- Category: Feature Articles
- Created on Wednesday, 01 September 2010 00:00
- Written by Jeff Fritz
More and more audiophiles are migrating from CD-based audio systems to computer sources capable of higher resolutions. We now know, definitively, that greater resolution and higher fidelity are available with properly implemented computer setups than with CD players. There is no comparison between 16-bit/44.1kHz CD and files with higher sampling rates and longer word lengths, such as 24/88.2, 24/96, 24/176.4, and 24/192. If you’re stuck with CD resolution, you aren’t hearing the best that digital audio has to offer.
We also know that you can get high resolution -- i.e., a music file in any resolution greater than the CD standard of 16/44.1 -- from both Windows- and Mac-based computer systems. There are many ways to get a digital signal out to external digital-to-analog converters, but since I use a Mac, that’s what I’ll focus on here.
One of the critical elements in setting up a Mac-based music server is using third-party software to override Apple’s Core Audio, as used in concert with iTunes. Programs such as Sonic Studio’s Amarra 2.0, which I use, and Channel D’s Pure Music, facilitate listening to hi-rez files at their native sampling rates without you having to manually adjust your computer’s settings each time you switch between resolutions (for instance, from 16/44.1 to 24/96). The use of one of these programs is mandatory for the improvements in ergonomics and sound quality they make possible: Amarra definitely sounds better than iTunes alone, and I’ve heard that the same is true for Pure Music (which I haven’t yet tried).
There are two options for outputting digital signals of up to 24/192 from a Mac computer: FireWire and USB. If you have a Mac, you’ll have to choose one of these, then continue in that direction with the rest of your purchasing decisions -- I’m unaware of any DAC on the market that has hi-rez FireWire and USB inputs. Which is better? As with most things, it depends on whom you ask. Proponents of USB, specifically asynchronous USB, will tell you that their method transfers digital signals with extremely low levels of jitter. In the simplest terms, asynchronous transfer (not to be confused with asynchronous sample-rate conversion), means that the DAC controls the timing of the data sent from the computer to the DAC, thereby lessening timing errors, aka jitter. The Ayre Acoustics QB-9 DAC ($2500 USD) -- which should be capable of 24/192 by the time you read this, up from 24/96 -- has won very positive press for its sound quality, though it has just one digital input, on USB. A couple of other asynchronous USB DACs are now or will soon be available at a retailer near you.
And if you choose FireWire, the products from Weiss Engineering will surely enter the picture.
Daniel Weiss has been in the audio business a long time. He began working for the Swiss company Studer-ReVox in the early 1980s. He founded his own company, Weiss Engineering, in 1985, and introduced a number of professional audio products. In 2001 he began to design and make high-end audio components for consumers, and ever since, Weiss’s products have been raved about in audiophile circles. The DAC202 digital-to-analog converter ($6670) succeeds the highly acclaimed Minerva DAC, which I reviewed in October 2008, and which we named Ultra Audio’s Product of the Year. The DAC202 is not an update of the Minerva platform (which is shared by a pro-audio variant, the still-current DAC2), but is, according to Weiss, a completely new model.
Physically, the DAC202 is compact and fairly lightweight (7.4"W x 3.1"H x 11.7"D, and about ten pounds). A rectangular LCD screen on the front panel gives the user any number of readings: input, sampling frequency, volume level, filter type, and polarity are all displayed by default. A push of the single rotary knob on the right grants access to the DAC202’s menu system and several operational parameters that can be adjusted: the input selection can be changed, the filter slope can be adjusted between A and B (A has a steeper digital filter, B a more gradual rolloff), and the volume control can be engaged or disengaged, etc. A headphone jack, IR remote sensor, and standby LED round out the nicely finished aluminum front panel.
The rear panel is fairly busy for a DAC. The DAC202’s primary way of interfacing with a Mac computer is through FireWire, of which there are two connections. The DAC202 also sports S/PDIF and single- or dual-wire AES/EBU (RCA or XLR), and TosLink digital inputs as well, all capable of handling 24/192 signals. In addition to those digital inputs are BNC input/output connectors for connecting an external word clock. The digital outputs include RCA, XLR, and FireWire, which would let you use the DAC202 as a digital-to-digital converter. For instance, you could send FireWire to the DAC202, then send the digital output via XLR to a DAC that lacks the facilities to interface with a Mac for hi-rez audio (though I’m not sure why you’d do this, after spending $6670 on the DAC202). The RCA and XLR analog outputs can be configured as fixed or variable: the DAC202 has an internal volume control, so you can bypass your preamp if you have only digital sources. This volume control is implemented in a unique way: you first adjust coarse settings in the analog domain, then fine settings in the digital domain; you then use the latter as your main method of adjusting volume. This hybrid analog/digital circuit is employed so that no resolution is lost, as it would be with an all-digital volume control.
The internal details include two DACs per channel to improve the signal/noise ratio, and a very low-impedance analog output stage. As for jitter rejection, Weiss states that he addresses jitter created in the DAC202’s internal signal path and the signal path coming from the source, in my case a computer. Internal jitter, he says, is suppressed via "good old analog design principles . . . such as shielding from electric or magnetic fields, good grounding, good power-supply decoupling, [and] good signal transmission between the clock generator and the actual D/A chip. "As for externally generated jitter, Weiss uses a two-stage phase-locked loop (PLL) circuit, which he defines as a "control system with error feedback. "According to him, this is effective at suppressing jitter in both the very high and low frequencies: "The DAC202 is virtually immune to the quality of the audio source regarding jitter. "How do FireWire and Weiss’s jitter-suppression system compare with asynchronous USB? I can’t say, and this is an area in which a number of highly reliable experts disagree. Weiss does state, however, that "the DAC202 also uses async data transfer, i.e. the DAC202 is the master clock for the computer."
The DAC202 is as rich in features as any DAC I’ve used. For example, to ensure that you’re getting an unadulterated hi-rez digital signal out of your computer, you’re advised to use the DAC202’s bit-transparency check. From an included CD, you load into your music library a series of files representing various resolutions: 24/88.2, 24/96, all the way up to 24/192. You then play these tracks, and the DAC202 indicates on its front panel whether or not each resolution has been preserved with bit-perfect integrity; i.e., not altered by sample-rate conversion, equalizers, or digital volume controls. This very reassuring feature gives you confidence that you’re hearing all that’s available from your digital audio system.
The DAC202 comes with a mid-sized remote control of metal with a simple but effective design: you can directly access each digital input without scrolling through all of them, control the volume, reverse polarity, and switch digital filters on the fly. (I mildly preferred Filter B, though the effect of switching was subtle.) There’s a lot more to the DAC202, and it comes with one of the most comprehensive owner’s manuals I’ve ever seen for an audio product.
The Weiss DAC202 sounded cleaner than any other DAC I’ve heard, letting me hear deeper into good recordings than I had previously thought possible. An example was Carla Lother’s 100 Lovers (24/96 AIFF, Chesky/HDtracks). Her jazz-pop vocal style, along with the upbeat accompaniment of guitar, bass, drums, and various stringed instruments, make this a recording with diverse musical and sonic qualities. "Let’s Grow Old" is chock-full of these, and the Weiss DAC202 kept each one carved out in space within the soundstage. At the same time, the song was all of a piece; in other words, the pace and timing remained just perfect. Coupled with the Weiss’s ultraclean background, this realistic view into the very natures of Lother’s voice and the instruments around her made for a very involving musical experience.
The Weiss DAC202 was tonally dead neutral, as you might expect from a modern high-end electronic component. What differentiated it from other tonally neutral products, however, was how richly developed its tonal palette was. Remember, tonally neutral doesn’t always mean tonally perfect. For instance, tracks with multiple, diverse-sounding singers illustrated the DAC202’s ability to differentiate among them in the mix, allowing me to easily locate them precisely on the soundstage. The tiny nuances of inflection that made each singer distinct were clearly rendered -- again, tonally rich sound.
Listening to the Persuasions’ "Angel of Harlem," from The Ultimate Demonstration Disc Volume 2 (24/96 AIFF, Chesky/HDtracks), was ear-opening for the ultratransparent way the Weiss DAC202 and my system painted the soundstage in front of me with delicate perfection and spot-on scale. The soundstage itself was ultrawide and exceptionally deep. This was the tennis-match effect in the extreme: As the performance unfolded, I looked and listened from one side of the room to the other. This went beyond simple detail within the soundstage, having more to do with extremely small microgradations that defined every dimension of the soundstage. The DAC202 made my mental mapping of the soundstage less challenging. This is one area in which the Weiss got closer to re-creating the feel of a live performance than any other source component I’ve heard in my system.
The DAC202’s reproduction of transients was also razor-sharp. The Weiss was the antithesis of syrupy and colored; fast and neutral, it never descended into etched or bright sound. I found it very easy to listen to -- partly, I feel, because it let so much information pass through. While really raucous material could bombard me with sound, I could just as easily get lost in softer mixes that let me forget all about digital or analog sound: the experience simply made me want to listen longer.
As stated above, nothing stood out as a frequency-response aberration through the DAC202. Bass was deep and solid, while highs were ultra-extended and, when the recording called for it, airy and ethereal. The midrange could sound magical, and Beat Kaestli’s Invitation (24/88.2 AIFF, Chesky/HDtracks) was a prime example. I could hear deeper into his voice than I have been able to with perhaps any other recording of a male singer that I can remember. The stand-up bass in "It Could Happen to You" was singularly articulate, and the texture and projection of Kaestli’s voice was breathtaking to behold. His relaxed singing style made me want to listen more, and that, in turn, relaxed me. This combination of resolution and enjoyment is a large part of what being an audiophile is all about, and this recording through the DAC202 brought it all home.
One afternoon, after a particularly long session with hi-rez music, I listened to a number of my reference CD tracks, to hear how the DAC202 would hold up with 16/44.1 recordings. I found myself disappointed with the recordings while being impressed with the DAC202’s handling of them. It was as if I was hearing everything those CDs had to offer, but that it was just shy of everything I’m confident the original recordings could offer if heard as higher-resolution files. There were some notable exceptions, such as Keb’ Mo’ singing "Every Morning," from his 1994 self-titled CD (Epic 57863). His guitar was sharply rendered, with great transient attack that made the instrument sound as "plucky" as could be. His voice was crystal clear and tonally neutral, even if I couldn’t hear the texture of his voice as fully as I could with the voices in the higher-resolution tracks in my collection.
There are many good standalone audio DACs on the market today. But some are clearly designed for 16/44.1 playback, whether via a CD transport or computer, whereas others are primarily intended to interface with computers for hi-rez playback. An example of the former is the Accustic Arts DAC-II SE, recently reviewed in Ultra Audio, which is limited to 16/48. The Simaudio Moon Evolution 750D will handle higher resolutions on most of its digital inputs -- up to 24/192 -- but its USB input is limited to 16/48. Although these products sound fantastic in their own rights, and handle CD-rez music as well as anything I’ve heard, their lack of support for Mac owners wanting a direct path by which to send hi-rez digital from computer to DAC makes them nonstarters for many. There are digital converters on the market that will convert a USB or FireWire signal to S/PDIF for use with any number of DACs. But the audiophile in me is hesitant to add another device to the chain if I don’t have to.
Which leaves us with a number of USB DACs that will support 24/192, such as the Ayre QB-9, the Wyrd 4 Sound DAC2, and the Audio Research DAC 8 -- alternatives to the Weiss products that should be explored. You could easily argue that the Weiss DAC202 has an advantage over the others listed in that, in terms of handling hi-rez digital audio, it’s a second-generation product. You could also make a case for the Ayre being the most sensible choice for, among other things, its incredibly competitive price of $2500. Either way, to determine which works best for your system you’ll have to listen to them, and consider their features and input capabilities. As for me, the Weiss costs little more than half as much as the Accustic Arts and Simaudio models I’ve had here recently, and offers far better support for the Mac user wanting to listen to hi-rez audio files. And who among us doesn’t want to listen to hi-rez? We’re audiophiles!
All things considered, the Weiss DAC202 is the best-sounding DAC I’ve had in my system. It’s a match for the best I’ve heard with "Red Book" CD files, and eclipses anything else I’ve used when listening to music at greater-than-CD resolution. I’ve never heard better sound through my audio system than when listening to hi-rez recordings through the DAC202.
This means that the DAC202, and perhaps a few other DACs, embodies the current state of the art of digital audio. Its features, such as its bit-transparency check and selectable digital filters, along with a host of input options, also make it one of the most flexible DACs on the market today. Its sound with CD is equal to that of the best DACs I’ve heard, some of which cost much more, and its performance with high-resolution audio up to 24/192 is the best I’ve ever heard. If you can cough up $6670 for a DAC, and if you want to explore the outer reaches of sound quality with a hi-rez computer-based source, then the Weiss DAC202 should be at the top of your must-audition list.
. . . Jeff Fritz
The World’s Best Audio System, September 2010
- Speakers -- Rockport Technologies Arrakis
- Amplifier -- Boulder Amplifiers 2060
- Preamplifier -- Boulder Amplifiers 1010
- Source -- Apple MacBook running iTunes and Amarra 2.0
- Cables and power conditioning -- All Shunyata Research: Aurora-IC interconnects, Aurora-SP speaker cables, Hydra V-Ray II power conditioner; Anaconda Helix Alpha/VX, Python Helix Alpha/VX, Taipan Helix Alpha/VX power cords
Manufacturer contact information
Weiss Engineering Ltd.
8610 Uster / Zurich
Phone: +41 44-940-20-06
Fax: +41 44-940-22-14