In March 2011, I reviewed Audio Research’s DAC8 DAC on SoundStage! Hi-Fi, which used a now-ubiquitous asynchronous USB 2.0 input to play files of sampling rates higher than 96kHz. For a conservative company like ARC, that feature was somewhat innovative, it having only recently emerged as the sonically preferable way to play recordings at what was then the highest resolution available: 24-bit/192kHz. That was before files with such exotic initials as DSD, DXD, and MQA appeared. The DAC9 is ARC’s first standalone, popular-level DAC since 2010 -- in DAC years, an eternity -- and, like most DACs, it doesn’t include the latest development in digital audio playback: the ability to decode Master Quality Authenticated (MQA) files. It can, however, play DSD files; previously, the only ARC component that could do that was the GSi75 integrated amplifier.

Audio Research DAC9


The DAC9 is part of ARC’s Foundation line, along with the LS28 line stage, PH9 phono preamp, and VT80 amplifier. Except for the VT80 ($8000 USD), each Foundation model costs $7500 -- they are very nearly the least expensive models ARC makes. Along with the price, the DAC9, LS28, and PH9 also share a similar appearance. Available in Black or Natural (ARC’s term for silver), the DAC9 borrows stylistic features from previous ARC gear -- rack handles, a styling groove around the edge of the front panel, and a digital display with green alphanumeric characters -- and adds some new ones, including a panel of black glass at the center of the faceplate, surrounding the display. The black glass looks even better than it does on the gear made by ARC’s stablemate, McIntosh Laboratory. (Both marques are now part of the McIntosh Group, which also owns Pryma, Sonus Faber, Sumiko, and Wadia.) The small characters of the DAC9’s display barely passed the Squint Test; they were difficult though not impossible to read from my listening position, about 10’ away. (Tip: I keep a small monocular on my coffee table for those components that don’t pass the Squint Test.) The information displayed is useful and complete: no proprietary abbreviations used.

Below the display is a row of six pushbuttons: Power, Menu, Option, Enter, Input, and Mute. The ARC logo, previously stamped on the front panel, is now printed on the black glass. The Foundations look like smaller versions of ARC’s Reference models, and that’s a compliment -- they and ARC’s upscale Galileo series were all designed by the same team. The all-aluminum DAC9 measures 19”W by 6.5”H by 13.7”D and weighs 13.9 pounds.

Audio Research DAC9

The DAC9 has one feature the DAC7 and DAC8 didn’t: tubes in its output section. They’re 6H30Ps, the same tube type now used in the low-level circuits of nearly all ARC models. Fortunately, the 6H30P is still in production in Russia, so replacements are available from most tube stores; however, I recommend buying replacements from ARC, which rigorously tests the tubes before selling them for use in their products. The 6H30Ps are expected to last about 4000 hours; a tube-life timer built into the DAC9 tells you how many hours of playing time your tubes have accrued. The warranty for all ARC gear is three years, parts and labor, and 90 days for the tubes -- typical for a tubed component at this price.

The DAC9 uses the Burr-Brown/Texas Instruments PCM1792A chip. When I opened the case to install the tubes, I saw that the parts quality is first-rate -- in particular, the solid-state power supply is substantial. I’ve owned several ARC components and have never had any problem with them -- they’re built like brick outhouses.

Audio Research DAC9

ARC goes to a lot of effort to provide power cords that sound good, and expects reviewers of their gear to use the stock cords. I use aftermarket power cords, footers, and tubes in my reference gear, but not for the product I’m reviewing -- unless its stock cord looks like a throwaway.

Included in the DAC9’s shipping carton are the remote control, the power cord, ferrite clamps to wrap around the cord if it picks up noise, and an envelope containing extra screws for the top plate. There’s no CD-ROM with a Windows driver, which you’re advised to download from ARC’s website. A good plan -- that way, you always get the latest driver. However, those who lack good Internet access might benefit from a CD or USB flash drive containing a driver. In that case, the dealer should provide a copy.

The DAC9’s chunky metal remote-control handset provides all the controls found on the front panel, as well as some on the menu. The lid to the battery bay is secured by a screw -- a welcome improvement over ARC’s plastic remotes of yesteryear, which had snap-on latches. The DAC9 has no volume control, so you can’t use it to drive a power amp directly. Decent volume controls aren’t cheap; its omission here has no doubt kept the DAC9’s price down. And, of course, ARC makes some fine line stages -- such as the matching LS28, which looks really good next to the DAC9.

Setup and use

As always (ha!), my first step was to read the DAC9’s manual -- easy to do, as Audio Research has printed it in a refreshingly large font, possibly in recognition of the advancing age of the typical audiophile (like me). The manual is easy to understand, and includes color illustrations of computer screen shots and the DAC9’s menu tree. Unfortunately, the text in the color illustrations is dark green type on black, and a bit hard to read. It’s easier to read in the pdf version of the manual, available from ARC’s website.

The two 6H30P tubes, which are shipped embedded in a big block of foam, are marked to show which sockets they are to be inserted in, and their rubber vibration-damping rings are already installed. Using the excellent Xcelite Phillips screwdriver ARC provides, I removed the DAC9’s top plate to install the tubes.

Audio Research DAC9

I’d planned to use my SOtM streaming network music player as the source, but it didn’t work. I then tried another Linux-based player, Sonore’s microRendu. That didn’t work either. Apparently, the DAC9 isn’t compatible with Linux, and that’s a drawback -- dedicated servers/streamers/players are becoming very common, and most of them are based on the Linux operating system. I evaluate lots of DACs -- as I write this, I have five in the house -- and the DAC9 is the only one I can think of that’s incompatible with Linux-based servers.

I switched to my Toshiba Satellite laptop computer as the music player, with JRiver Media Center 22 music-player software running under Windows 10. The third time’s the charm, I suppose; anyway, it worked. An Audience Au24 SE USB cable connected the computer to the DAC9, and music files were stored on an external Toshiba USB hard drive. Audience Au24 SX balanced interconnects connected the DAC9’s output to ARC’s LS28 line stage.

Linux and Apple’s Macintosh macOS don’t normally need audio drivers to work with USB 2.0, but all versions of Windows do; I had to download and install the DAC9’s Windows USB driver. Installation instructions are available on the website and in the manual. After I’d installed the driver on the computer, it appeared in JRiver as “DAC USB ASIO driver (ASIO),” and I selected it. Since the ASIO driver doesn’t use the DSD over PCM (DoP) protocol to play DSD files, be sure that the box labeled “DSD bitstream in DoP format” remains unchecked.

The Menu buttons on the DAC9’s front panel and remote control take you to the Setup menu. Press Menu several times to step through the various settings. When you get to a setting you want to change, press Option (front panel or remote). After you’ve made the change, press Enter to accept it. Easy! I changed the one feature of the DAC9 I didn’t care for: automatic turn-off, which shuts down the DAC after a specified period (the default setting is two hours). As I said in my review in March 2017 of the LS28 line stage on SoundStage! Hi-Fi, automatic turn-off is great for a coffeemaker, less so for a hi-fi component. Fortunately, it can be turned off entirely, which I did.

The DAC9’s two digital filters, Fast and Slow, can be selected on the fly using the remote, making it easy to compare their effects from the listening position. I preferred the more relaxed sound of the Slow filter, which I used throughout the listening sessions. The filters apply only to PCM recordings, so the obsessive audiophile has relatively few settings to fret over. Sloth that I am, I decided on a single setting and lived with it for the duration, but I can envision the truly obsessive writing down his or her preferred setting for each recording. (Hey, I know about obsession: I reset my cartridge’s vertical tracking angle for each LP I play.)

Audio Research DAC9

Several readers have assured me that the notion of breaking in equipment is some sort of evil conspiracy, but for a long time now ARC has recommended that their gear be broken in for 600 hours -- and, like any competent reviewer, I always follow manufacturers’ recommendations. So I was surprised when I opened the DAC9’s carton and found no page making such a recommendation; apparently, it was scaring people. Here’s what Dave Gordon, ARC’s director of sales, advised: “Generally, the first big break is around 85 hours or so, and the next one is probably closer to 175. It still continues for a few hundred hours, but it is incremental.” Those are still long times, but should assuage your guilt if you start listening before 600 hours are up. For what it’s worth, I broke in the DAC9 for over 600 hours. It took about 500 hours for it to sound its best.


I began with an old standby: “Folia: Rodrigo Martinez,” from La Folia 1490-1701, performed by Jordi Savall and his band of renaissance and baroque specialists (16-bit/44.1kHz AIFF, Alia Vox). This improvisation based on the tune, which was written about 1490, begins with three strokes on the cascabels, or sleigh bells. Many DACs I’ve tried make all three strokes sound identical, but through the DAC9, each was distinct in tonality and in intensity -- a good start. When the rest of the band begins to play, the DAC9 presented a wide-open soundstage with a pure and expansive treble. Details were plentiful but not analytical. The output of busy percussionist Pedro Estevan was audible throughout -- sometimes, his softer passages fade into a background haze. The drum, which descends into the mid-20Hz range, extended quite deeply, but with a smidgen less heft and definition than through the best DACs I’ve heard. Savall’s viola da gamba carries the main melody, and Savall continually varies his loudness and speed, making it challenging for a hi-fi system to follow. The DAC9 didn’t break a sweat, effortlessly capturing even the slightest changes in rhythmic power. The ARC also portrayed a full, accurate harmonic picture of the viola da gamba, further revealing the realism of the recording.

Out came another fave: Shelby Lynne’s Just a Little Lovin’ (DSD64, Lost Highway/Analogue Productions). The title track opens with kick drum, followed by guitar and bass stating the melody. The bass is quite powerful, and the DAC9 captured it realistically, if perhaps a tad less powerfully than some DACs. I suspect the bass level of this download is overdone; the LP sounds more realistic. The DAC9 easily captured the delicate nuances of Lynne’s vocal phrasing; I could more fully appreciate her interpretation of this popular song.

Audio Research DAC9

I followed that recording of a gal with a guitar with one of a guy with a guitar: Neil Diamond’s Dreams (24/192 AIFF, Neil Diamond/ProStudioMasters). A longtime fan of Diamond’s, I’ve been tickled to see him continue to interestingly sing interesting music as he ages (he’s now 76). Primarily a singer-songwriter who performs his own compositions, for Dreams Diamond launched his own eponymous label to offer covers of songs mostly by others, though he sneaks in his own “I’m a Believer.” While I like several songs on this album, I particularly enjoyed his cover of Leonard Cohen’s “Hallelujah,” one of my favorite songs. A gifted poet, Cohen wrote lyrics far more interesting than the insipid verse found in so many songs. The DAC9 accurately captured the many subtle shades of Diamond’s gravelly baritone as he slowly spins this somewhat mystical lyric about music and spirituality -- I think. I don’t know a lot about guitars, but Diamond’s sounds a bit unusual to me, and unlike the many natural guitar recordings I’ve heard: mostly jangly string sound, with little contribution from the guitar’s body. The DAC9 shouldn’t be blamed for that; it reproduced the recording with plentiful detail and harmonic accuracy. But the DAC9 does deserve credit for its portrayal of the music’s urgency and flow, making it easy for me to follow Diamond’s engaging interpretation.

Another review fave is the Tallis Scholars’ recording of Gregorio Allegri’s Miserere (24/96 FLAC, Gimell), an a cappella choral setting of Psalm 51. The performing forces include a solo tenor, the main chorus at the front of the soundstage, and a smaller chorus some distance behind them. The DAC9 spread the main chorus across the entire front of the soundstage, with bloom and air around the image of each chorister. The solo tenor’s voice was free of the wee bit of hardening that some components impose. The small solo group in the distance was clearly separated from the main group, but individual voices in the smaller chorus weren’t as distinct as I’ve heard with a few other DACs. However, the reverberations of the large recording venue, which clearly reveal the size of the space between the two choruses -- an aspect of this recording that some DACs butcher -- was not at all smeared.


For several years, my go-to reference DAC has been PS Audio’s DirectStream ($5999), which unquestionably earns the description innovative. I won’t go into the details of its circuit, except to say it replaces the usual off-the-shelf DAC chip with a field-programmable gate array (FPGA) using code written by digital guru Ted Smith. It also dispenses with an output section; the transformers in the output filter directly drive the interconnects. So there’s no need to debate whether tubes or transistors sound better in the DirectStream’s analog section, because PS Audio uses neither. My favorite feature of the DirectStream is that the operating system used to code the FPGA is upgradable by the user. PS Audio has issued several upgrades to the OS, each of which has made an audible improvement. My DirectStream DAC used the Torreys OS, the latest available at the time of this review. And here’s the best part: all PSA OS upgrades are free.

The DirectStream DAC plays DXD and DSD128 files. Although it won’t play the few DSD256 files currently available, it will convert them to DXD and then play them. PSA’s DirectStream Memory Player is a CD transport that, when connected to the DirectStream DAC via its proprietary I2S input, will also play SACDs. The DirectStream DAC has a built-in volume control, so it can drive one power amp directly, though not two (e.g., a stereo amp and a powered subwoofer). A remote control lets you control the volume, and such DAC functions as digital input selection. An optional digital bridge card plugs into a slot on the back of the DirectStream DAC, to turn it into a streaming network player.

When I began “Folia: Rodrigo Martinez” I heard less difference between the initial strokes on the cascabels, a point in favor of the Audio Research DAC9, but the first bass-drum whack told me the PS Audio DirectStream not only went somewhat deeper in the bass, but had better definition. Then, when Jordi Savall’s viola da gamba entered, I had a stronger impression of someone bowing a stringed instrument, and the playful castanets were more audible throughout. I could also easily follow the fading and swelling of microdynamics that convey the fun these musicians had as they improvised on this ancient tune. “Folia: Rodrigo Martinez” was just more fun to listen to through the PS Audio DAC.

In Shelby Lynne’s cover of “Just a Little Lovin’,” the kick drum and bass that open the song projected more power, impact, and detail with the PS Audio. The differences weren’t subtle -- those instruments reached out and poked me in the chest. Nor was the bass merely weighty; it also had excellent pitch definition. The DirectStream hasn’t always been lauded for its bass performance, but PS Audio’s latest upgrades have improved that. The rest of the percussion also came through with noticeably better transient snap, creating a more believable impression of a drum kit. Then, when Lynne began singing, things got even better. The DirectStream’s reproduction of her voice was deeply engaging, stunningly realistic, and beautifully detailed. Sometimes I have difficulty distinguishing between how two components present this track; in this case, the differences weren’t hard to detect.

Neil Diamond’s cover of “Hallelujah” sounded a bit more organic and natural with the DirectStream. The guitar still sounded a bit weird, but perhaps a little more like most guitars I’ve heard. The sound had a slightly greater sense of physicality, of the singer being present.

The PS Audio presented Allegri’s Miserere with a wide-open sense of space -- if not quite the best I’ve heard, then still a convincing re-creation of a large venue. The PS Audio reproduced the solo tenor with considerable nuance and shading; his excellent enunciation convinced me that if I could speak Latin, I would have easily understood him. The small chorus at the rear of the soundstage sounded more focused and more detailed, and the sense of the space they occupied was more precisely defined.

Bottom line

The DAC8, which preceded the DAC9 in Audio Research’s line, was innovative in its day in having an asynchronous USB 2.0 input capable of playing hi-rez PCM files up to 24/192. Many new DACs that temporarily occupy my rack can play DSD256 files, but the DAC9 plays only up to DSD128. Since few DSD256 files are available as of yet, I don’t think this is a big deal, and it’s clear that ARC has chosen to stick with a proven, conservative approach to digital playback and focus on its core competency: analog circuitry. The addition of tubes to the DAC9’s analog output section is an example of this, and it pays off in the sweet, detailed, organic sound that’s typical of ARC gear.

Audio Research DAC9

I had only two Linux-based music streamers, but if the DAC9’s inability to work with them indicates a general incompatibility with Linux streamers, it means that the DAC9 will be limited to systems in which the source component is a Macintosh or Windows computer -- a limitation, as there are several Linux servers or streamers on the market, and more seem to come along every day. However, I know several audiophiles who spurn any prepackaged server/network player, preferring to optimize their systems’ sound by tweaking the system parameters; if that’s the way you feel, the DAC9’s very good sound quality and gorgeous looks make it an easy recommendation.

. . . Vade Forrester

Associated Equipment

  • Speakers -- Affirm Audio Lumination, Syzygy SLF-870 subwoofers (2)
  • Amplifier-- Berning ZH-230
  • Preamplifier -- Audio Research LS28
  • Digital sources -- Toshiba Satellite laptop computer (i7 processor, 16GB RAM, 1TB hard drive) running 64-bit Windows 10 Home with JRiver Media Center 22; QNAP TS-251 NAS; all servers and digital players connected to PS Audio DirectStream DAC
  • Interconnects -- Audience Au24 SX (balanced and unbalanced), CablePro Freedom (unbalanced), Crystal Cable Piccolo (unbalanced)
  • Speaker cables -- Crimson RM Music Link
  • Power cords -- Audience Au24 SE LP powerChord and powerChord e, Clarity Cables Vortex, Purist Audio Design Venustas
  • Digital link -- Audience Au24 SE USB
  • Power conditioner -- Audience aR6-T

Audio Research Foundation DAC9 Digital-to-Analog Converter
Price: $7500 USD.
Warranty: Three years parts and labor; 90 days, tubes.

Audio Research Corporation
3900 Annapolis Lane N.
Plymouth, MN 55447-5447
Phone: (763) 577-9700


Audio Research responds:

We are aware of the USB interface shortcomings [of the DAC9] and have been working diligently on a replacement interface since we first discovered the limitations late last year. Unfortunately, our original design placed the priority on Windows as our primary platform for validation testing. Moving forward, the focus and majority of our validation testing will be on Linux and macOS platforms. We are committed to releasing an update this year. Original owners who have registered their product will be notified and given preferential treatment.

We are happy to report we recently completed our first round of Linux compatibility testing with a new USB solution. The real challenge is ensuring any new solution we develop will retrofit all of our current products such as the DAC9 as well as much of our legacy product. Our engineering team is working to rectify the issue quickly.

The DAC9 has great architecture and the proof is in the listening. We care deeply about our customer’s happiness and when we find limitations such as this, we take finding a fix very seriously. For those facing these limitations, we recommend the following workarounds:

For macOS platforms: set your player software to only use PCM up to 192kHz

For Linux platforms: use a USB-to-S/PDIF converter such as the Aurender UC100

For Windows platforms: enjoy the full capability of the USB interface

Thank you, again.

Diane Thomas
Director of Marketing