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Wyred 4 Sound DAC-2 Digital-to-Analog Converter
· 15 Dec 10
· Written by Vade Forrester
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S. Andrea Sundaram, a longtime contributor to the SoundStage! Network, recently wrote: “In my own experience, 192kHz files sound noticeably better than 96kHz files. . . .” I took this statement as a challenge; my own experience hadn’t led me to agree.
The Norwegian record label 2L offers a number of files encoded at both 96kHz and 192kHz, and I listened to them. Somewhat to my surprise, there was a difference, and it favored the higher sampling rate. Not only could I hear the difference, but so could a non-audiophile friend who isn’t into computer audio.
So, given that 1) music recorded at the higher sampling rate sounds better, and 2) most computer-based music systems connect to DACs via USB connections, it seems only logical that computing audiophiles will want equipment that lets them play those 176.4 and 192kHz files via USB. But until recently, the USB inputs of DACs were limited to a maximum sampling rate of 96kHz.
Totally Wyred
One of the first high-speed-capable USB DACS to hit the market is the DAC-2 ($1499 USD) from Wyred 4 Sound (who are just as happy being called W4S), which has a solid record of producing power amplifiers and preamplifiers. W4S provides USB 2.0 drivers for 32- or 64-bit Windows XP, Vista, and 7; and for Mac OS 10.4, 10.5, and 10.6.
The DAC-2 is the first high-speed USB DAC I’ve used, and I liked it as soon as I unpacked it; its relatively compactness (8.5”W x 4.5”H x 13.5”D) makes it possible to place next to it another component of similar size on a single shelf of an audio rack. Perhaps your rack doesn’t overflow with gear as mine does, but eventually, almost everyone appreciates some extra space. The DAC-2 is hefty for its size at 16 pounds -- only five pounds less than the Esoteric D-07 DAC I recently reviewed. Another high-speed USB DAC, the Audio Research DAC8, weighs 11.5 pounds, so the DAC-2 is no lightweight.
The appearance of the DAC-2 is in typical W4S style: two slanted end caps, at the left and right ends of the front panel. The DAC-2 is offered in a choice of silver or black for the front, side, and top panels; the end caps are always black. A window in the center of the DAC-2’s front panel houses two blue lines’ worth of vacuum-fluorescent display; these show the input selected, the sample rate of the signal sent to that input, the volume setting, andhow the DAC-2 has been configured. The characters are too small to be read from across the room, but if you’re within arm’s length of the DAC-2, you won’t have to squint to read them. Three buttons on the front panel -- Power, Up, Down -- let you control the volume and turn the DAC-2 on and off.
The DAC-2’s 32-bit digital volume control means it can drive a power amp directly, and with less loss of sound quality than happens with a 24-bit control(all digital volume controls discard bits tosome degree). And because the DAC-2 can thus serve as a system’s preamplifier, a remote control is included for volume Up/Down and all other functions: input selection, balance, muting, phase inversion, etc.
Some DACs won’t play files sampled at 88.2 or 176.4kHz, so one of the first things I checked was that the DAC-2 will indeed play all sampling rates between CD’s 16/44.1 and 24/192kHz. It will.
Inside the DAC-2 is an ESS Sabre Reference (ES9018) 32-bit audio DAC chip and an ESS Time Domain Jitter Eliminator. W4S drew on their experience in designing analog components in using proprietary discrete output stages -- no integrated circuits here. This gives W4S much more control over the precise tolerances of the components used in the DAC-2’s output stage. I like that. Unusually, the digital output and USB boards are upgradeable; if better parts or circuits are developed in the future, the user doesn’t have to get rid of the DAC-2, but can have it upgraded at, presumably, a reasonable cost. I like that, too.
Although the DAC-2’s circuits are fully balanced, many amps and preamps are single-ended, so both types of outputs are provided. There are two coaxial S/PDIF and two TosLink S/PDIF inputs, a single AES/EBU input, and the USB input; so if you have external source components such as tuners with digital outputs (e.g., Bel Canto’s FM1), the DAC-2 can switch among up to four of them.
The DAC-2 also has an I2S input. To quote from colleague Tim Shea’s review of the Stello DA100 Signature DAC and CDT100 transport in our January 2009 issue, “an I2S cable carries the bit clock, word clock, master clock and audio data on their own dedicated conductors rather than bunching them together as on a more typical digital connection. One of the main advantages of this format is that the DAC does not have to recover clock information from the data stream, thus avoiding a common source of jitter.” Although the I2S input is possibly the most advanced type of input on a DAC, there’s no standard format for I2S connectors or wires. But following the example of PS Audio, which uses I2S connections between its Perfect Wave Transport and DAC, in the DAC-2 W4S uses an HDMI connector for its I2S input. The internal wires aren’t used as they would be for a real HDMI cable, but they do allow you to use a DAC-2 with a Perfect Wave Transport instead of PS Audio’s twice-as-expensive Perfect Wave DAC. Clever. The DAC-2’s instruction manual sternly warns you to not, repeat not, connect an HDMI output from a DVD player to the DAC-2. The I2S input is there only to receive the output of a transport or other digital source.
The DAC-2’s USB input uses an asynchronous connection, the preferred way to connect a computer’s USB to a DAC for best sound. Asynchronous means that the computer’s clock is slaved to the DAC’s clock, rather than vice versa. Although such circuits are used in DACs from Ayre Acoustics, Wavelength, HRT, and probably others, those models are highly specialized, with only a single USB input -- if you need S/PDIF and USB connection, you’re out of luck.
The DAC-2’s rated output through its balanced XLR connectors is 5.2V, and 2.6V through its unbalanced RCA jacks, but those levels can be adjusted if need be. The output impedance is 100 ohms -- low enough to drive any competently designed power amp.
Setup and use
I began by installing the 64-bit version of the DAC-2’s drivers in my laptop computer, which runs the 64-bit version of Windows 7 Home Premium. Wyred 4 Sounds’ very well-written manual has clear instructions for how to do this, so I won’t duplicate them here. I connected the laptop to the DAC-2 via a Wireworld Starlight USB cable and used a Wireworld Starlight 6 coaxial cable to connect my Auraliti music server to one of the DAC-2’s S/PDIF inputs. I’ve found that the two devices sound pretty similar. When a manufacturer provides a computer-grade throwaway power cord, I usually do what most audiophiles do and substitute a better, aftermarket cord; but the DAC-2’s stock power cord looked a step, or maybe two steps, above a throwaway cord, so I used it for the review.
W4S recommends 200 hours of break-in, and that’s what I gave the DAC-2, through both its USB and S/PDIF inputs. I know break-in is a pain, but if the manufacturer says it’s necessary, who am I to disagree? But because some members of the anti-break-in crowd claim that a lengthy run-in does nothing but acclimate you to a component’s sound, for good or ill, I don’t listen to a review sample until that period is over, other than to verify that it’s working. That’s what I did with the W4S DAC-2.
Sound
I started by listening to the Wyred 4 Sound DAC-2 with my Auraliti music server via S/PDIF. The first music I played was the Tallis Scholars’ newer recording of Allegri’s Miserere (24/96 FLAC, Gimmell/Gimmell). The soundstage was appropriately huge for the large church in which the performance was recorded. Individual voices were eerily distinct in space, and a smaller choir was obviously placed far behind the main group. The sopranos in this small choir periodically soar up to high C, a dramatic effect that the DAC-2 reproduced with wonderful purity.
The DAC-2 had extended but non-peaky high frequencies. That’s an advantage with speakers such as my Affirm Audio Luminations, which have a slight high-frequency rolloff, but may not be so good with speakers with a rising or peaky high end. As with any component, component matching is important -- nothing new there. The high orchestral chimes that open Eiji Oue and the Minnesota Orchestra’s recording of Argento’s For the Angel Israfel, from Reference Recordings’ 30th Anniversary Sampler (16/44.1 FLAC, Reference/Reference), rang out with unusual purity; I could clearly distinguish the leading transients when the chimes are initially struck.
On the other end of the spectrum, the DAC-2’s bass was deep, powerful, and tight. The bass drum on Folia Rodrigo Martinez (CD, La Folia 1490-1701, Alia Vox AFA 9805) was reproduced with considerable power and weight. The transients of the initial drumstroke were accurately depicted; the event sounded strikingly (sorry) like a drum being struck. It’s not uncommon for a component to smear these strokes, but the DAC-2 didn’t.
The DAC-2’s midrange was pristinely detailed but in no way starkly analytical. Tonal colors were rich and full. In Rebecca Pidgeon’s performance of “Spanish Harlem,” from her The Raven (24/88.2 FLAC, Chesky/HDtracks), nuances of her vocal phrasing were laid out in exquisite detail while still sounding very much like a human soprano, not a hi-fi. Pidgeon, who is also a stage and film actress, invests her singing with lots of interpretive nuance, and the DAC-2 revealed the many shadings in her voice. Bob Katz’s expert remastering of this recording has certainly improved its sound.
Dynamic range could be as powerful or as delicate as the music required. Orchestral climaxes had plenty of slam, but the DAC-2 also accurately tracked the continuous changes in loudness in Folia Rodrigo Martinez, which some components depict as a stair-step series of discrete volume jumps.
Next up was to hear what the DAC-2 could do when connected to my laptop. The only meaningful difference I could reliably hear between my laptop via USB and the Auraliti via S/PDIF was in HF extension: The S/PDIF input had somewhat stronger highs. The chimes in Argento’s For the Angel Israfel were definitely more prominent and better defined. By no means were the highs missing via USB -- they were just a hint less prominent. Those with brighter systems could easily find the USB’s highs more realistic.
The essential equivalence of the DAC-2’s sound through its S/PDIF and USB inputs is a notable achievement. It wasn’t long ago that a reviewer in The Abso!ute Sound declared that all USB inputs were inferior to S/PDIF for musical playback. He may have been right, as far as what he’d heard; however, none of the DACs he sampled had asynchronous USB input. The DAC-2s’s asynchronous USB input essentially equaled its S/PDIF input’s performance -- and both were superb.
Comparisons
The Benchmark DAC1 Pre ($1595) has become a, umm, benchmark against which other DACs are often compared. This US-made product is not only a multiple-input DAC but also a crackerjack headphone amp, and its analog input makes it possible to use it as a preamp. It has a volume control but no remote control; for $300 more, you can get the DAC1 HDR, with remote volume control. Some of the first DACs to offer native 24/96 playback via USB, the Benchmark models have been controversial, earning both raves and pans. So I was anxious to hear for myself how the Benchmark stood up to the W4S DAC-2.
After carefully matching levels between the two DACs, I cued up Folia Rodrigo Martinez. The Benchmark, through its USB input, came across with an energy that made the music sound quite dynamic. Through the W4S DAC-2 I heard equal dynamic range, but instruments were more precisely positioned on the soundstage, and with a smidgen more detail. In other words, the W4S DAC-2 surpassed the Benchmark, while not exactly blowing it into the weeds. The harmonic structure of the opening chimes in For the Angel Israfel was perceptibly better defined through the DAC-2, and I could tell that each striking of a chime was slightly louder than the one before -- something not at all evident with the Benchmark, through which each chime sounded equally loud.
What really distinguished the W4S from the Benchmark was Allegri’s Miserere. Although the Benchmark certainly didn’t hide the fact that this recording was made in a large space, the DAC-2’s soundstage was far better defined, with a sense of depth I’ve seldom heard before, and with each singer in the small ensemble individually identifiable. Wow.
Next, I switched to Benchmark’s S/PDIF input. For this comparison I used the Auraliti music player, which has an S/PDIF output. The Benchmark’s S/PDIF section sounded tonally richer and more spacious than its USB section, but the DAC-2 was slightly richer still, and pinpointed performers more precisely in space.
The way I see it, if a DAC is to be part of a music server that will replace a CD player, then it should sound at least as good as that CD player. So I compared my laptop into the DAC-2 to my vintage Meridian 508.24 CD player, which has long been the best-sounding digital source in my system.