Reviewer: Glen Wagenknecht
Financial interests: click here
Sources: Audio Space CDP 8A CD Player
Wyred 4 Sound Music Server
DACs: Wyred 4 Sound DAC-2, Grant Fidelity Tube DAC 11
Preamplifier: Audio Space Reference 2S, Tortuga Audio LDR6 Passive
Amplifier:Bel Canto 200.4 Tapping TP22
AV Receiver: Pioneer Elite SC-25
Main Speakers: Apogee Duetta Signature, Paradigm Servo 15 subwoofer
Audio Space AS-3/5A
Rack: Codia Acoustic Design Stage 1000
Stands: Charisma Audio Function Stands   Target Stands
AV Speakers: JohnBlue M3s
AV Subwoofer: Paradigm PW-2200
Desktop Audio Speakers: Swans M200 MkIII
Desktop DAC/Pre Headphone Amp: DA&T U-2
Cables: Arkana Physical Research Loom, Audio Art SE and Classic cable looms, JPS Labs Ultraconductor 2 speaker cables, Madison Audio Lab E3 Extreme 1 Interconnects/Extreme 2 speaker cables, Signal Cable Silver Reference interconnects and speaker cables, digital optical and coax cable, Audio Sensibility Impact SE balanced interconnects and USB digital cables, DH Lab Power Plus AC cable.
Resonance Control: Solid Tech, EquaRack Footers, Weizhi Precision Gold Glory footers, Boston Audio TuneBlock2 footers, Audio Exklusiv Silent Plugs, Audio Exklusiv d.C.d. Base and d.C.d. Footers, Superspikes, CA Electronics Standard Cones, Feet, Cable Clamps, Isoacoustics L8R130, Aperta and L8R200 SUB speaker stands
Powerline conditioning: Exact Power EP15A, Noise Destroyer power filtration
Accessories: TrueHarmonix Black Magic CD Mat, Herbie's Super Black Hole CD Mat
Main Room size: 12' x 17'
Home Theatre: 10.5' x 16.5'
Review Component Retail: $250 (shipping included)

Can a li'l product like the Norwegian Henry Audio USB DAC 128MkII make big waves? At first glance you may think not. It's tiny, measuring a mere 4.5" W x 4.75" D x 1.5" H and weighing in at a paltry 10.6 ounces. Digital input is restricted to mini USB. There is no power cord or power input. Whilst the Henry Audio looks respectably finished, it is certainly a little lightweight by high-priced audiophile standards. Where's battleship aluminium? Where's hefty gold-plated bling? In the audio world, fancy frontage is no guarantee of sonic superiority. Underneath that humble exterior lies some fresh digital to analog magic. This tiny flea weight might just be a serious contender. Henry is an intriguing collaborative effort originating in the fertile minds of Børge Strand-Bergesen and the DIY community as an (ongoing) open-source undertaking called the Audio Widget Project. It takes full advantage of the combined knowledge and skills of a worldwide group of talented enthusiasts. Børge took the fruits of that effort to market a finished product in 2012 under the tongue-in-cheek company name QNKTK (Quantization Noise Killed the Cat), which has since morphed into Henry Audio to appease those less humorously gifted. The company sell internet direct from their website, are located in Norway and have this product built to specification in the Philippines. The original design underwent several iterations, marking progressive revisions and improvements to current 128MkII status. I asked Mr. Strand-Bergesen the basic question.


How did you arrive at this point?
 "Many years ago I started working on some to my mind very nifty signal conditioning for DACs. I built this into an ambitious DIY hi-end CD player. Everything was fine until some 6 years ago people started suggesting USB support. USB audio parts at the time were either highly experimental or not geared towards hifi. Then I discovered the SDR Widget project and asked how they would feel about converting their work into a pure USB DAC. The response was positive and I started making the necessary custom hardware. I have many years of experience in the design and manufacture of circuit boards so it was obvious that this task would fall on me.  I made it modular so analog hackers could take a USB/I²S module and plug it into their analog boards. And I gave it a decent analog board so that digital hackers didn't have to build their own to write code. So I did come to a set table and started moving things around with some very good help from fellow developers. I found a few firmware bugs and contributed fixes to the project. At the same time the ASIO driver came so that UAC2 could be used on Windows. There too I came to a set table and fixed a few bugs. When the firmware was stable, the development effort died down a little and I started working more and more commercially. The DAC received a great review in the Norwegian magazine Watt and the ball started rolling. I've always had a commercial mind. I have learned a lot from the marketing effort for the DAC and still have lots to learn."


In your first iterations of the DAC, you employed an ESS Sabre chip. The new DAC has gone with a different chip. Why?
"ESS don't make their products available through typical electronic parts distributors. Getting them in low volumes was a big hassle. But what made me choose another chip was the discovery of an internal math bug in the ES9022/9023. A >-1.3dB full-scale square wave played through their chip will generate great amounts of distortion. With modern compressed music, that isn't just a theoretical occurrence. I worked many years with signal conditioning and was able to see what goes on. In technical terms, the internal FIR filter does a 2's complement overflow where a very positive number actually flips around and becomes a very negative number. This occurs before the sigma-delta modulator. A digital limiter or lower gain in the FIR would solve this."

The choice to go USB only presents some challenges for high-resolution capability. For instance, USB in Windows seems to only support USB Audio Class 1. Is this why you had to develop your own driver for Class 2?
“You are talking about the elephant in the china shop, the lack of support for USB Audio Class 2 in Windows. With it, hi-res DACs would become plug'n'play and DAC makers won't have to pay crazy money for drivers. And I strongly believe, streaming providers would start offering bigger and better services. The open-source ASIO driver of the Audio Widget project enables hi-res audio playback from select Windows programs via UAC2 with my DAC. To do that, a virtual audio device is installed. Windows recognizes it but there is no associated hardware. Instead, the virtual audio device picks up the audio and sends it to the selected ASIO driver. The overwhelming benefit is that since it is not available to Windows in general, there is no sample rate conversion, no "pling, you got mail". As a curiosity, the ASIO driver is only invoked when music is played back. In foobar2000, you see a list of installed ASIO drivers, not plugged-in ASIO devices."


Just how difficult would it be to create a Windows-based UAC2 driver?
"I tried multiple times to start an open-source effort for a Windows UAC2 driver. The amount of work involved and the copyright of Microsoft's code make this impossible. The whole DAC industry is begging Microsoft to make the drivers but nothing seems to happen. The streaming industry hasn't yet discovered this hurdle. This driver business is complex. If Microsoft decided to become an OS for hi-res audio playback, the world would look rather different for people with a passion or interest for music."


Do Mac and Linux offer better support for UAC2?
"On Mac and Linux, there are built-in drivers for UAC2. However, without intervention, both will still mix sources and convert audio to the highest sample rate reported by the DAC. On Mac, I believe Audirvana fixes this. It can also be fixed on Linux. So you see, the operating systems aren't set up in a particularly audiophile way."


Here's a question on a lighter note. Let's talk packaging. Your company has adopted the Internet direct sales model. My review sample arrived in bubble wrap inside a padded envelope. Would your DAC normally ship with a standard box container?
"I put my efforts into the audio not unboxing experience. For the time being, it comes in a pink bubble wrap bag in a padded envelope. Adding cardboard is easy and would increase the price by $10 or so. I've thought about it but designing new electronics is more exciting."


This marked the end of our e-mail chats. Børge indicated that the DAC will work well on all modern computers with a minimal processor requirement of at least a Core 2-duo/2GHz CPU. Additionally, USB Audio Class 2 drivers may not work on Windows XP. Unlike most DACs, power is derived from and optimized for the DC supplied through the USB cable and does not deal with the issues of AC/DC conversion. Internal supply capacitance exceeds basic chip manufacturer recommendations by wide margins and utilizes an array of smaller caps rather than fewer large caps to ensure that the power supply be extremely responsive.