Your Final System (YFS)

HD Ref 3 Music Server

$13,000 as tested

Review by

Dr. John Richardson


One of the most rewarding aspects of visiting audio shows such as the Rocky Mountain Audio Fest is that I get to learn about new companies just coming on the scene, proudly demonstrating their newest creations.  Sure, everyone goes to hear the high profile rooms that are touted by the big name magazines.  You know, the Magicos and Wilsons of the world.  I’m certainly not knocking Magico, Wilson, or any of their big hitting megadollar compatriots here, but my primary joy comes from visiting those rooms that are just off the beaten path, tucked out of the way in the nooks and crannies where no one else thinks to look.  I see an interesting new company’s name on the door, I just know I need to wander in.


Such was the case with the Your Final System (aka YFS) room.  Upon entering I found myself drawn in immediately, as there was a lovely system playing around a big black box on an audio rack, as well as what appeared to be several home-crafted separates, including a lovely looking preamplifier.  Here also I met the chief proprietor of this operation, a fellow by the name of Kevin O’Brien, along with his father, Michael.  Michael was the first to notice me sitting there, and we immediately struck up a conversation.  As it turns out, Michael designs analog circuits for aerospace applications, where size, durability, and functional reliability not only count, but could mean the difference between life and death for the project at hand.  Ever wonder what happens when a circuit fails on a man-made satellite or spacecraft?  I figure the result can’t be good (just ask the guys on the Apollo 13 mission...).  Michael explained to me later that he designs all of his analog audio circuits just like he would if he were to send them into space:  overbuilt, short signal paths, and with as efficient use of components as possible.  Use the best component for the job and leave it at that; don’t muck up the elegance of the design.  Take commercial audio power supplies as an example.  Michael related to me how most audio manufacturers build power supplies according to older protocols that no one in any other high-precision industry still uses.  Not only can he make them simpler, he claims, he can make them more reliable and better sounding.


Like his dad, Kevin O’Brien is also a mechanical engineer.  Unlike Michael, however, Kevin specializes in the digital side of the game.  For our purposes, that means he designs and builds highly sophisticated state-of-the-art music servers.  Building on the hard work of himself, Michael, and several other engineers, Kevin recently decided to re-locate the server arm of YFS from Rochester, New York to Boulder, Colorado.  Lucky guy...I’m told the skiing out there is pretty fantastic.


The subject of this review is YFS’s all-out assault on the state-of-the-art music server, a device called the HD Ref-3.  For the less technically inclined among us, it might be helpful here to review exactly what a music server is and what it does.

As most of you are aware, most music purchased and enjoyed today is of the digital variety.  You can buy it pre-packaged as a cd or dvd, or you can download it electronically from a vendor such as Apple’s iTunes store, Amazon, or HDTracks.  Ask any teenager (or pre-teen, for that matter) and they’ll be glad to explain it to you.  Once we have our digital file (let’s say it was downloaded), how do we access and play it?  Well, you could use an iPod or some other portable digital storage/playback device.  As it turns out, the iPod itself is really just a miniature music server.  As such, it does several things: it stores your music on a miniature hard drive, allows you to access and arrange your tunes in playlists, and lastly, lets you play them back.  In essence, these are the three primary jobs of any music server!


For the more discriminating audiophile, the iPod and its relatives have proved to be sonically insufficient for a number of good reasons.  In the early days of computer audio, therefore, most of us had to put together our own versions of music servers, typically built around commercially available desktop computers of both the PC and Apple varieties.  For example, the Mac Mini was, and continues to be, very popular for this application.  Of course, typical audioholics would also want to get all of their digital files, some of which might be high resolution, onto the device.  This challenge was overcome by employing a high capacity external hard drive.  Finally, we needed software to help arrange and organize our music into accessible playlists, offer a playback interface, and even display album art.  Again, this challenge was initially met by programs such as iTunes since folks were downloading music to their home computers and then dumping it onto their iPods (it’s called syncing the devices).  Unfortunately, two problems still remained.  First, people who cared about sound quality quickly figured out that such programs were not always “bit perfect”, meaning that the digital data were massaged in such a way that what was on the hard drive wasn’t exactly what was getting to the DAC (that’s the digital to analog converter).  Second, the internal DACs on devices such as iPods weren’t of the best quality.  What we needed was a way to get unmolested bits from the storage device to an external DAC for highest sound quality!  The results were a plethora of third party playback programs (Amarra, Pure Music, JRiver Media, and Foobar are just a few that immediately come to mind), and a host of high quality external DACs that could easily communicate with a computer via USB or Firewire interfaces.


Wouldn’t it be nice to wrap all of these components, minus the DAC, into a single box that utilizes a super friendly bit-transparent user interface?  Well, that’s what the modern music server does, but in a highly specialized and linear manner.  One problem with stock computers is that they are not designed with audio applications in mind; they are meant to multitask and grind data.  Very little care is taken to reduce digital and other electronic noise (think jitter) or to carefully regulate power supplies.  As any audio nut knows, these things can contribute to - you guessed it - bad sound.


Enter the good guys at YFS, here to save the day.  Their approach was to build a computer from the ground up whose sole purpose is to handle digital audio files while doing the least possible damage to the music itself.  The result is the HD Ref-3 server, the capstone result of a series of three servers developed over the last year or so.  I won’t dwell on the genesis and evolution of this family of servers, as that’s well documented over at the YFS website (  What I will do is focus on the technological and user features of this present top-of-the-line offering.


I’ll start by emphasizing that every job is considered a custom project, tailored to the specific needs/desires of the customer.  If you want a particular feature or component, just ask.  Kevin will do his best to accommodate you.  If you don’t want to pay for certain modules that you won’t use, that’s ok too.  This is computer server a la carte, so your price will vary accordingly.  Keep in mind that my sample is the fully decked out “Cadillac” that goes for right around $13,000.  More money can get you more digital storage space, higher processing power, greater noise suppression, and the like.


Let’s start with the chassis itself, which is oversized, well ventilated, and crafted of carefully finished and painted heavy steel.  This isn’t your typical desktop PC box.  On the front is a lockable fold down panel that exposes the local power switch and reset button, as well as the CD/DVD drawer.  Dead center is a LED that indicates proper and normal operation when burning blue.  I also found it quite easy to pop the top panel for easy access and viewing of the interior components.  I’d guess that such an enclosure serves as an effective Faraday cage, keeping spurious external RF grunge out, as well as something of a heat sink for internal components given the amount of excess surface area present.


What really matters though is what’s packed inside:  the processor, RAM, data storage modules, interface cards, and the like.  All of these components have to work together as a well oiled machine to give us the best sound possible with the least interference.  Even the arrangement of the modules inside the case makes a difference, so a great deal of research and development, as well as tinkering based on critical listening go into optimization of the design of a server such as this.  Oh, and the server’s contribution to the ambient room noise must be kept to a minimum as well, since the gadget will most likely be sited near the end user’s listening position.


Let’s now get small, duck into the chassis, and have a look at a few technical specifics of the HD Ref-3 server.  Offered as standard fare are six-core processing, 32 GB of RAM, a 512 GB solid state hard drive, and a SOtM USB PCI interface card (this offers a high-tech means of communication with your USB DAC, for example), complete with its own external linear power supply.  The option also exists to go with a RAID storage system with up to 1 TB of solid state memory for those really large music collections (this will cost you, however...).  A quick look inside the box indicated a well-thought-out layout with plenty of space for these individual components to breathe.  Speaking of breathing, I was surprised at how quiet this server was.  It does employ a cooling fan, but if it ever came on, I never heard it.  Granted, I positioned the HD Ref-3 away from my listening position, but it remained absolutely silent every time I approached it.  YFS claims it to be probably the quietest music server in existence, and I’d believe it; even my reasonably quiet Mac Mini doesn’t hold a candle to it when its fan gets going, and I won’t even bring up hard drive chatter.


When it comes to describing the sonic impressions of a music server during playback, I find the task at hand a bit difficult to address.  A server is just a computer handling the release and delivery of musical digital bits to your DAC, for heaven’s sake.  However, anyone who’s meddled in computer audio will quickly tell you that everything matters when it comes to sound quality.  I’ve definitely found this to be true in my own experience as well, whether messing with production servers or my own concoctions.  Truth be told, the music server has to be treated just like any other audio component; in some sense, it’s really not all that different from the digital audio transports of yesteryear, back when compact disc was king.  They made a difference in the quality of audio reproduction, right?


OK, then, what did the HD Ref-3 sound like? 


After many hours of listening through the YFS server, I’ve come away very impressed with its sure footedness and the absolute silence between the notes that it offers.  Often when we read about analog gear such as amplifiers and turntables, or even components like DACs which still have an analog section, we refer to the component’s ability to “get out of the way” of the music by not editorializing it in any way.  Of course, this is a tall order to ask of any analog components, since by their very nature they add their own sonic signature to the musical waveform to some extent; there’s just no real way around the problem.  In contrast, the requirement of sonic purity should be easier to achieve, at least in theory, with a music server, as the music is never handled in the analog domain:  it’s the old “bits is bits” argument.  But remember, in computer audio, everything matters...


Fortunately for me, the guys at YFS sent the server to me loaded with lots of great music.  Some was standard Redbook stuff, but much was of higher resolution (the server will handle files of 16, 24, and 32 bits with resolutions of up to 384 kHz).  Some of the music I was familiar with, much of it I wasn’t.  No worries, though, as I love to explore new musical offerings.


Operation of the server was achieved in two possible ways:  using a hand-held tablet, or by accessing a larger, stationary, touch screen monitor.  Kevin O’Brien initially set me up using the tablet, but after a few days, the server for some reason refused to communicate with the tablet through the wireless router we had set up specifically for the job.  After a few subsequent false starts with the tablet, I decided to give the touch screen monitor a go.  This approach, fortunately, worked flawlessly.  My only complaint is that the monitor had to remain hard wired to the server, so it lived between the speakers, perched atop the server itself.  I had to get up and walk over to it any time I wanted to change the music selection.  Even so, the process was still a lot easier than changing out a CD in a traditional player.  My, we have become spoiled by technology, haven’t we?


The system utilized with the YFS HD Ref-3 was my usual.  On the digital side was my Antelope Audio Zodiac DAC, fed through its coaxial SP/DIF input bits via a M2TECH HiFace EVO usb to SP/DIF converter supplied by Kevin.  As an aside, YFS can customize the usb output from the SOtM usb interface card to any usb DAC out there; the EVO just lets it work with any DAC, so that’s what we settled on.  Amplification was provided by a REDGUM RGi60 ENR integrated amp powering Shahinian Compass speakers.  I also used my Shahinian Double Eagle subwoofer, powered by an ODL HT-2 amplifer for some of the evaluation.  All components were plugged into my Spiritual Audio VX-9 line conditioner.


The bottom line is that I really love listening to music through the HD Ref-3.  It seemed to truly bring out the best in my system, allowing the other components to sing as they should.  Grunge?  Fugeddaboudit!  Stridency?  None to be heard here... Move along now.  This thing just sounds correct to my ears; digital done right.  Master tape clarity with scads of darkness between the notes.  Need I go on?  Then again, the cheap bastard part of me says that for 13,000 clams, the gadget should sound awfully good.


As much as I was enjoying the music provided by Kevin, I knew I needed to put some of my own tunes on the solid state drive and see how they compared to playback via my own homemade Mac Mini server.  There’s a tutorial over at the YFS website that describes how to do this with the Album Player playback/organizational interface that Kevin prefers.  I followed this protocol and managed somehow to get some of my high resolution wave files over to the server.  File management was a bit funky, and I suspect  the whole process would be easier using commercial disks or downloads.


Several of the files I copied over were cuts from an album I was lucky enough to recently acquire on vinyl:  Shelly Manne’s 234 on Impulse!  My copy is a near mint early orange and black label stereo pressing mastered by Rudy Van Gelder.  The sound is breathtaking in its immediacy and punch, especially from Shelly’s drum kit.  Even my 24/96 digital transcription sounded amazingly good, capturing most of the presence of the original vinyl.


OK, I’ve really enjoyed listening to 234 with my Mac-based server, but the YFS server took the experience to a whole new level.  I now have a new appreciation for my vinyl transcriptions, as the result was cleaner, clearer, punchier, and less veiled.  Shelly Manne’s drum kit was right there with me, and I could easily hear the slight sense of decay and reverberation as the individual hits reflected off the surrounding walls.  I could hear this through my normal server as well, but all of the detail and timing was that much more defined and accentuated with the HD Ref-3.  I’m wondering how much of this improvement has to do with the solid state storage device, as I also noticed such improvements when I reviewed the Pacific Valve Cyberserver awhile back; this device also sported a solid state hard drive.


Even with all of the improvement in timing, detail, and transparency, I felt that there was no loss in those other all-important factors to musical enjoyment:  timbre and tone.  Both instruments and voices sounded just right, full and layered harmonically, with no sense of being threadbare or strident.  Neither were they fat or overdone, unless that was how they were portrayed on the original recording.


Furthermore, one does not require super accurate and expensive modern speakers to thoroughly enjoy the HD Ref-3.  At the end of my review time, I decided to have some fun.  On a lark, I recently picked up a nice set of vintage JBL 4311B control monitors (don’t laugh... I know this amounts to no less than audiophile suicide, but I think we can agree to find lots of ways to enjoy the hobby).  Yes, I know these speakers are flawed, as are most vintage transducers, but hey, they make rock ‘n’ roll and jazz fusion tunes sound exciting, just like they did when I was a teenager!  High frequency hearing loss, anyone?  Even so, all kinds of music sounded delicious through the HD Ref-3 via the JBLs, which I set up in a near field configuration right by my listening seat.  I could even still hear quite distinct differences between my Mac server and the HD Ref-3, even at very low volumes, which is how I listen at night after the Mrs. has gone to bed.


In some ways, I’d even go so far as to say that the JBL speakers let me hear the differences between my own server and the YFS unit more clearly than my beloved Shahinians.  Perhaps this has to do with their design and intended use as studio control monitors, as well as their setup in a near field configuration, thus taking the room out of the equation.  With the HD Ref-3 in the chain, music via the JBLs sounded more together across the audible frequency range, with maybe just a touch of tizziness in the treble at my normal low volume listening levels.  Without the Ref-3, my tunes tended to sound boomier and less controlled in the bass, with certain bands in the midrange standing out, along with a more aggressive treble.  In short, the HD Ref-3 seemed to do a better job of controlling the JBL beasts and making the music seem more reined in and accessible over the long haul.  Of course, normal logic would spit in the face of mating a $13,000 music server with such a pair of vintage speakers in the first place!


Either way, the bottom line is that the YFS Ref-3 server made all of my gear sound better, yet again suggesting that an excellent source component will improve matters all the way to the speakers, provided there aren’t big problems elsewhere in the system.  In short, the Ref-3 did a superb job of making music and engaging me heartily in its enjoyment.


So then, what’s the final word on value, especially from a value minded individual such as myself?  On one hand, I think it’s ludicrous to spend $13,000 or more on something that is really just a computer tweaked to do audio.  If you look around, there are other excellent servers to be had at $3000 and below, but of a definitely more homemade and less flexible variety.  For the right buyer, however, what the Ref-3 offers that the others don’t is nearly infinite customization.  Each is a unique, one-off design using the best quality parts available based around a central processor; anything beyond this is totally up to the customer.  If you want that level of customization and support, you need to be willing to pay for it, as you’re buying many, many hours of design and build time from a team of highly skilled engineers.  Keep in mind also that you’ll want to work in potential upgrades as technology changes in the processing and data storage worlds.  Further, as I have noted before, solid state memory makes a big audible improvement, but it’s still relatively expensive.  The Ref-3 I have came with only 512 GB of solid state storage.  A typical archived digital transcription of an LP that I make at 24 bit/96 kHz resolution takes up around 1.5 GB.  You can do the math and see that you won’t fit 2000 uncompressed high resolution downloads or albums on that drive.  Oh, and don’t forget you’ll need a DAC whose quality is commensurate with the server you just designed, configured, and bought.


Bottom line:  if you have the cash and are looking for a totally customizable turnkey music server built to the highest standards possible today, then the YFS HD Ref-3 should be on your short list.  Give Kevin O’Brien a call and see what wonders may lie before you.



Some folks want the absolute best and are willing to pay for it.  Others just want lots of options and flexibility.  If your audio desires fall into either of these categories, then the YFS HD Ref-3 music server might just be your cup of tea.  It’s immaculately engineered and built, and its mere presence in one’s system is a statement in and of itself, both visually and sonically.  This server will handle just about any digital audio file and can be  custom configured to play nicely with your favorite DAC.


On the downside (there’s always a downside, right?), it’s very expensive, and the cost will only increase as more digital storage space or processing power are added.  Also, the potential owner needs to worry about modules becoming obsolete.  If I were in the market for the HD Ref-3, I’d talk to the folks at YFS about the potential cost of upgrading to keep the system cutting edge.  After all, if you are seriously considering spending northwards of $13,000, you really do want this to be part of “your final system.”


Finally, if you do take the plunge, I can assure you that you will get exemplary service and support from the O’Briens and their colleagues.  For example, for a reasonable fee, they’ll even travel to your home to set the server up, help you get your files transferred, and optimize the device to your liking.


Outside of the trouble I had interfacing with the tablet, I found the HD Ref-3 to be absolutely bullet proof.  It never heated up and remained quieter than a mouse, never missing a beat over the couple of months it lived with me.  Oh, and it really did take my system to a new sonic level!



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