Jump to content
  • The Computer Audiophile
    The Computer Audiophile

    Weiss Engineering DAC202 Review

    DAC202-front-thumb.jpgOver the last couple years I’ve listened to people utter the phrase, “I’m waiting to see how it all shakes out." Without context it’s entirely appropriate to assume we were discussing the global economic meltdown. However these conversations revolved around music servers, interfaces, and differing computer audio technologies. People were frequently delaying the purchase of a new DAC because of their uncertainty about the future of the marketplace. Specifically uncertainty about interfaces such as USB, FireWire, Ethernet, AES/EBU, and S/PDIF. These interface options have caused serious hesitation from the same people who eagerly accepted Compact Disc technology as if it offered perfect sound forever. Equally hesitant are audiophiles feeling a bit burned by SACD and DVD-Audio. Audiophiles shouldn’t let the past halt their potential heightened enjoyment of this wonderful hobby. There’s no format war going on. Many different interfaces and technologies will flourish in the years to come. Falling victim to <a href="http://en.wikipedia.org/wiki/Analysis_paralysis">analysis paralysis</a> or suffering from <a href="http://www.urbandictionary.com/define.php?term=Alligator%20arms">alligator arms</a> are two easily curable conditions. Ambivalent audiophiles, It’s time to <a href="http://en.wikipedia.org/w/index.php?title=Fish_or_cut_bait&redirect=no">fish or cut bait</a>.

    [PRBREAK][/PRBREAK]

     

     

     

    <b>What’s The Hold Up?</b>

     

    There’s little doubt that computer based audio is the future of high end playback. In a nod to <a href="http://www.youtube.com/watch?v=Kn6uqwSjDjY">Rusty and Audrey Griswold</a>, the only remaining question is “Are we there yet?" The answer to that question is yes, as long as the right combination of software and hardware are selected. The perpetual naysayers who won’t be satisfied until a music server is easier to operate than a toaster should also look at a traditional dCS system with three or four separate boxes and say the spinning disk isn’t there yet because they can’t operate the dCS system with these ease of a cassette player. I’ve never heard anyone suggest the latter and I don’t see why the argument should hold true when it comes to music servers. Music servers, like most technology, can be placed on a continuum from simple to complex. Logical factors in the “Are we there yet" analysis should be related to sound quality, sample rate support, feature sets, interface design, and bit transparency.

     

    What does all this have to do with the Weiss Engineering DAC202? The DAC202 could easily be the component to knock audiophiles off the fence and on to the next phase of high end audio. The DAC202 may be the best antidote for the aforementioned audiophiles suffering from alligator arms and analysis paralysis. The sound quality, sample rate support, feature set, interface design, and bit transparency testing built into the DAC202 should satisfy audiophiles from the most jaded old schooler to the early adopters looking to replace an existing DAC.

     

    <b>Weiss Engineering DC202 Evolution And Lineage</b>

     

    Computer audiophiles who’ve been using music servers for weeks, months, and years are likely familiar with the name Weiss Engineering and eponym Daniel Weiss. Professional engineers, even more familiar with Daniel Weiss, have used his components for decades. In fact a recent visit to Paul Stubblebine Mastering in San Francisco demonstrated Weiss Engineering’s penetration into the “audiophile" facilities where many of our favorite albums are mastered. Needless to say Daniel Weiss is one of the best engineers in the business at designing components that have made and played high quality music.

     

     

    <a href="http://images.computeraudiophile.com/graphics/2010/0617/Stubblebine/IMG_0178.JPG" class="thickbox" rel="stubblebine"><img src="http://images.computeraudiophile.com/graphics/2010/0617/Stubblebine/IMG_0178-small.jpg"></a>   <a href="http://images.computeraudiophile.com/graphics/2010/0617/Stubblebine/IMG_0179.JPG" class="thickbox" rel="stubblebine"><img src="http://images.computeraudiophile.com/graphics/2010/0617/Stubblebine/IMG_0179-small.jpg"></a>   <a href="http://images.computeraudiophile.com/graphics/2010/0617/Stubblebine/IMG_0180.JPG" class="thickbox" rel="stubblebine"><img src="http://images.computeraudiophile.com/graphics/2010/0617/Stubblebine/IMG_0180-small.jpg"></a>   <a href="http://images.computeraudiophile.com/graphics/2010/0617/Stubblebine/IMG_0181.JPG" class="thickbox" rel="stubblebine"><img src="http://images.computeraudiophile.com/graphics/2010/0617/Stubblebine/IMG_0181-small.jpg"></a>   <a href="http://images.computeraudiophile.com/graphics/2010/0617/Stubblebine/IMG_0182.JPG" class="thickbox" rel="stubblebine"><img src="http://images.computeraudiophile.com/graphics/2010/0617/Stubblebine/IMG_0182-small.jpg"></a>   <a href="http://images.computeraudiophile.com/graphics/2010/0617/Stubblebine/IMG_0183.JPG" class="thickbox" rel="stubblebine"><img src="http://images.computeraudiophile.com/graphics/2010/0617/Stubblebine/IMG_0183-small.jpg"></a>   <a href="http://images.computeraudiophile.com/graphics/2010/0617/Stubblebine/IMG_0184.JPG" class="thickbox" rel="stubblebine"><img src="http://images.computeraudiophile.com/graphics/2010/0617/Stubblebine/IMG_0184-small.jpg"></a>

     

     

     

    In June 2008 I reviewed DAC202 predecessor the <a href="http://www.computeraudiophile.com/weiss-engineering-minerva-firewire-dac-review">Minerva</a>. It was a great component but at the time options for computer audiophiles were much more limited. The Minerva was a big fish swimming in a little pond. That certainly doesn’t diminish the Minerva’s performance but it places proper perspective on my assessment. In December of the same year I reviewed the Berkeley Audio Design <a href="http://www.computeraudiophile.com/Berkeley-Audio-Design-Alpha-DAC-Review">Alpha DAC</a> and subsequently crowned it my favorite DAC. I placed the Alpha above the Minerva for a few reasons namely soundstage, volume control / preamp capability*, HDCD indicator**, and sample rate display.

     

    Nearly two years later Weiss Engineering has responded in true leapfrog fashion. The DAC202 was not built to equal the competition or as a minor tweak of the Minerva. The DAC202 was built to surpass the competition and previous Weiss DACs. After investing well over two hundred hours actively listening through the DAC202 in every sensible configuration I unequivocally state Weiss Engineering has handily surpassed the competition and all previous Weiss DACs in its class.

     

    <FONT SIZE="-2">* At the time of review the Minerva did not have volume control. Weiss Engineering did enable volume control in later releases of the Minerva, but the implementation was clearly an afterthought and awkward to use.</font>

    <FONT SIZE="-2">** The HDCD indicator on the Alpha DAC is a rudimentary indication of bit transparent audio reproduction. When playing an HDCD encoded file the indicator should illuminate. If the indicator remains dark this signifies playback is not bit transparent. However, there remains a slim chance that the indicator will illuminate without bit transparent playback. In other words, if the indicator is off and it should be on something is wrong. If the indicator is on there is a good chance playback is bit transparent, but bit transparency is not guaranteed. I have successfully played an HDCD encoded file that produced major distortion and short drop-outs yet consistently illuminated the HDCD indicator. Thus the rudimentary categorization of the HDCD indicator. </font>

     

    <b>Weiss Engineering DAC202 In Detail</b>

     

    At $6,670 USD the Weiss DAC202 has increased in price as much as performance over its predecessors. I’ll leave judgements of value up to individual readers as each of our monetary decisions involve vastly different variables. I will say a significant percentage of audiophiles have spent many times the amount of the DAC202 price premium on “upgrades" with far less overall impact.

     

    <img src="http://images.computeraudiophile.com/graphics/2010/0617/index-66.jpg" style="padding: 5pt 10pt 5pt 5pt;" align="left">The <b>fit and finish</b> of the DAC202 has been improved nicely over previous Weiss DACs. The new headphone socket, volume control, and LCD display elevate the look of this unit to the audiophile standard. The Minerva and to a much greater extent the DAC2 look very utilitarian even though their lackluster form doesn't enable enhanced function. The rear of the DAC202, although very compact, is laid out ergonomically. I had no problems during the review period inserting and removing all types of cables. The addition of a gold headphone socket to the DAC202 raises the versatility of the unit to another level. Most manufacturers don’t offer a headphone output on products at this price point. Weiss Engineering has wisely considered the continually growing high quality headphone market with the inclusion of a standard quarter-inch (<b>T</b>ip, <b>R</b>ing, and <b>S</b>leeve connector) headphone output. The addition of a rotary encoder knob, referred to here as a volume control, was a must not only to improve upon previous designs but to enable menu navigation with ease. The knob itself is of high quality and spins in the overly obvious clockwise and counter-clockwise directions using detents for every half or full db adjustment. These detents, unlike the new Antelope Zodiac DAC controls, enable the listener to recall an exact volume level when desired. In addition the volume control is used to select menu items by pushing the knob inward. The DAC202’s three inch LCD display (measured diagonally) is somewhat easy to see from a nine to twelve foot listening position and a appropriately understated when when automatically dimmed. Significant information such as volume level, phase, and filter are easily visible while the active interface and sample rate may be more difficult for some listeners to read at a distance. The display is nicely recessed into the solid aluminium faceplate. This faceplate that will also be available in black once the second production run is underway. The DAC202 ships with a nicely built substantial but not over engineered remote control. After a few hours of use the important buttons such as volume and power can be memorized as they are not lost in a sea of useless buttons. The DAC202 remote offer ten buttons, all of them either discreet or toggle selectors with the exception of volume up and down. It’s very nice to select a specific interface instead of scrolling through the list of available interfaces.

     

     

    <center><a href="http://images.computeraudiophile.com/graphics/2010/0617/DAC202-front-large.jpeg" class="thickbox" rel="dac202-hardware"><img src="http://images.computeraudiophile.com/graphics/2010/0617/DAC202-front-small.jpeg"></a>   <a href="http://images.computeraudiophile.com/graphics/2010/0617/DAC202-back-large.jpeg" class="thickbox" rel="dac202-hardware"><img src="http://images.computeraudiophile.com/graphics/2010/0617/DAC202-back-small.jpeg"></a></center>

     

     

     

    The <b>feature set and technical capabilities</b> of the Weiss DAC202 are extremely good. Directly addressing three of the four reasons I previously selected the Alpha over the Minerva are the new volume control, bit transparency check, and seemingly mundane sample rate display. In addition to these three features and capabilities the Weiss DAC202 offers a critically and consumer acclaimed asynchronous FireWire interface. The DAC is also capable of sending word clock out to an audio card in an asynchronous-like fashion. Either way the Weiss DAC202 retains the critical role of master clock.

     

    <a href="http://images.computeraudiophile.com/graphics/2010/0617/dac202-remote-large.jpeg" class="thickbox" rel="dac202-hardware"><img src="http://images.computeraudiophile.com/graphics/2010/0617/dac202-remote-small.jpeg"style="padding: 5pt 10pt 5pt 5pt;" align="left"></a>More and more audio systems consist of digital only sources and are less dependant on a traditional preamplifier. Digital to Analog converters with <b>volume control</b> have thus become increasingly popular. In 90% of audio systems this popularity (bypassing an analog preamp) serves the system well. It’s a rare occasion when inserting a preamp improves sound quality but it does happen. The volume control implemented in the Weiss DAC202 may increase that percentage to 99% because of its flexibility and superior design. The DAC202 features a coarse analog / fine digital volume control on both the main and headphone outputs. The DAC is capable of four selectable coarse settings via relay in the analog domain and fine level adjustments in the digital domain. Listeners who insist on using a preamp can defeat this level control on the main output only. One of the beauties of coarse analog level control is the capability to closely match the input sensitivity of an amplifier. My McIntosh MC275 has a sensitivity of 1.2 volts via unbalanced RCA inputs and 2.5 volts via balanced XLR inputs. Using the balanced XLR outputs of the DAC202 I set the coarse analog level to 2.12v With a closely matched voltage setting the digital volume attenuation does not have degrade the sound quality like it can with an unmatched pair of components. This matching allows use of the digital volume control over its entire range. The maximum bearable listening volume is reached at 0 db, not a level near -12 db of attenuation. For example a DAC with fixed output voltage of 6v feeding 2.5v MC275 power amplifiers will require either a preamp or major volume attenuation at the DAC to achieve proper listening levels. DACs with well implemented 32 bit or 24 bit digital only volume controls and proper dithering techniques can handle quite a bit of attenuation without deleterious effects to the sound quality <a href="http://files.computeraudiophile.com/2010/0617/Digital_Level_Control.pdf">[Digital Level Control PDF]</a>. However a coarse analog / fine digital volume control allows the ideal balance of analog voltage matching with limited or no digital attenuation or sonic degradation. The 7.6 db difference between 6v and 2.5v may seem minimal at first blush, but consider the difference just 1 db can make during listening evaluations. The DAC202’s four selectable coarse analog settings are 1.06, 2.12, 4.15, and 8.15v. The fine digital level adjustments are full db steps from -60 db through -20 db and half db steps for levels between - 20 db and 0 db of attenuation. The coarse analog / fine digital volume control is by far my favorite feature of the Weiss DAC202.

     

    A very popular question on the Computer Audiophile forum is, “How do I check for bit transparent output?" Until recently a true test of bit transparency required very expensive and sophisticated engineering test equipment. Now this test can be accomplished with a couple mouse clicks and absolutely no engineering knowledge. The Weiss DAC202 features a <b>built-in bit transparency check</b> that works in conjunction with Weiss Engineering supplied test WAV files. This feature is easily the most underrated and most needed feature in all of computer based high end audio. If the source signal is not perfect there’s no way to make it perfect down the line. Sound quality can only get worse when starting with a sample rate converted or reduced bit depth digital signal. Bit transparency is akin to playing lossless files. Most people easily realize the sonic consequences of ripping, storing, and playing lossy MP3 files. But, many people don’t realize when their bits are butchered because they’ve never heard their system produce bit transparent audio. Depending on the level of processing done to the digital signal by the computer operating system or playback application there may be no difference between the sound quality of a lossy MP3 and heavily processed non-transparent digital signal [bit opaque :~)] . Perhaps injured equally by the lack of bit transparency in user’s systems are the DAC manufacturers. Countless times I’ve talked to people who’ve completely written off great sounding DACs because of perceived poor sound quality. Yet these same users had no way of knowing if playback was bit transparent. Judging the quality of a component further down the chain with irreversibly broken, terribly processed music is a disservice to the listener, the manufacture, and anyone who comes in contact with the user’s opinion whether verbal or written online. The Alpha DAC has its HDCD indicator and as I’ve already mentioned it’s far from infallible. The Weiss DAC202’s built-in bit transparency check works because Weiss Engineering supplies audiophiles with the test audio files. The DAC202 is programmed to look for the exact bit pattern delivered in these files only when playback is bit transparent. Running the bit transparency check is quite simple. All that’s required is setting the DAC to a specific sample rate, selecting Run from the Transparency Menu on the LCD, and playing one of the test files from a computer. When playback is bit transparent the DAC202 indicates the bit depth of the given test file either 16 or 24 bits. If something on the computer isn’t configured correctly the DAC202 simply displays the word Fail. I tried to trick the DAC202 into displaying the bit transparent indicator, but I was unsuccessful after many attempts. Weiss Engineering supplies test files in both 16 and 24 bit word lengths at 44.1, 48, 88.2, 96, 176.4, 192 kHz sample rates.

     

    The third feature that formerly put the Alpha DAC over the top is a simple <b>sample rate display</b>. This seemingly mundane feature can actually help indicate software configuration problems on the fly. Displaying the sample rate of the current track is far from a perfect way to indicate bit transparency, but it’s a step in the belt and suspenders direction. This feature is mainly helpful when an audio output device such as the DAC202 is not configured for Exclusive Output Mode in Windows Vista or 7. As I recommended in my <a href="http://www.computeraudiophile.com/content/Windows-7-Audio-J-River-Media-Center-14-Configuration">Windows 7 / J River Media Center</a> article, it’s wise to set the default Windows sample rate to something like 24 bit, 48000 Hz (Studio Quality). This default format is only used in Shared Output Mode as opposed to Exclusive Output Mode. Shared Output Mode equals compromised sound quality for audiophiles. Thus, when there is an output mode software misconfiguration the Weiss DAC202 clearly indicates 48kHz on the front LCD display no matter what sample rate is actually being played. Since there is virtually no content available at 24/48kHz this is a nice indication that something is wrong.

     

    In high end audio master clocking has traditionally been reserved for the extremely exclusive components from companies like <i>d</i>CS and Esoteric. Now that computer based audio continues to gain in popularity more audiophiles are able to experience and afford a properly master clocked system via asynchronous interfaces on D to A converters. The Weiss DAC202 FireWire interface, when used in conjunction with the internal DAC202 word clock, operates asynchronously. This means the DAC202 is the master clock when playing files from a computer. Currently asynchronous interfaces are all the rage and rightly so. <b>Asynchronous transfer mode</b> can reduce timing inaccuracies by a factor of 100 in well designed DACs. The sonic benefits of certain asynchronous interfaces are well documented by listeners the world over. These positive listening experiences are also backed by solid engineering principals. In the simplest terms timing is critical to the reproduction of recorded sound involving digital to analog conversion. More accurate timing can produce more accurate sound. As of this writing all DACs using FireWire interfaces require third party software to function. The Weiss DAC202 uses a Dice FireWire chip from <a href="http://www.tcelectronic.com/">TC Electronic</a>. Weiss Engineering supplies the Dice software on a CD with the DAC202 and offers the newest versions of the Dice software via its website (password required). Installation of this software is simple frequently requiring a couple clicks and a restart. This software is completely independent of all playback applications like iTunes and J River Media Center, and doesn’t require user intervention after installation. It’s also very important to note that not all devices with FireWire interfaces operate asynchronously like the Weiss DAC202.

     

    In addition to using the DAC202 via asynchronous FireWire in master clock mode it’s possible to use the DAC202 as the <b>master clock</b> with high quality audio cards such as the Lynx AES16, RME HDSPe AES, and Merging Mykerinos. Many engineers that I’ve talked to about word clocking suggest the master clock should remain as close to the DAC as possible. Yet others are adamant about externally clocking all digital devices with a separate word clock. The DAC202 can accommodate either configuration as it offers word clock input and output. When using the word clock output the DAC202 is the master clock and sends a word clock signal to the audio card. These “slaved" audio cards are simply configured to acquire clocking information from an external source instead of using an internal clock. This method keeps the word clock as close to the DAC as possible in an asynchronous-like fashion. Listening through the Weiss DAC202 for hundreds of hours I determined this configuration sounded nearly as good as using the FireWire interface. More on that later. Like all good DAC designs the Weiss DAC202’s audio interfaces are all galvanically isolated. The BNC word clock input is not galvanically isolated.

     

    Two <b>additional differences</b> between the Minerva and the DAC202 are the newly designed analog output stages and newly designed D to A converter. Peaking inside the DAC202 one can see the nicely segregated main analog output stage. The DAC202 offers separate output stages for the main and headphone outputs. Weiss elected to use very good operational amplifiers (opamps) with a high slew rate, and a low impedance topology. According to Daniel this makes the DAC202 even more impervious to cabling and impedance mismatches between DAC and amplifier. The new redesigned D to A converter uses two converters per channel as well as separate converters for the main and headphone outputs.

     

    <b>Using The Weiss Engineering DAC202</b>

     

    There are a number of <b>DAC202 options</b> available via the front LCD display. The DAC202 User Manual is very thorough and offers a detailed technical description of each of the following options. Here is a list of the options in order and some of my notes that correspond to each option.

     

    <b>Main Screen</b>

    <ul>

    <li>Volume: -60 db to 0 db

    Full or half db steps depending on attenuation level. Matching my MC275 input voltage allowed me to listen at or near 0 db.</li>

    <li>Input Source: FireWire, AES (XLR), SPDIF (RCA), SPDIF (TOS)

    Changing the digital source is easily accomplished via the discrete remote commands, and is available via the front panel. This is done right on the main screen without any menu navigation. Software switching of the input source is not available.</li>

    <li>Sample Rate Indicator: 44.1, 48, 88.2, 96, 176.4, 192 kHz

    The sample rate cannot be changed as this is simply an indicator of the current sample rate.</li>

     

    <b>Options Menu</b>

    <li>Abs. Phase: + or -</li>

    <li>Upsample Filt.: A or B</li>

    <li>Sync Source: XLR, RCA, Toslink, WC BNC, 1394 Bus, Internal

    When using the FireWire input I use the Internal word clock exclusively. The 1394 Bus option is only used when multiple DAC202s are connected to the same computer via FireWire. One DAC would be set to Internal and the other would be slaved by setting its sync source to 1394 Bus. Using Lynx AES16 and AES16e audio cards I used both the Internal and WC BNC sync sources. Using the Lynx to send clock to the DAC202 (WC BNC) is not recommended when other options are available. The reverse, sending clock to the Lynx from the DAC is very good sounding. I also set the sync source to XLR but the auto sample rate adjustments by the DAC202 necessitate a one to two second mute while the DAC changes rates. Missing the first couple second of a track can get annoying.

    <li>Sync Rate: 44.1, 48, 88.2, 96, 176.4, 192 kHz

    This option switches the sample rate of the DAC. Manually navigating the menu is the slowest way to accomplish these changes when not running in an auto sample rate switching mode. The simplest method of changing the sample rate is via the Weiss software interface. Simply click the drop-down menu and select the desired rate. The software interface requires a FireWire connection operate although the FireWire interface doesn’t have to be used for audio. During my listening sessions with the Lynx cards running into the DAC202 via AES I always used the Weiss software interface to change the sample rate. It really made no sense to have an XLR connection if a FireWire connection is already present, but this shows the ease of which the software interface works.</li>

    <li>LCD Bright: 0-30 (15)

    I used the 15 setting as it was just bright enough to read in my rather dark listening room. This setting is only active while the LCD is in use for menu navigation or when a setting on the panel (Volume, Sample Rate) is changed. The LCD switches to the LCD Dim Level after around ten seconds.</li>

    <li>LCD Dim Lev.: 0-15 (0)

    I used this setting at 0 as I had no need to continually read the display. During settings changes the LCD illuminates so there is no need, other than aesthetic, to keep the Dim Level above 0.</li>

    <li>Dual WIre: Enabled or Disabled

    Not used for this review. The DAC202 handles all sample rates via single wire.</li>

    <li>DW WCLK: Halfrate or Audiorate

    Set to Audiorate during this review.</li>

    <li>Insert Mode: Disabled, ret. XLR, ret. RCA, ret. TOS

    This is a anti-audiophile option more likely to be used by professionals. It enabled the insertion of external devices like equalizers between the source and the DAC.</li>

    <li>Main Out Att.: Engaged or Bypassed

    I used the Engaged setting exclusively as I had no need to use a preamp between the DAC202 and amp. When set to bypassed the main volume attenuation does not work.</li>

    <li>XLR Out Lev.: 1.06, 2.12, 4.15, 8.15

    This is the very nice coarse analog setting for the main output. As I stated earlier the MC275 sensitivity is 2.5v so I set this level to 2.12.</li>

    <li>Phones Lev.: 0.2, 0.9, 5.2

    This is the coarse analog setting for the headphone output. The default is 0.2v. I used Sennheiser HD600 headphones during the review. these headphones required the 2.7v setting for comfortable listening levels while keeping full use of the fine digital volume control.</li>

    <li>Transparency: Run or Stop

    This is where the built-in transparency check is run. Selecting the Run setting and playing a Weiss supplied file is all that’s required. It’s very easy to use, but was not extremely intuitive. I did have to read the manual.</li>

     

    <b>System Info</b>

    <li>Firmware ver: 1.0.0.3</li>

    <li>SDK Version: 3.5.3.8786</li>

    <li>Model DAC_202 (0x7)</li>

    <li>Weiss OUID: 23</li>

    </ul>

     

    <b>Music Servers, Storage, And Source Material</b>

     

    During the review period I used three main music servers and three types of storage. Two Windows 7 machines, one Mac OS X computer, a NAS drive, external bus powered drive, and internal SSD.

    <ol>

    <li>The Computer Audiophile Pocket Server (C.A.P.S.) <a href="http://www.computeraudiophile.com/content/Computer-Audiophile-Pocket-Server-CAPS">[Details]</a> Since the C.A.P.S. machine does not have a FireWire port I purchased an internal PCI FireWire card to connect to the DAC202. Some CA readers have reported issues using certain FireWire chipsets. The card I purchased uses the VIA 6307 PCI to FireWire IEEE1394a controller chip and worked flawless. There was no software installation required under Windows 7. The card is manufactured by SYBA, model number SD-VIA-FW1E1H. The best part about this card is the $7.99 price from NewEgg <a href="http://www.newegg.com/Product/Product.aspx?Item=N82E16815124034">[Link]</a>. This card offers a single external FireWire 400 port and a single internal FireWire 400 header to connect a FireWire port to the computer case if necessary.

    <li>MacBook Pro 13" [Model Identifier: MacBookPro5,5] running Mac OS X 10.6.3 and 10.6.4 Snow Leopard. An Intel Core 2 Duo processor running at 2.26 GHz and 4 GB of RAM. The internal Solid State Drive (SSD) is a 120 GB OCZ Vertex Turbo (MLC). Amarra version 2.0, iTunes 9.2 (61), and Songbird 1.7.3 Build 1700. To connect the DAC202 I started by using a noname FireWire 800 to 400 converter and a Monster Cable FireWire 400 to 400 (6 pin to 6 pin) cable. Most of my listening through this MacBook was done on battery power only and wired Ethernet or no network connection at all.</li>

    <li>MacBook Pro 13" [Model Identifier: MacBookPro5,5] running Windows 7 Ultimate 32 Bit. An Intel Core 2 Duo processor running at 2.26 GHz and 4 GB of RAM. The internal Solid State Drive (SSD) is a 120 GB OCZ Vertex Turbo (MLC). J River Media Center v14 and v15. Started using a noname FireWire 800 to 400 converter. After a few issues where the DAC202 disappeared from the computer I switched to a single FireWire 800 to 400 cable. This did not resolve the issue 100% but I am currently unable to reproduce the issue at the time of this writing. The issue was only present under Windows 7. According the Weiss FireWire software the following informatioin is available about the drivers and FireWire chipset in my MacBook Pro. Drivers - Microsoft 1394ohci.sys [6.1.7600.16385], Microsoft ohci1394.sys [6.1.7600.16385] (legacy), Microsoft 1394bus.sys [6.1.7600.16385] (legacy). I tried all three even though they look awfully similar. OHCI 1394 Host Controller - Vendor : (11C1) LSI (Agere, Lucent), Chipset: (5901) FW643, Revision: 07, Status : Active, Details: Subsysten VendorId: 11c1, Subsystem DeviceId: 5900, Max # isoch Rx contexts: 8, Max # isoch Tx contexts: 8, Max 1394 Speed Capability: S800, Support: Compatible, no known issues. Most of my listening through this MacBook was done on battery power only and wired Ethernet or no network connection at all.</li>

    <li>I used three different NAS drives during this review. A. Thecus N5200B Pro, B. QNAP TS-559 Turbo NAS Pro, and C. Synology DS710+.</li>

    <li>The external drive used was an Oyen Digital MiniPro 750GB 5400RPM External 2.5-in FireWire 800/400, USB Portable Hard Drive <a href="http://oyendigital.com/hard-drives/store/CB2-54-750-M.html">[Link]</a>. This drive is powered from the USB or FireWire bus and uses the Oxford 934 chipset (OXUF934SSA). A switching power supply is available but not recommended for high end audio applications. I had success using the daisy chain capability of FireWire when connecting this FireWire 800 drive directly to the MacBook Pro and connecting the DAC202 via FireWire 400 to 800 cable to the drive. Note the faster FireWire devices should be connected closer to the computer when daisy chaining with devices of differing speeds.</li>

    </ol>

     

    Much of the source material used during this review was either 16/44.1 kHz or 24/96 kHz, with a small dusting of 24/176.4 kHz HRx material. 90% of the files were encoded in FLAC and copied to memory before playback in J River Media Center. The main Windows audio output method used was WASAPI. ASIO and Kernel Streaming both worked just as good as WASAPI through JRMC v15. I was unable to discern a sonic difference during the review period between either of the three output methods.

     

    During the course of the review I up the firmware and Weiss software once. The process was simple. A rare software bug that only manifest itself under a twisted concoction of configuration changes was fixed and there was no change in sound quality.

     

     

    <a href="http://images.computeraudiophile.com/graphics/2010/0617/weiss001.PNG" class="thickbox" rel="dac202"><img src="http://images.computeraudiophile.com/graphics/2010/0617/weiss001-small.png"></a>   <a href="http://images.computeraudiophile.com/graphics/2010/0617/weiss002.PNG" class="thickbox" rel="dac202"><img src="http://images.computeraudiophile.com/graphics/2010/0617/weiss002-small.png"></a>   <a href="http://images.computeraudiophile.com/graphics/2010/0617/weiss003a.PNG" class="thickbox" rel="dac202"><img src="http://images.computeraudiophile.com/graphics/2010/0617/weiss003a-small.png"></a>   <a href="http://images.computeraudiophile.com/graphics/2010/0617/weiss004a.PNG" class="thickbox" rel="dac202"><img src="http://images.computeraudiophile.com/graphics/2010/0617/weiss004a-small.png"></a>   <a href="http://images.computeraudiophile.com/graphics/2010/0617/weiss005.PNG" class="thickbox" rel="dac202"><img src="http://images.computeraudiophile.com/graphics/2010/0617/weiss005-small.png"></a>   <a href="http://images.computeraudiophile.com/graphics/2010/0617/weiss006.PNG" class="thickbox" rel="dac202"><img src="http://images.computeraudiophile.com/graphics/2010/0617/weiss006-small.png"></a>   <a href="http://images.computeraudiophile.com/graphics/2010/0617/weiss003b.PNG" class="thickbox" rel="dac202"><img src="http://images.computeraudiophile.com/graphics/2010/0617/weiss003b-small.png"></a>   <a href="http://images.computeraudiophile.com/graphics/2010/0617/weiss004b.PNG" class="thickbox" rel="dac202"><img src="http://images.computeraudiophile.com/graphics/2010/0617/weiss004b-small.png"></a>

     

     

     

    <b>Weiss DAC202 Sound Quality</b>

     

    During the several weeks I spent listening to the DAC202 there was nothing more I wanted to talk about then its sound quality. I enjoyed being contacted by Weiss dealers, who had yet to receive their DAC202s, to discuss how good this DAC sounds. The DAC202 actually takes the cake for the component I’ve spent the most time listening through. Even after removing my reviewer’s hat for the evening I often felt compelled to listen to more music. I’ve had other components in here that enabled me to listen to a lot of music, but nothing like the DAC202 that compelled me to listen. Listening critically to more music that sounds fabulous elevates the whole experience to another level. It seems like every time I listened it was critical and in a good way. I was sucked into the music, yet I could explain the detail that I was hearing in every instrument. At no time did I listen to the DAC202 and get sidetracked by life’s daily distractions. After listening to several other components over the years I clearly remember not being able to answer sound quality questions until I sat down with a notebook and scratched a few words on paper. The music definitely leaves an imprint on one’s mind when listening through the DAC202.

     

    The two sonic characteristics that won’t leave my mind for a long time are full, vibrant, and cohesive soundstage, and fabulous, full, nonbloated, midrange that’s to die for. The aforementioned adjectives are what the music sounds through the DAC202, not what the DAC202 sounds like. It just doesn’t seem right to discuss the sound of a component when the music is all I could thinnk about. I won’t even suggest the DAC202 is without a sonic signature. In fact all of this describes its sonic signature. It’s just that the music is what sticks in my head. The DAC202 has a way of presenting the music instead of presenting itself. Listening to the 24/96 download of <a href="https://www.hdtracks.com/index.php?file=catalogdetail&valbum_code=HD00731454330428">Ella and Louis</a> over and over again caused me to chuckle a bit in my listening chair. When something sounds good it’s hard not to get giddy. The coherency and illusionary image presented when listening to this album was astounding. Shelby Lynne’s new album <a href="http://www.amazon.com/Tears-Lies-Alibis-Shelby-Lynne/dp/B0039ZF86E/ref=sr_1_1?ie=UTF8&s=music&qid=1276821794&sr=1-1">Tears, Lies, and Alibis</a>, mixed by Al Schmitt at Capitol Studios in Hollywood and mastered by Doug Sax & Sonny Nam at the Mastering Lab in Ojai, California, sounded superb through the DAC202. I felt as though I could hear everything. Like nothing was really between me and the music. The midrange detail that came through reminded me of the Shelby Lynne concert I attended May 2nd, 2010 at the small Dakota Bar and Grill in Minneapolis. In no way was my system producing sound as real as the concert, but the thought to compare live v. recorded Shelby Lynne entered my mind several times.

     

    Since the DAC202 supports all reasonable sample rates including 176.4 and 192 I could listen to my Reference Recordings HRx material in its native resolution. My go-to album Crown Imperial by the Dallas Wind Symphony (<a href="http://www.referencerecordings.com/HRxORDER.asp">HR-112</a>) revealed a bit more about the Weiss DAC202. The higher frequencies are smooth yet accurate as far as I can tell. This smoothness is possibly rounding the leading edge of transients. I say possibly because my McIntosh MC275 tube amplifier isn’t known for tack sharp transients and ear piercing pings. The bottom and mid to lower frequencies appeared to be right-on. I didn’t notice any annoying bass exaggeration or emphasis. I’m guessing the low jitter FireWire interface has a lot to do with this low end clarity and appropriate punch. Listening to Marcus Miller’s Silver Rain album, specifically track one, through the Weiss DAC202 is enough to solidify anyone’s opinion that this DAC has great control in the bottom end.

     

    The best sounding interface to listen through was FireWire. Using a Lynx AES16 card into the DAC202’s AES/EBU input and slaved to the DAC202’s word clock was a close second place. The externally clocked Lynx configuration just wasn’t as cohesive as listening through the FireWire interface. The Lynx was a bit sloppy sounding. Plus, the FireWire interface is incredibly convenient compared to a Lynx card and only requires a computer with a FireWire port not a PCI slot.

     

    The fourth factor I considered back in December 2008 that sunk the Minerva in my mythical rankings was its soundstage. In the Alpha DAC review I said, <i>“In my opinion the major sonic difference between the two [Alpha and Minerva] is soundstage...The Minerva has a much more focused soundstage that may be narrow to some listeners. On the other hand this focussed and tight soundstage is exactly what some listeners are seeking. In a way the Minerva is like plugging into the soundboard to make a live recording and the Alpha DAC is like placing microphones elsewhere in the venue. “</i> Comparing the soundstage of the Alpha to that of the DAC202 was almost painful for me. The Alpha has been my old faithful for a couple years. It’s always been an overachiever. After listening to the DAC202 for long enough it was time to face the music. The DAC202 has a much more cohesive soundstage than the Alpha and has lost any overly narrow characteristics present in the Minerva. Comparing recording after recording revealed the same results. The appropriately sized and high cohesivity of the DAC202’s soundstage and its superior imaging schooled the Alpha DAC.

     

    <b>Are We There Yet?</b>

     

    <a href="http://images.computeraudiophile.com/ca/cash-logo-black.png" class="thickbox" rel="cash"><img src="http://images.computeraudiophile.com/ca/cash-logo-black-thumb.jpg" style="padding: 2pt 5pt 2pt 2pt;" align="left" alt="CASH-List"></a>Back to the hovering question. Are we there yet? The combination of a good Windows 7 or Mac server and the Weiss Engineering DAC202 is enough to transport anyone into the world of high end computer audio. The DAC202’s support of all reasonable sample rates via a ubiquitous and low jitter asynchronous FireWire interface, impeccably implemented coarse analog / fine digital volume control, built-in transparency checking, sample rate display, and sound quality to plan this year’s bonus around make it the vehicle that gets anyone “There" and well beyond the capabilities of traditional transports. The DAC202 not only offers all the features required for the foreseeable future it’s the sound quality valedictorian of its class and the latest entrant to the <a href="http://www.computeraudiophile.com/content/Computer-Audiophile-Suggested-Hardware-List">C.A.S.H. List</a>. Now that we’ve answered the “are we there yet" question it’s time to ask, What are you waiting for?

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

    Product Information

    <ul>

    <li>Price - $6,670</li>

    <li>DAC202 Product Page - <a href="http://www.weiss-highend.ch/dac202/index.html">Link</a></li>

    <li>DAC202 Product Brochure - <a href="http://files.computeraudiophile.com/2010/0617/dac202-brochure.pdf">Link</a></li>

    <li>DAC202 Manual - <a href="http://files.computeraudiophile.com/2010/0617/dac202-manual.pdf">Link</a></li>

    </ul>

     

     

    Associated Equipment:

     

    <a href="http://files.computeraudiophile.com/2010/0418/Brochure_Fidelio.pdf">Verity Audio Fidelio loudspeakers</a>, <a href="http://www.mcintoshlabs.com/products/mcintosh-mc275-vacuum-tube-power-amplifier.asp">McIntosh MC275 amplification</a>, <a href="http://www.richardgrayspowercompany.com/products.aspx?type=accessories">Richard Gray's Power Company High Tension Wires</a>, <a href="http://www.berkeleyaudiodesign.com/">Berkeley Audio Design Alpha DAC</a>, <a href="http://www.usbdacs.com/Products/Products.html">Wavelength Audio Proton</a>, <a href="http://www.ayre.com/products_detail.cfm?productid=12">Ayre AX-7e Integrated Amp</a>, <a href="http://www.computeraudiophile.com/content/Computer-Audiophile-Pocket-Server-CAPS">C.A.P.S. server</a>, <a href="http://www.belcantodesign.com/Product_USBlink.html">Bel Canto USB Link</a>, <a href="http://www.halidedesign.com/bridge/">Halide Design Bridge</a>, <a href="http://www.dcsltd.co.uk/product/debussy-dac"><i>d</i>CS Debussy DAC</a>, <a href="http://www.dcsltd.co.uk/product/puccini-u-clock"><i>d</i>CS Puccini U-Clock</a>, <a href="http://www.kimber.com/products/interconnects/digital/usb/bbus/cu/">Kimber USB Cu</a>, <a href="http://www.kimber.com/products/interconnects/digital/usb/bbus/ag/">Kimber USB Ag</a>, <a href="http://www.benchmarkmedia.com/system1/digital-analog-converter/dac1-pre">Benchmark DAC1 PRE</a>, <a href="http://www.kimber.com/products/interconnects/analog/select/singleended/ks1011/">Kimber Select KS1011 Analog Cables</a>, <a href="http://www.kimber.com/products/interconnects/digital/select/ks2020/">Kimber Select KS2020 Digital Cable</a>, <a href="http://www.kimber.com/products/loudspeakercables/monocle/x/">Kimber Monocle X Loudspeaker Cable</a>, <a href="http://usa.asus.com/product.aspx?P_ID=SPZfqXDJvadmFPoh&templete=2">ASUS Xonar HDAV 1.3 Slim</a>, <a href="http://www.apple.com/ipad/">Apple iPad</a>, <a href="http://www.amarraaudio.com/">Sonic Studio's Amarra</a>, <a href="http://www.m2tech.biz/products.html">M2Tech hiFace</a>, <a href="http://www.weiss-highend.ch/dac202/index.html">Weiss Engineering DAC202</a>, <a href="http://www.lynxstudio.com/product_detail.asp?i=13">Lynx Studio AES16 Digital I/O Card</a>.

     

     

     

     

     

     

     

     




    User Feedback

    Recommended Comments



    Barrows,<br />

    Chris could not be the "suppressor." He is receiving the post. The suppression about which I inquired would be a passive one. My point is, I never see too much info. as a bad thing, and want to know any question asked by anyone. if not useful, I hit the delete key.

    Share this comment


    Link to comment
    Share on other sites

    Gordon, if in that context "async" means that the DAC contains the master clock (for the sampling rate) and that the audio source is somehow slaved to that clock, then the Firewire scheme used in the DAC202 is an "async" one. <br />

    An example that it has to be like that is what I have mentioned above, i.e. if the DAC202 is synced to an external clock the computer simply can not be (another) master, except there was an asynchronous sampling rate converter involved, but that is not the case with the DAC202. <br />

    Also, the sampling rates, be it 44.1 and multiples or 48.0 and multiples, can be generated out of a single crystal oscillator with high precision and low jitter. Provided a proper PLL is employed. And that is what is used in the DAC202.<br />

    <br />

    Daniel<br />

    Share this comment


    Link to comment
    Share on other sites

    Daniel,<br />

    <br />

    So you are saying you have two fixed oscillators in the DAC202, that when configured become the basis for the Master Clock going to the DAC chip as well as being feed back into the DICE chip to make the I2S (or other digital audio stream L/R justified, dsp etc)? This would be a requirement for true asynchronous use.<br />

    <br />

    rlodad,<br />

    <br />

    I never go out and test other companies products. This tends to make me stray from my design goals set for any product. It is best for you to contact some dealers and make the call yourself. Also it would be pretty unethical to take the word of any company when they talk about a competing product. What you think they are going to say that theirs is worse? come on...<br />

    <br />

    Metric Halo fans... FYI from their site....<br />

    <br />

    I got a couple of emails this morning and I am sorry to say I was wrong about their implementation it would be very similar to Daniels and is not Asynchronous in nature...<br />

    <br />

    <cite>MIO uses both types of transfers, isochronous and asynchronous pretty much all the time. The isoch transfers are used for audio transport and the async transfers are used for control, metering, and firmware updates. <br />

    <br />

    From their FAQ page.<br />

    <br />

    Thanks<br />

    Gordon

    Share this comment


    Link to comment
    Share on other sites

    <em>"The isoch transfers are used for audio transport..."</em><br />

    <br />

    Could someone explain exactly what this means please?<br />

    <br />

    Mani.

    Share this comment


    Link to comment
    Share on other sites

    Gordon,<br />

    <br />

    I need to start doing this stuff at the end of the day. Clearly, I can't get my point across typing between patients.I wasn't implying that YOU should buy or borrow a DAC202 and/or a BADA to test with and without the Wavelink. I was trying to get an update on when it might be released so that I could buy one to use with the BADA and perhaps Chris might test it with both the DAC202 and the BADA to see if the Lynx and AES/EBU 110 ohm input is the weak link in the "BADA chain."<br />

    <br />

    Back to work for me.

    Share this comment


    Link to comment
    Share on other sites

    <i><br />

    "Metric Halo fans... FYI from their site....<br />

    <br />

    <i><br />

    I got a couple of emails this morning and I am sorry to say I was wrong about their implementation it would be very similar to Daniels and is not Asynchronous in nature...<br />

    </i><br />

    <br />

    Now two highly regarded DACs aren't even async.<br />

    Share this comment


    Link to comment
    Share on other sites

    <br />

    "Could someone explain exactly what this means please?"<br />

    <br />

    Agreed, I think we are deep into semantics here.<br />

    <br />

    Per my understanding, isochronous mode is a 'dedicated bandwidth' feature of 1394 spec (as Daniel explained). Essentially it means that nothing can interfere with the peer to peer communication between the firewire nodes.<br />

    <br />

    <br />

    Re the entire comment "The isoch transfers are used for audio transport and the async transfers are used for control, metering, and firmware updates."<br />

    <br />

    It's been my understanding that the two modes were being used simultaneous. E.g., saying that the isochronous feature is being used to transfer data does not automatically mean that the data on the firewire bus are not also being processed asynchronously.<br />

    <br />

    OTOH, I'm certainly no expert.<br />

    <br />

    as a non-expert, I'm also not sure what, if any, advantage can be claimed for (what Gordon called) True Asynchronous versus the MH/Weiss approach of sending signals to the clock upstream. IOW, how this is a detriment as compared to the "control of flow" commands sent upstream in Async? I can't say. <br />

    <br />

    And now that it appears that (several of) the best sounding world class DACs do not, technically speaking, use Async, I don't really care. :)<br />

    <br />

    What IS interesting to me is that Firewire DACs don't seem to (be as likely to) benefit from fancy cables (as do Async USB), when the opposite would seem to be the case given that USB can claim Async status. ;0<br />

    <br />

    curiouser and curiouser,<br />

    <br />

    clay<br />

    <br />

    <br />

    Share this comment


    Link to comment
    Share on other sites

    "Now two highly regarded DACs aren't even async."<br />

    <br />

    Myth-busters indeed! Firewire (based) DACs don't even need Async to do their magic. ;0<br />

    <br />

    <br />

    <br />

    And kudos to BJ, whose designs kick ass with absolutely NO audiophile pedigree whatsoever! I love it!<br />

    <br />

    EDIT: and also kudos to Daniel, who straddles the line between pro and audiophile gracefully (baring one exception, that of the "twice the price" Minerva vs. the DAC2)<br />

    <br />

    Plus, I was getting tired of typing Asynchronous.<br />

    <br />

    Also, as Gordon has consistently pointed out in the past, it's not the Asynchronous transmission that's so important, rather, it's (Async's support of) the use of fixed oscillators in the DAC being used as the master clock.<br />

    <br />

    clay<br />

    <br />

    PS, As far as I know, MH do NOT need nor use PLLs in the manner Daniel describes, as they employ two oscillators - one for 44.1/88.2/176.4 and another for 48/96/192. I know from personal experience as the first time I tried to play a 96k sample rate file, my ULN-2 would not lock on. Turns out it's "clock" for 48/96k processing needed to be replaced.<br />

    Share this comment


    Link to comment
    Share on other sites

    I can't be the only person who is totally gobsmacked by the fact that these firewire DACs are not truly async after all. I mean, it seems some well-respected posters have had it wrong all this time...<br />

    <br />

    Mani.

    Share this comment


    Link to comment
    Share on other sites

    Mani,<br />

    <br />

    there's a several reasons to be gobsmacked here, but the one you point to is the less important one, in my opinion.<br />

    <br />

    The ramifications of this revelation is that the cachet of Async has next to nothing on which to base it's reputation other than Gordon DACs and now Ayre's QB-9. Nothing, nada, zip! <br />

    <br />

    EDIT: okay, well dCS can be counted, but there gear is so expensive that I don't tend to even consider it.<br />

    <br />

    Said another way, the much extolled virtues of Async transmission were based in part on Firewire devices that are not Async (per Gordon's views on what constitutes Async).<br />

    <br />

    Indeed, apparently NONE of the "well known" contenders (AFAICT) for world class sound in the $5k (+/= $1k) range are actually Asynchronous. Not the BADA, nor any of the Weiss's, nor any of the Metric Halos, not the PM Model Two, nor well, you get the idea. <br />

    <br />

    [Note: no disrespect to Gordon but his Crimson is pricier than this even in base dress and not as much is known about its sound compared to those mentioned above. I"m sure it sounds awesome!]<br />

    <br />

    How's that for 'gobsmacked' material?!<br />

    <br />

    To be fair, and going back to my earlier post, Gordon has said all along that it's not Async that matters, it's the fixed oscillators in the DAC being used as master that's the real deal, and of course, he practically yells that none of us should be worrying about the armchair engineering (as does Chris).<br />

    <br />

    But yeah, more than a few of us (including me) missed the boat.<br />

    <br />

    clay<br />

    <br />

    Share this comment


    Link to comment
    Share on other sites

    <i>"And kudos to BJ, whose designs kick ass with absolutely NO audiophile pedigree whatsoever! I love it!<br />

    </i><br />

    <br />

    I'm not sure BJ is not pedigreed. He just doesn't blow his horn in the high-end circles. He delivers the goods.<br />

    <br />

    He's pretty well versed in digital from what I gather by anything he's written or commented about.<br />

    <br />

    <i><br />

    "EDIT: and also kudos to Daniel, who straddles the line between pro and audiophile gracefully (baring one exception, that of the "twice the price" Minerva vs. the DAC2)"<br />

    </i> <br />

    <br />

    This is the reason I questioned the value of the Weiss products. They may very well sound good, but it seems the MSRP is getting a bit ridiculous for what it is. <br />

    <br />

    EDIT: OMG is it me or did the price jump up since you wrote this review?

    Share this comment


    Link to comment
    Share on other sites

    "The ramifications of this revelation is that the cachet of Async has next to nothing on which to base it's reputation other than Gordon DACs and now Ayre's QB-9. Nothing, nada, zip! "<br />

    <br />

    Do not let your enthusism for the sound of the Metric Halo products blind you to the truth.<br />

    Actually, Async Clocking is used by most good single box CD players, and products such as the PS Audio PerfectWave transport, and PerfectWave DAC with Network Bridge, and the Genesis Digital Lens reclocker.<br />

    The technology of an async interface using fixed frequency oscillators is inherently superior in jitter performance to any other clocking method, as the jitter inherent in a properly implemented async interface is solely the inherent jitter in the clock itself-any other clocking method will introduce more jitter, by definition. The reason for the additional jitter in any other clocking scheme, is that a PLL is used to generate the appropriate clocking frequency, using an oscillator for reference. Once a PLL is added to the clock circuit, one is now dealing with the jitter (at least) of the oscillator itself, plus that of the PLL.<br />

    Now whether or not the additional jitter of a non async solution is an audible problem is something for the listener to decide-but the fact remains that async clocking is a tecnically superior solution.

    Share this comment


    Link to comment
    Share on other sites

    <br />

    "I'm not sure BJ is not pedigreed. He just doesn't blow his horn in the high-end circles. He delivers the goods.<br />

    <br />

    He's pretty well versed in digital from what I gather by anything he's written or commented about."<br />

    <br />

    I agree totally. My point was that BJ delivers the goods without the use of any audiophile approved (rather than pedigreed) methods, e.g. he uses op amps, SMPS, DC-DC converter, etc.<br />

    <br />

    well, if this isn't proof (to me) that Gordon is right about stopping the armchair engineering, I don't know that I'll ever get it.<br />

    <br />

    clay

    Share this comment


    Link to comment
    Share on other sites

    I'm not blinded, imo. :)<br />

    <br />

    Re the point of my comment that you quoted - My intent was to point out, as I did elsewhere in the post, that the cachet that async has here on CA is, in large part, (apparently) due to misconceptions that several well regarded Firewire devices were assumed to be Async. To your comment below, I don't believe that the Async reputation here is built on the devices you mention.<br />

    <br />

    "Actually, Async Clocking is used by most good single box CD players, and products such as the PS Audio PerfectWave transport, and PerfectWave DAC with Network Bridge, and the Genesis Digital Lens reclocker."<br />

    <br />

    None of these products that you mention (are reported to) sound better than (or even as good as) the non Async DACs that I referred to! :)<br />

    <br />

    ...and from my understanding the Asynchronous method in the PWT and the Digital lens is more accurately called a buffer and has nothing to do with using fixed freq oscillators as master clock in the DAC. I bow to your greater wisdom of things PS Audio, but I looked into this last year, and I doubt that it's changed.<br />

    <br />

    Additionally, the reason we have a great site like computer audio is that the CD players you refer to as using async interfaces can be bested, and rather handily, by any number of non-Async DACs.<br />

    <br />

    But you are right, I really did overstate things! :)<br />

    <br />

    <br />

    <br />

    "The technology of an async interface using fixed frequency oscillators is inherently superior in jitter performance to any other clocking method, as the jitter inherent in a properly implemented async interface is solely the inherent jitter in the clock itself-any other clocking method will introduce more jitter, by definition."<br />

    <br />

    Can you (or anyone) state with any certainty that the mechanism in use by Metric Halo is actually inferior to the 'inherently superior' Async interface you point to? Or that it introduces any more jitter?<br />

    <br />

    I don't believe that a PLL is in use for Internal clocking mode, but I can check.<br />

    <br />

    As far as I can tell, MH's use of fixed frequency oscillators and use of async communication upstream to 'control' the speed at which data is received by the clock is only different semantically from Gordon's definition of Async. <br />

    <br />

    Is there a practical difference that has an impact on the sound? If so, I don't get it yet.<br />

    <br />

    I'd say the proof is in the pudding. If we look at the evidence (of "true" Async DACs as compared to the MH) I'd say that we don't. Indeed using your examples, and even that of the Ayre QB-9, in my opinion, the evidence favors non Async (if indeed the MH box is not Async), any theoretical advantage notwithstanding. :)<br />

    <br />

    GOrdon's top piece uses a 'take no prisoners' analog approach and it starts out at almost twice the price of the LIO-8 before you start thinking about all those oh-so-tempting options (I've looked at these too!). For that reason, it's hard to do a comparison on a cost basis with the top non-Async DACs.<br />

    <br />

    BTW, I would (still) tend to agree with you that Async SEEMS like it would be theoretically superior - I'm not really arguing that, only that IF the MH box actually significantly differs from Async, then frankly, my opinion will change - and the theoretical advantage will be just that - almost entirely theoretical. :)<br />

    <br />

    In fact, the reported sound of the Weiss DAC would seem to call in question, the significance of any perceived inherent disadvantage of using PLLs.<br />

    <br />

    If my post comes across as combative, that's not my intent. I'm really enjoying a conversation with people whose opinion I respect a lot - thanks for your post.<br />

    <br />

    all the best,<br />

    Clay<br />

    <br />

    <br />

    Share this comment


    Link to comment
    Share on other sites

    Thanks for the informative article and your enthusiastic opinion. I've enjoyed the spirited comments as well.

    Share this comment


    Link to comment
    Share on other sites

    Where else can you find three of the biggest names in computer audio debating the finer points of a third-party review of an audio product? This is friggin' awesome! <br />

    <br />

    Charles, Daniel, Gordon -- please, for the love all that is good and righteous -- keep it coming! <br />

    <br />

    Sweet!!!<br />

    <br />

    Share this comment


    Link to comment
    Share on other sites

    Hey Clay what about this:http://www.centrance.com/products/dacport/<br />

    <br />

    <i>Jitter Management - Debunking the Asynchronous Myth<br />

    Some manufacturers may lead you to believe that Asynchronous USB transfers are superior to Adaptive USB transfers. This no more true than saying that you "must" hold the fork in your left hand. If you know what you are doing, you will feed yourself with either hand.<br />

    <br />

    <br />

    <i>The USB argument comes down to jitter management and goes as follows: In Asynchronous mode the device is the clock master. In Adaptive mode, the computer is the clock master. Either way works fine, if correct design principles are followed. Here is the tricky part that often gets omitted: No matter which side is the source of the clock (PC or DAC), the two devices are still connected by the USB cable and the digital data on that USB cable is always irregular because the computer is involved. Computers do many things at once and end up sending data over USB in irregular intervals, no matter who is the clock master on the bus. This irregularity causes jitter. So, there is no jitter-free solution, just like there is no dust-free house. Irregularity always creeps in and needs to be actively managed.<br />

    <br />

    <br />

    <br />

    <i>Here is where the Asynchronous vs. Adaptive argument breaks down: In either of the two clocking schemes, jitter is present during transmission. It's inevitable and also ok, if it is properly cleaned up prior to the D/A conversion, where it matters most. Neither clocking scheme is superior and both are capable of performing well if you know how to reassemble the bits prior to the DAC. Now, how do you actualy do that? There are many ways, the oldest and simplest of which is buffering. Irregular data comes in, regular data goes out. The most important part is to make sure that samples leaving the buffer on the way to the DAC are clocked accurately. DACport employs JitterGuard™, a proprietary two-stage clock management system that does just that - cleans up the jitter on the USB bus so that samples are virtually jitter-free at the D/A conversion point <br />

    <br />

    oh and don't forget dCS....they are truly async aren't they.<br />

    Have a Dacport for use in the office. Nice kit.

    Share this comment


    Link to comment
    Share on other sites

    Actually, BJ seems well versed in all aspects of design. Analog, digital, power supplies. And there seems to be no pretense at all with him. No ego trip. <br />

    <br />

    To me it seems that Async transfer is more of an advantage with USB than firewire. Maybe because the USB interface works differently and the clocking etc is different since it wasn't originally designed for audio video like firewire.<br />

    <br />

    BTW, the price of the DAC202 was increased. I googled the article and the review originally had the DAC202 priced at $6440. So the price has gone up by $230. Is that because our discussion is drawing attention to the DAC202, thereby increasing the value of the product? It's a becoming a hot commodity!

    Share this comment


    Link to comment
    Share on other sites

    >> Jitter Management - Debunking the Asynchronous Myth <<<br />

    <br />

    This is just silly. Of course, here's a manufacturer who has a dog in the fight. All of his products are adaptive (although I've heard rumors that he's working hard on asynchronous technology). So of course he's going to defend his technology. (At least until he get async working.)<br />

    <br />

    And the perceptive reader will note that I also have a dog in the fight. But these claims are just silly. I won't even bother to rebut them as there are probably a couple of dozen posters here that could just as easily.<br />

    <br />

    That said, jitter is just one of hundreds of parameters that affect the sound of a digital product. But since it doesn't cost any more to do it right and use async to get the lowest jitter possible, that is what we choose to do. And of course we also address all of the other factors that we can (given the price point and given the fact that we refuse to build our equipment in Chinese prison camps).<br />

    <br />

    And the wonderful thing is that you, the consumer, get to buy whatever equipment you want for whatever reason you want. Maybe because you like the looks. Maybe because your dealer will give you a discount. Maybe you like the sound. Maybe you like the feature set. Maybe, maybe, maybe....<br />

    <br />

    Have fun and happy listening!

    Share this comment


    Link to comment
    Share on other sites

    <i><br />

    "This no more true than saying that you "must" hold the fork in your left hand. If you know what you are doing, you will feed yourself with either hand.<br />

    </i><br />

    I don't know if I'd believe what centrance says. Seems like propaganda. And what the heck does eating with a fork have to do with jitter?<br />

    <br />

    The problem with USB adaptive mode appears to be that the DAC clock has to follow the computer clock so you can't use a highly stable clock at the DAC. It has to be continually readjusted and that causes jitter.<br />

    <i><br />

    "No matter which side is the source of the clock (PC or DAC), the two devices are still connected by the USB cable and the digital data on that USB cable is always irregular because the computer is involved."<br />

    </i><br />

    <br />

    So get out of the business of writing code for USB receivers then. <br />

    <br />

    <i><br />

    "Jitterguard"<br />

    </i> <br />

    <br />

    I hate names like "Jitterguard" or "ultralock" some companies give to their processes. To me it's a sign that they don't know what they're talking about so they need all these trademarked buzz words to create marketing hype.

    Share this comment


    Link to comment
    Share on other sites

    to respond:<br />

    <br />

    "None of these products that you mention (are reported to) sound better than (or even as good as) the non Async DACs that I referred to! :)"<br />

    <br />

    The above is subjective analysis, as stated in my post above, my only concern was to state that from a technical perspective, asyncronous clocking with fixed frequency oscillators will result in the lowest possible jitter, as the jitter is essentially just the inherent jitter of the clock itself and nothing more. As noted, the listener has to decide which sounds better, but-I have participated in listening tests which compared using an asyncronous clock to using using a PLL generated clock with all other parameters staying as close to the same as possible, and there was no contest-the asyncronous clock was obviously better sounding.<br />

    <br />

    "...and from my understanding the Asynchronous method in the PWT and the Digital lens is more accurately called a buffer and has nothing to do with using fixed freq oscillators as master clock in the DAC. I bow to your greater wisdom of things PS Audio, but I looked into this last year, and I doubt that it's changed."<br />

    <br />

    Both The PerfectWave transport and the PerfectWave DAC (when operating as a network player with the Network Bridge installed) are asycronous, with two fixed frequency oscillators (one for 44.1 base, and one for 48 base), clocking the data out of the memory, with no reference to any incoming timing. In the case of the PWT and PWD used together, the master clock ends up being in the transport, but they are connected by I2S (not SPDIF), so the transport clock connects to the DAC directly (no PLL). When the PWD is used as a network player, it is asyncronous also, fixed frequency oscillators control the timing out of the memory, direct I2S to the DAC chip, with no reference to any other clocks. <br />

    <br />

    "Additionally, the reason we have a great site like computer audio is that the CD players you refer to as using async interfaces can be bested, and rather handily, by any number of non-Async DACs."<br />

    <br />

    In my experience, this is actually not true, and is one of the fallacies of computer audio. A really good single box CD player will beat most simple computer based systems, at least to my ears. In any case, this is off my intended topic: that asyncronous clocking is technically superior. <br />

    <br />

    RE: Metric Halo, they do not seem to be very forthcoming in describing exactly how their products work, this is certainly their option, do you know how they work in regard to generating the clock? I am just curious.<br />

    As Charles H. mentioned, everything matters, and jitter is just one parameter. A DAC might sound good even with higher jitter if everything else is well sorted-my only point is that this same DAC will sound even better if its jitter is lowered (while keeping everything else well sorted).<br />

    <br />

    Centrance: yup, looks like they are using some marketing terms (not that there is anything wrong with that). Sounds like they are using a dual PLL, similar to what Weiss does, to "clean up" the jitter. This is what might be referred to as a "band aid" approach-it might work (and it might have negative side effects, as I believe asyncronous sample rate converters do)-I have to agree with Gordon Rankin's approach here, much better to not get wounded in the first place, then no need for band aids.<br />

    <br />

    All of the asyncronous approaches take advantage of a memory buffer, the data goes in the buffer, and is clocked out by the appropriate fixed frequency clock. The key is keeping the buffer from overunning or underunning-my understanding is that Wavelength Audio's Streamlength code does this by managing the data sent over USB, slowing it down, or speeding it up as necessary so that no samples are dropped, and the clock at the output of the buffer can just run at the correct speed. The PS Audio products use relatively large amounts of memory, and use code to keep the memory from overuns or underuns. Adaptive USB (and Firewire using a PLL) systems instead change the clock frequency itself (introducing jitter) to keep the buffer from overunning or underunning. The asyncronous approach is a simple (although apparently difficult to implement) and elegant solution to virtually eliminating jitter as an issue.<br />

    <br />

    What's the best sounding DAC, well that is another question! But my experience leads me to believe that low jitter is important to the best sound-just like digital filters, power supplies, DAC converters, I to V and analog output stages, passive parts quality, etc, and in no particular order.<br />

    Share this comment


    Link to comment
    Share on other sites

    Totally agree with Barrows.<br />

    <br />

    I would add that you are constantly polluting threads here with MH products. The ultimate argument being 'it just sounds better'.<br />

    <br />

    That would be very nice to try and pollute only one thread out of two :D<br />

    <br />

    Although the rest of my comment is not totally on-topic also, I can say that the Int202 Jitter handling architecture has absolutely no effect in my system (against Jitter prone interface). So yes, there is more than Jitter in life :)<br />

    <br />

    Elp

    Share this comment


    Link to comment
    Share on other sites

    Charles I have always respected your and your products particularly your no BS approach to pricing and marketing of your products.<br />

    <br />

    I am not from mainland China but but your comments of "Chinese prison camp" shows your ignorance and insensitivity.<br />

    <br />

    Share this comment


    Link to comment
    Share on other sites

    Barrows,<br />

    <br />

    "The above is subjective analysis,"<br />

    <br />

    Agreed, but I think there's a lot more support here for my position than yours.<br />

    <br />

    "... as stated in my post above, my only concern was to state that from a technical perspective, asyncronous clocking with fixed frequency oscillators will result in the lowest possible jitter, as the jitter is essentially just the inherent jitter of the clock itself and nothing more."<br />

    <br />

    As I stated I did not disagree with the comments about the theoretical advantage. My point was, and remains, that a large part of the evidence presented on CA (that convinced ME at least) that this theoretical advantage actually means anything in the real world was based on the belief that great sounding Firewire DACs such as the Weiss and Metric Halo products were/are asynchronous "in nature". If that is indeed not true (for the MH boxes that I have personal experience with), then MY OPINION as to the need for Async changes. <br />

    <br />

    I can sympathize with those who might think that my opinion (on Async) 'flapping with the breeze' here, but...keep in mind, my personal experience (on computer interfaces) is predominantly with Metric Halo boxes, and I was using the MH boxes as the evidence that allowed my full support for, and belief that, Async transmission WAS important. <br />

    <br />

    I'll also repeat - we've all learned that Async transmission is NOT the most important aspect (per Gordon and others) - it's the use of fixed freq oscillators (that are not varying to track some upstream clock) that offer the lowest jitter. <br />

    <br />

    <br />

    I said:<br />

    "...and from my understanding the Asynchronous method in the PWT and the Digital lens is more accurately called a buffer and has nothing to do with using fixed freq oscillators as master clock in the DAC. I bow to your greater wisdom of things PS Audio, but I looked into this last year, and I doubt that it's changed."<br />

    <br />

    Barrows, perhaps you missed my point here. I was referring ONLY to the (gratuitous, imho) use of the word "Asynchronous" as a description of the nature of the PWT and Digital Lens products themselves (Paul was using one year ago to describe their buffering scheme), and not the PWD used alone or with the PWT/Network bridge. I only made this comment due to your inclusion of the PWT and Digital Lens in your comment about the use of Async<br />

    <br />

    <br />

    "RE: Metric Halo, they do not seem to be very forthcoming in describing exactly how their products work, this is certainly their option, do you know how they work in regard to generating the clock? I am just curious."<br />

    <br />

    I have an email into BJ now.<br />

    <br />

    I'll share the results.<br />

    <br />

    "The asyncronous approach is a simple (although apparently difficult to implement) and elegant solution to virtually eliminating jitter as an issue."<br />

    <br />

    The armchair engineer in me loves the idea of Async communication!<br />

    <br />

    <br />

    "What's the best sounding DAC, well that is another question! But my experience leads me to believe that low jitter is important to the best sound-just like digital filters, power supplies, DAC converters, I to V and analog output stages, passive parts quality, etc, and in no particular order."<br />

    <br />

    agreed that the entire system is what's important. <br />

    <br />

    as for what is the best sounding DACs, I can only point to consensus beliefs as I don't have the time or opportunity or even interest in comparing all the top contenders. <br />

    <br />

    Re the consensus, I will restate that we now have a lot less evidence that Async transmission is needed for world class sound if indeed none (or very few) of the current contenders actually employ Async as defined by Gordon and your self. :)<br />

    <br />

    <br />

    all the best,<br />

    Clay<br />

    Share this comment


    Link to comment
    Share on other sites

    <br />

    <br />

    "I would add that you are constantly polluting threads here with MH products."<br />

    <br />

    I'll be the 'judge' of that! ;0<br />

    <br />

    "That would be very nice to try and pollute only one thread out of two :D"<br />

    <br />

    nice!<br />

    <br />

    hope all is well, when this thread winds down, you'll hear a lot less from me. <br />

    <br />

    clay

    Share this comment


    Link to comment
    Share on other sites




    Guest
    This is now closed for further comments




×
×
  • Create New...