. As I said at the beginning of this review, my Daphile server without the iPurifier combo in place is very competitive with servers and streamers up to the $5K mark and beyond, and the microRendu beat my server pretty handily.
The microRendu brings Ferrari sound quality at a Ford price; I really don’t know how to make it simpler than that. Medal of honor winner? You’d better believe it.