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- Written by Erich Wetzel Erich Wetzel
- Category: Full-Length Equipment Reviews Full-Length Equipment Reviews
- Created: 01 March 2018 01 March 2018
Schiit Audio was founded in 2010 by two audio veterans: Jason Stoddard, formerly of Sumo, and Mike Moffat, formerly of Theta Digital. In the 1980s, Theta was one of high-end digital’s pioneers, and Moffat was behind all of their designs. All of Schiit’s equipment is manufactured in Valencia, California, using parts mostly sourced from the US. They also have a retail shop, The Schiitr, in Newhall, California, where the public can drop in to see and hear their gear. The jokes and puns on Schiit.com aside (read it, it’s hilarious), these guys take their audio seriously.
In Norse mythology, Yggdrasil (pronounced IG-druh-sill) is an evergreen ash tree that holds in its branches the nine worlds. Schiit’s Yggdrasil, the company’s flagship digital-to-analog converter, is known informally among Schiiters as “Yggy,” and is sold direct from the Schiit factory for $2399 USD (Analog 2 included). According to Schiit, it’s also the “best DAC [we] know how to build . . . Well, without a second mortgage and 50-amp power runs.” It comes with a 15-day money-back guarantee and a five-year warranty.
The Yggdrasil is solidly built, weighs 25 pounds, and measures 16”W x 3.9”H x 12”D, including its little rubber feet -- but what first drew my attention was its attractive case. A sheet of silvery, 0.162”-thick anodized aluminum starts at the top rear, is bent down in front to create the faceplate, then is bent back again to form the bottom plate -- viewed from the side, it looks like a hardback book bound in metal. This book’s cover encloses the Yggy’s innards in the dark gray, 0.063”-thick, folded-steel chassis and the rest of the case, the latter visible as the side and rear panels. The high build tolerances are evinced by virtually invisible gaps everywhere metal meets metal, as I discovered when I took a closer look and saw that the wraparound “book cover” is not made of a single sheet -- the separate bottom panel is stepped into it. Countersunk machine screws at the top of the aluminum faceplate secure it to the sheet steel behind and below it and add a bit of flash to the Yggy’s appearance. The manufacturer and model names are modestly indicated on the top and front panels. From across the room, I found the combination of silver, white, and dark gray quite appealing.
There are only two buttons on the Yggy’s front panel, for Phase Invert and Input, and their action had a terrific feel. White LEDs indicate phase-inversion status, the input selected, the sample rate, and when to “buy better gear.” That last indicates when the input clock is running in a lower-quality mode because of excessive jitter or poor centering frequency in the input signal. There are separate LEDs for sample rates of 44.1 and 48kHz, and for multipliers of those rates by 1, 2, 4, and 8. As the Yggy accepts signal resolutions of only up to 24-bit/192kHz, the 8x indicator is currently unused (but may be activated in the future, given the right updates).
The Yggdrasil is a modular design, and while I had the review sample Schiit released and sent along an update, Analog 2, on two circuit boards. Owners of original Yggdrasils can upgrade to Analog 2 status for $550, though that requires sending the unit back to Schiit or an authorized service center. When I opened the case to install the Analog 2 boards -- each of the two channels, left and right, gets its own board -- I discovered that upgrading the DAC is easy (see Comparison, below). Each major section of the Yggdrasil’s circuitry occupies its own board, attached to an interconnection and power-distribution board that underlies the other boards. I easily figured out which circuit boards were for USB, the DAC section, and various other input and output sections.
On the rear panel are the inputs -- asynchronous USB, AES/EBU, BNC, coax, and TosLink optical -- and analog outputs: two pairs single-ended (RCA), one pair balanced (XLR). There are also an IEC power inlet and an on/off switch.
One area in which Schiit.com does not make snarky remarks is in its presentation of technical details. The Yggy has separate transformers for its digital and analog stages. The balanced and single-ended analog circuits are built on discrete JFET buffers, and JFETs are also used to combine the balanced signal for single-ended output. The frequency responses of the analog circuit are specified as 20Hz-20kHz, +/-0.1dB, and 0.5Hz-200kHz, -1dB.
The Yggdrasil has four Analog Devices AD5791BRUZ integrated circuits for converting digital signals to analog: two per channel. What’s very different about the Yggy compared to most modern DACs is the 20-bit ladder-DAC architecture of the AD5791. To some, 20 bits will seem a throwback to the 1980s and early 1990s, before 24 bits became the norm and delta-sigma converters took over -- today, even 32 bits is bandied about. It’s also why, in their ads for the Yggdrasil, Schiit jokingly describes it as “obsolete.” But they make a good point in stating that no 24-bit recording actually has 24 bits’ worth of resolution (equivalent to 144dB of dynamic range). They claim that 19.5 bits is the very best that most recordings can do.
Often considered the simplest DAC architecture, a ladder DAC uses a series of resistors -- one for each bit in a digital word. The value of each bit, 0 or 1, turns each resistor off or on, and the combination produces the desired voltage. That seems simple enough. The problem is that the resistor values must be incredibly precise to ensure that each bit difference is exactly double as you move higher (or one half if you move lower), which is extremely difficult to achieve due to small errors in the manufacturing. In the 1980s, companies such as Denon hand-trimmed resistor values to ensure tight tolerances; I’m not sure how Schiit does it. Maybe the tolerances for ladder DACs are now tighter?
Digital filtering is handled by a proprietary “closed-form” filter that runs on an Analog Devices SHARC DSP processor. This filter, Schiit claims, interpolates, as all filters do, but “retains all the original samples,” something they say other filters don’t do. Schiit says that it took Mike Moffat five years to “perfect this digital filter, involving 1917 Western Electric papers on pulse-code modulation, a professor emeritus of mathematics who devised a way to get around the divide-by-zero problem, a RAND Corp mathematician to implement it, and a master programmer to get it to run on our SHARC processor engine.”
Clock regeneration is said to be bit-perfect across all sample rates. Schiit indicates that their Adapticlock method is “the most sophisticated clock regeneration scheme in the industry.” One thing the Yggdrasil can’t do is decode DSD. Schiit prefers to include sophisticated multibit decoding, as is found in all their standalone DACs, and custom clocking and filters, rather than the ability to process a format that’s not used all that frequently. Other significant specs include a total harmonic distortion (THD) of less than 0.005% from 20Hz to 20kHz at full output, and a signal/noise ratio of more than 119dB, referenced to 2V RMS.
There wasn’t much to setting up the Yggdrasil in my system. While it has two pairs of single-ended RCA outputs, the manual implies that the balanced output provides the better sound, so that’s what I used. In that respect, the Yggy was a perfect DAC for my system. It’s solely a DAC, with a fixed output of 4.0V via its balanced XLR jacks (2.0V via the single-ended RCAs) and no built-in volume control. I wired the Yggy to my iMac computer, running iTunes and Tidal HiFi, via a Nordost Blue Heaven LS USB link. My Hegel Music Systems P20 preamplifier received analog signals from the Yggdrasil, then sent them on to my Audio Research D300 amplifier via Dynamique Audio Shadow balanced interconnects. The ARC delivered power through Transparent Audio MusicWave Ultra speaker cables to KEF R900 loudspeakers.
After all was hooked up, the Yggy fortunately did not inform me that I needed to “buy better gear.” I was all set to listen. I did all of my evaluative listening with the Analog 2 boards.
The Yggdrasil consumes 35W, and was never more than warm to the touch during its time here, despite never being powered down and having no cooling vents.
Throughout the Presto agitato of Beethoven’s Piano Sonata No.14 in C-sharp Minor, Op.27 No.2, “Moonlight,” in the 1992 recording by Maurizio Pollini (16-bit/44.1kHz AIFF, Deutsche Grammophon), the Schiit Yggdrasil reproduced Pollini’s rapid playing so spectacularly that I thought I was going to wind up with repetitive-stress disorder in my fingers. The transitions from silence to hammers striking strings back to silence were instantaneous as Pollini clattered up and down the keyboard. The transients were faster than I’m used to. Similarly impressive were the decays as the movement wound down and Pollini’s playing became less intense. Sustained notes were audible for longer before disappearing altogether.
Of course, while both of these things were going on, Pollini was also playing runs of staccato notes up and down the keyboard, but the Yggy presented both abrupt transients and prolonged sustains with ease. The Schiit’s clarity of sound throughout the piano’s range was impressive. From the mechanical, drawn-out rumble of Pollini’s left-hand notes to the tinkling shortness of the notes at the far right of the keyboard, no note or tone was emphasized or shortchanged, and, most important, no note blurred into its neighbors.
I cued up Natalie Merchant’s Tigerlily (16/44.1 AIFF, Elektra) and sampled tracks until I got caught up in her singing of “Seven Years.” The Yggy presented Merchant’s powerful voice in so lifelike a manner that I was transfixed by its stereo image, centered in front of my listening chair. Her forceful singing filled my room with life, and what felt like the purest tones ever emitted by a pair of vocal cords. I’d never heard a voice so well reproduced by my system, let alone by a DAC anywhere near the Yggdrasil’s price. Merchant’s sibilants never sizzled or lingered too long; rather, they faded away naturally. I heard no digital exuberance in her voice, just a compelling naturalness; she was alive. Cellist Michelle Kinney’s notes were so brilliantly embodied that I could practically see the rosin snowing off her bow, and I felt her bow’s slow, stuttering progress across the strings. The drums in this recording were also more lifelike through the Yggy than I’m accustomed to hearing from my reference system: fleshed out, down to the nuances of soft touches on skins, rattles of wires on the snare, and that physical pop you feel when you stand in front of a kick drum.
I love the space in “One Perfect Sunrise,” from Orbital’s Blue Album, as well as its fun pace (16/44.1 ALAC, ATO). The Yggdrasil projected a soundstage that stretched the full width of my room, despite my speakers’ outer edges being a couple of feet from the sidewalls. Though this stage was holographic, it didn’t reach forward into the room; on the contrary, it was slightly laid-back, with outstanding depth that helped the voices in this track feel especially live. Spatially, the Yggy added little that wasn’t already in the recordings I played -- not a criticism, of course. “One Perfect Sunrise” itself is a laid-back recording, and sat almost entirely behind my speakers. Placements on the soundstage were excellent, allowing me to shift my attention to whichever part of the performance I desired. Much as it had with Natalie Merchant’s, the Yggy placed a strong, clear image of Lisa Gerrard’s voice at the center of Orbital’s ethereal electronic mix.
The sound of Eric Clapton’s Unplugged (16/44.1 AIFF, Reprise) is a little raw, and was instructive in my listening to the Schiit Yggdrasil. “Alberta” begins with a fun error on Clapton’s part. He’d played the previous song with a slide on his hand, and had begun “Alberta” while still wearing it. Realizing the problem, he stops his band -- “’ang on, ’ang on, ’ang on, ’ang on” -- removes the slide, and starts over. Through the Yggy, the few notes he plays with the slide sounded notably different from the ones played without slide just a few seconds later. Through the Schiit, the twang and additional vibrato jumped out much more vividly than I’d ever heard them through my system. I could also better hear the difference of the sound of Clapton’s pick against his guitar’s thinner, tauter, straight strings from its sound when striking the lower-pitched, wound strings. These types of details kept bringing me back to the descriptor clear. Everything I played through the Schiit sounded clearer and more detailed than I’d heard it in the past.
All of the clarity, balanced tonality, spacious soundstaging, precise imaging, slightly laid-back feel, and outstanding vocals made listening through the Yggdrasil fun and entertaining. Real voices, real instruments, and real spaces all added up to very musical experiences. The Schiit Yggdrasil is the most “analog”-sounding DAC I’ve ever had in my system.
Comparing Schiit’s Analog 1 and Analog 2 circuit boards required that I disassemble the Yggdrasil’s case, disconnect the ribbon connector to the front-panel controls without somehow damaging it, swap out the boards, and put it all back together. I think I had to remove and reinstall a total of 45 screws.
The change from Analog 1 to 2 provided a solid improvement in sound. Pollini’s piano and Merchant’s voice were now more sharply clear, while the midbass and bass content of Orbital’s “One Perfect Sunrise” and the drums in the other tracks were all tighter and better controlled. The Analog 2 circuits also subtly relieved a bit of brightness in the treble of Pollini’s piano and Clapton’s closely miked acoustic guitar in “Alberta.” Overall, the Analog 2 circuits tightened up the already excellent sound I heard with the Analog 1 boards. Do I think the $550 would be a worthwhile investment for owners of original Yggys? Absolutely.
My reference DAC is Benchmark Media Systems’ DAC2 HGC ($1995). Like Schiit, Benchmark sells factory direct, so the DAC2 HGC offers a strong point of comparison with the Yggdrasil. Listening to the Schiit and Benchmark back to back, I was surprised by what I heard. The Yggdrasil was notably more musical; the Benchmark sounded brighter at the top end and, while still firm in the bass, was less impactful. The two DACs’ imaging and soundstaging were similar, but the Schiit felt more in-the-flesh than the Benchmark. The Yggdrasil sounded more natural than the DAC2 HGC, which sounded somewhat mechanical -- or, dare I say it, more digital by comparison.
Because of the Yggdrasil’s clearly superior sound, I felt that the comparison with the Benchmark was somewhat unfair. Hans Wetzel, my brother (I’m better looking) and a fellow SoundStage! reviewer, suggested that I find something more “accomplished” to compare to the Schiit DAC. He let me borrow Hegel Music Systems’ flagship DAC, the HD30 ($4800).
As I had the Benchmark DAC2 HGC, I installed the Hegel HD30 with its output fixed at line level. I noted much subtler differences between the sounds of the Schiit and Hegel, despite the fact that the latter costs twice the former’s price. The Hegel had a slightly more open top end, music sounding a little airier and brighter than in the Yggy’s more even sound. The considerable treble content of Clapton’s “Alberta” best demonstrated this, though the track began to feel a bit too bright after a couple of plays through the HD30. Natalie Merchant’s slightly sullen singing also lightened up a bit through the Hegel. The HD30’s soundstages were even bigger than the Yggdrasil’s, particularly with Pollini’s recording of the “Moonlight” -- the piano sounded wider through the Hegel. Likewise, Orbital’s already expansive “One Perfect Sunrise” was wider and deeper through the Hegel. The HD30 presented a bit more bass slam than the Yggdrasil, but less of the clarity and transient impact that I grew to love from the Schiit. Ultimately, the $4800 Hegel proved no better than the $2399 Schiit -- just a bit different.
Schiit Audio was founded and is run by seasoned audio veterans committed to building high-quality hardware, a commitment evidenced by their flagship digital-to-analog converter’s five-year warranty. In its Analog 2 version, the Yggdrasil DAC marries affordability to exceptional sound quality courtesy a bespoke DAC architecture from one of hi-fi’s most pioneering digital designers. The Yggdrasil provided beautiful, musical sound even when fed challenging recordings from digital’s early days. Clear imaging, large and solid soundstaging, linear frequency response, and a particularly fabulous midrange all make the Schiit Yggdrasil an excellent DAC at any price.
. . . Erich Wetzel
- Loudspeakers -- KEF R900
- Preamplifier -- Hegel Music Systems P20
- Amplifier -- Audio Research D300
- Source -- Apple iMac running Mac OS 10.11.6, iTunes, and Tidal HiFi
- Digital-to-analog converters -- Benchmark Media Systems DAC2 HGC, Hegel Music Systems HD30
- Speaker cables -- Transparent Audio MusicWave Ultra
- Analog interconnects -- Dynamique Audio Shadow XLR, Transparent Audio MusicLink Super RCA
- USB link -- Nordost Blue Heaven LS
Schiit Audio Yggdrasil Digital-to-Analog Converter with Analog 2 Upgrade
Price: $2399 USD; Analog 2 upgrade for original Yggdrasil, $550 USD.
Warranty: Five years parts and labor.
24900 Anza Drive, Unit A
Valencia, CA 91355
Phone: (323) 230-0079