The hottest audio item of 2013 may have been the digital-to-analog converter that will play Direct Stream Digital (DSD) files in their native format, without first converting them to PCM. Why is this a big deal? According to some experts and reviewers, DSD files played without conversion sound better than any form of PCM file. But, as with any hot-button issue in audio, not everyone agrees.
In keeping with my basic audio philosophy of If it sounds good, it’s good, I’ve listened to music files of the same recordings in both DSD and high-resolution PCM, and to my ears, DSD sounds more relaxed and analog-like. It doesn’t mean that high-resolution PCM files sound bad, but that DSD adds another choice to the list of available hi-rez formats. So, for me, DSD is a worthy goal.
But I recommend that you take my -- or any reviewer’s -- word with a grain of salt, and find an audio buddy who can play for you files recorded with both DSD and hi-rez PCM. To make that easier, the Norwegian record label 2L http://www.2l.no) offers sample files in a variety of formats that you can download free. Of course, you’ll need a player and DAC that can play DSD and PCM files. The Luxman DA-06 is just such a DAC.
Luxman is no new kid on the block -- this high-end Japanese company has been a star in the audio firmament since 1925. The DA-06’s introductory price of $6000 USD was recently reduced to $4990, due to changes in the exchange rate. It measures 17.3”W by 3.6”H by 15.7”D and weighs 24.3 pounds, and its silver case looks quite elegant. Be careful: the DA-06’s jewel-like styling and 5/8”-thick faceplate might make the rest of your gear look a bit dowdy.
The DA-06’s front panel looks like those of several other recent Luxman models, with a display about a third of the way in from the right. At the far right is a large knob that lets you select the input. A wide assortment of digital inputs is available: two coaxial S/PDIF, two TosLink S/PDIF, and one AES/EBU, all of which support 24-bit/192kHz PCM signals. In addition, there’s a USB input that supports PCM files up to 32/384, as well as 1-bit/2.8224MHz and 1-bit/5.6448MHz DSD signals (aka DSD64 and DSD128, respectively). If you have any Digital eXtreme Definition (DXD) recordings, you can play them through the USB input. But you can’t play DSD through the S/PDIF input, which I miss, as my Auraliti server will play such files. The DA-06 supports Windows XP or later and Macintosh OS X10.7 or later. Nothing is said about Linux, but my Linux-based Auraliti server had no trouble playing every sort of file -- PCM (even DXD), DSD64, and DSD128 -- via USB.
To the left of the input-selector switch is a small button labeled Digital Out, which toggles the digital output off and on. It doesn’t work for DSD inputs, or inputs with sampling rates of 352.8 or 384kHz. Turning the digital output off is supposed to make the DA-06 sound better in normal use. To the lower left of the Digital Out button is an even smaller button, labeled Display, which changes the display’s brightness through four levels, one of which is off. To the left of that is the display itself. It shows the sampling rate of the incoming signal, whether or not it’s DSD, which filter has been selected, information about the musical selection being played, and, briefly, any changes in the DA-06’s settings. It also has an Unlock indicator, which tells you when the DA-06 is not synchronized with the selected input device. The red LEDs are large and bright enough to be legible from my listening seat, about 10’ from the equipment rack.
To the left of the display is the Enter button, which operates in conjunction with the next three buttons: Filter DSD, which changes the analog rolloff on the DSD output (Filter d-1 is a slow filter, while Filter d-2 is much more abrupt); Filter PCM, which toggles through three interpolation settings of the FIR filter (Normal, Low Latency, and High Attenuation); and Phase Invert, which inverts the phase of the analog output. After you’ve set any of these three, you must then press Enter for that setting to take effect. At the far left of the front panel is the large on/off button, and next to that is the operations indicator: a blue LED that blinks for about ten seconds when the DA-06 is first turned on and is still in mute mode, then glows steadily when the DAC is fully operational.
On the rear panel, from left to right, are: the analog output jacks (two unbalanced RCA, two balanced XLR), the digital input jacks (two coax, two optical, one USB, one AES/EBU), the digital output jacks (coax, optical), and the two-pronged IEC inlet for the detachable power cord. Luxman’s cord lacks a ground pin, but a grounded audiophile power cord should work fine. When the DA-06 is shipped, each input jack is covered with a plastic cap, to keep out dirt. I’ve never seen such a classy feature on any other component, regardless of price. There are also two S/PDIF outputs, which let you use the DA-06 as a USB-to-S/PDIF converter or daisy-chain it to another DAC or digital device.
The DA-06 has dual Burr-Brown PCM1792A chips and a low-phase-noise crystal oscillator for reduced jitter. Like almost all modern DACs, the DA-06’s USB input is asynchronous. The DA-06’s specified output is 2.5V through its balanced or unbalanced outputs, and its output impedance is 300 ohms unbalanced, 600 ohms balanced. The signal/noise ratio is a claimed 124dB, the dynamic range 120dB -- both excellent. There is no volume control; you must use the DA-06 with an external preamplifier or integrated amplifier. And since there’s no volume control, there’s no remote control; I suppose that’s logical, though it would have been nice to have been able to try the different filter settings from my listening chair.
Setup and use
The 17.3”-wide DA-06 slid easily onto a shelf of my equipment rack. I used the stock ungrounded power cord, which didn’t look like the throwaways provided with lots of components. For a source, I used my HP laptop running Windows 7 and JRiver Media Center 19, connected to the DA-06 using a Wireworld Platinum Starlight USB cable. Clarity Cables Organic balanced interconnects connected the DA-06’s output to the Audio Research LS27 line stage. I installed the Windows driver on my laptop computer and reset JRiver's settings to use that driver. Adjusting these settings was very straightforward, presenting no problems or challenges.
The DA-06 switches sampling rates automatically, and also from PCM to DSD and back. There must be a relay inside that changes the display to show you what rate is playing; I heard a soft clunk each time the display changed. That’s a bit unusual -- most DACs change their display silently -- but it had zero effect on the sound quality.
In experimenting with the filter settings, I kinda liked the slow filters, but each of my audio buddies who heard them had his own preference. I left the settings in the default position for the review.
Everything worked smoothly, with no glitches. You’d be surprised how often that doesn’t happen.
Although the Luxman DA-06’s most advanced feature is its ability to play DSD files, it’s just as important to assess how well it played PCM files, including those ripped from CD. After all, what makes up most of your collection? So I played a wide-ranging assortment of music through the DA-06.
A one-word description of the DA-06’s sound is vivid. The harmonic structure of its sound was unusually rich and full -- sometimes, it seemed to just glow. That’s almost reviewer hyperbole, but the harmonic density really was quite high. It didn’t sacrifice detail or transparency, but the sound was just pretty, in the sense that live music is pretty. How often do you hear digital sound described like that? Was that a euphonic effect? To me, the DA-06 sounded more like music than many of the DACs that have passed through my system; but if you prefer a more matter-of-fact sound, the DA-06 may not be your cup of tea.
The bass was deep and detailed, but not as powerful as I’ve heard from a few other DACs. The bass drum in my fave cut Folia: Rodrigo Martínez, from Jordi Savall’s La Folia 1490-1701 (16-bit/44.1kHz AIFF, Alia Vox), went quite low; still, I’ve heard even deeper reproduction of it, and it slightly lacked power and slam. On the other hand, Savall’s viola da gamba sounded quite rich, with string sound to die for. Transients were very well defined; it was easier to discern the impact of the wood blocks being struck than through most DACs, but the effect was not at all over-emphasized. The baroque guitar and the harp, which echo each other’s phrases, were easily distinguished; sometimes, it’s hard to tell them apart.
Piano sound was just exquisite, with realistic dynamics and notes completely defined, from initial transient to full bloom to decay -- as real as anything I’ve heard short of a real piano. With Schubert’s Piano Sonata in A Minor, performed by Thomas Günther (DSD64 DSF, Cybele), the piano had a full sound, rich in detail, in a medium-reverberant space that allowed the notes to fully develop. Günther effortlessly summoned up his instrument’s power, even as the DA-06 realistically portrayed the delicate details of his playing.
Solo guitar was also superbly reproduced. “Shenandoah,” from Alex de Grassi’s Special Event 19 (DSD64 DFF, Blue Coast), sounded unusually rich, and the DA-06 made the drone effect on de Grassi’s guitar shimmer colorfully in the background. This is one of the most detailed recordings of guitar I’ve heard, and the DA-06 fully portrayed the instrument’s entire harmonic spectrum.
The DA-06 also excelled with solo voices. “Spanish Harlem,” from Rebecca Pidgeon’s The Raven (24/176.4 FLAC, Chesky/HDtracks), was utterly pristine and pure. The DA-06 managed to create an illusion of someone standing in front of me and singing, capturing every nuance of Pidgeon’s vocal production. Spooky!
The Tallis Scholars’ recording of Allegri’s Miserere (24/96 FLAC, Gimell) sounded unusually pure and free of distortion. The DA-06 depicted this recording’s depth of soundstage as well as I’ve ever heard it -- the sound of the small group of solo singers some distance behind the main chorus was eerily realistic. With most recordings made in churches or concert halls, as opposed to recording studios, the aural cues that indicate the size of the recording venue were evident without being exaggerated -- just as in a concert.
My Audio Research DAC8 costs only $5 more than the Luxman DA-06, and was one of the first DACs to play 24/192 files through an asynchronous USB input. Like the Luxman, the ARC is strictly solid-state; unlike the DA-06, the DAC8 is fairly light, weighing only 11.5 pounds -- and it plays only PCM files, so I had to limit my comparisons to those. The DAC8 is a perfectly fine-looking component, but it could never be described as audio jewelry. It has a wide assortment of digital inputs, balanced and unbalanced outputs, and front-panel lights that indicate the input selected and the sampling rate of the file being played. And there’s a remote, so you can switch among inputs. But, again, there’s no volume control -- as with the DA-06, the DAC8 must be used with an external amp or line stage. I guess it’s just a coincidence that both Luxman and ARC offer complete ranges of line stages . . .
The DAC8 slightly emphasized the higher end of the audioband, whereas the DA-06 marginally favored the midrange and upper bass. This created the impression that the Luxman’s sound was very slightly richer.
One difference between these DACs that was not subtle was the deep bass: The ARC’s was stronger and weightier. When I played Folia: Rodrigo Martínez, it sounded as if my subwoofer was turned on. It wasn’t -- I was also evaluating a power amplifier, and I needed to assess how it covered the entire audioband. The DA-06’s bass was just as deep and detailed, but lacked the ARC’s power and slam. Actually, the DAC8 has perhaps the strongest deep bass output of any DAC I’ve tried, including some costing twice as much -- for some systems, it may have too much bass. That probably destroys any vestige of credibility I may have had; I can imagine many audiophiles wondering, “How can you have too much bass?”
Rebecca Pidgeon sounded just as clean and pure through the DAC8 as through the DA-06. The double bass may have sounded a bit more powerful through the ARC, but it was very close. Otherwise, this recording was pretty much a toss-up.
Allegri’s Miserere sounded a bit different through these DACs. Again, the DA-06 very slightly emphasized the midrange and upper bass, and sounded just a bit cleaner than the DAC8, with slightly less noise -- though until this comparison, I’d never thought of the ARC as being “noisy.” Both DACs did a splendid job of capturing this recording’s soundstage, but the DA-06 sounded just a tad more spacious.
Both DACs sounded excellent. For some, the ARC’s deep bass performance could make the difference, one way or the other. But the DAC8 doesn’t do DSD, and it looks a bit plain compared to the DA-06.
There are now many DSD-capable DACs available, and more appear monthly -- trying to assess the Luxman DA-06’s value is like shooting at a moving target. Still, it seems to me that the DA-06 sets the standard for sound quality at its price. Its build quality earns an A+, its cosmetics a solid A. The DA-06’s vivid, colorful sound enhanced whatever recordings I played through it, from DSD64 to “Red Book” -- just for old times’ sake, I spun a couple of CDs through the Luxman, and they, too, sounded great. The DA-06’s wide assortment of digital inputs make it compatible with just about any digital source device, and with all commercially available digital file formats in use as of the end of 2013. I understand that Luxman plans to release DAC models at prices lower and higher than the DA-06’s $4990, but for me, for now, the DA-06 represents a peak on the value scale.
. . . Vade Forrester
- Speakers -- Affirm Audio Lumination
- Amplifier -- Berning ZH-230
- Preamplifier -- Audio Research PH5 phono, Audio Research LS27 line stage
- Analog sources -- Linn LP12 turntable on custom isolation base, Graham Engineering 2.2 tonearm, van den Hul Platinum Frog cartridge, Sony XDR-F1HD tuner (Radio X modified)
- Digital sources -- Hewlett-Packard dv7-3188cl laptop computer running Windows 7 Home Premium (64-bit) and JRiver Music Center 19; Auraliti PK100 music server; all servers and digital players connected to an Audio Research DAC8 DAC
- Interconnects -- Clarity Cables Organic, Audience Au24 e (balanced), Purist Audio Design Venustas (unbalanced), Wireworld Cable Gold Eclipse 7 (balanced)
- Speaker cables -- Clarity Cables Organic
- Power cords -- Purist Audio Design Venustas, Blue Marble Audio Blue Lightning, Clarity Cables Vortex, Audience powerChord e
- Digital cables -- Wireworld Platinum Starlight USB and Gold Starlight 6 S/PDIF
- Power conditioner -- IsoTek EVO3 Sirius
Luxman DA-06 Digital-to-Analog Converter
Price: $4990 USD.
Warranty: Three years parts and labor.
1-3-1 Shin-Yokohama Kouhoku-ku,
North American distributor:
Luxman America Inc.
27 Kent Street, Suite 122
Ballston Spa, NY
Phone: (518) 261-6464