• Berkeley Audio Design Alpha DAC Review

    Over the last few months I've talked more about the Berkeley Audio Design Alpha DAC than perhaps any other product. The Alpha DAC appeared on the CASH List from the very beginning and has since been the subject of several reader discussions here on Computer Audiophile. Under normal circumstances I would be concerned as frequently discussed products often don't live up to the hype they've generated. This however is not a normal circumstance. The Berkeley Audio Design Alpha DAC is seriously out of this world. At $5k it's a relative bargain in high-end audio terms and there is nothing like it available today.

     

     

    Berkeley Audio Design

    Berkeley Audio Design was founded by René Jaeger, Michael “Pflash” Pflaumer, and Michael Ritter. All three gentlemen are well known for their previous work at Pacific Microsonics. Pflash Pflaumer is the co-inventor of the HDCD process, in addition to writing all the digital algorithms used in the Pacific Microsonics Model Two. The Model Two is commonly thought to be the best ADC / DAC produced in recent memory. Unfortunately there were only 150 Model Twos produced and they have long since been out of production. This past weekend on my trip to Seattle and the San Francisco bay area I had a chance to meet with all three founders of Berkeley Audio Design. I talked to René Jaeger over breakfast in Seattle, before heading to the Bay Area. Then I spoke with Michael and Pflash during lunch at Eccolo in Berkeley, CA. All three Berkeley Audio Design founders are first class guys who were very eager to discuss the Alpha DAC and computer based audio in general. After discussing some technical details about the Alpha DAC with Pflash I realized that he has likely forgotten more information than I'll accumulate over the course of my entire life.


     

     


    Alpha DAC Front


    Berkeley Audio Design Alpha DAC
    click to enlarge


     

     

    Alpha DAC Features

    As I said in my opening paragraph, the Alpha DAC is seriously out of this world. Sonically I've never heard better. In addition to sound quality the Alpha DAC has some fabulous features that are indispensable. The single most important feature of this DAC is its ability to decode HDCD and illuminate an HDCD indicator when HDCD encoded content is detected. One constant in the world of computer based audio is the worry that looms over listeners wondering if their computers are outputting bit perfect data to their DACs. The HDCD indicator on the Alpha DAC is not foolproof, but there is a 99.99% chance that a computer is outputting bit perfect data if the HDCD indicator is illuminated upon playback of an HDCD encoded track. This is because the HDCD flag is located on the 16th and 24th bit of 16/44.1 and 24/44.1-192 content respectively. As I noted in a response to a reader in September, "If the HDCD indicator illuminates on the Alpha DAC, the data is uncorrupted. Theoretically, it is possible to alter HDCD data using specialized software while not touching the LSB, but all of the typical mechanisms that might alter data in a computer environment such as level shifting, dither, SRC’s, etc. will definitely affect the LSB. And, if the LSB is altered the HDCD code is lost. So, as a practical tool, presence of the HDCD light indicates no alteration of the data file."

    The Alpha DAC's front panel display indicates the current sample rate or volume level depending on the listeners selection. This is an easy way for listeners to verify that data coming out of their computer has the correct sample rate. Avoiding software sample rate conversion (SRC) is a high priority for many listeners. The Alpha DAC display removes almost all ambiguity from the computer playback process. If you're playing a 24/176.4 track from Reference Recordings and the Alpha DAC is not indicating the presence of HDCD and the sample rate is not indicating 176.4, then you know you have some configuration issues. Compare this to a user without the Alpha DAC who thinks his computer is performing at its highest level even though the sound is not quite right. I think we'd all like to know when the sample rate is wrong and remedy the situation ASAP so we can get back to listening unaltered music. We've all had issues with our audio systems, traditional or computer based, and we've all jumped for joy when inserting a component that solves the issue or when removing a component causing the trouble. I've said to myself more than once, "how could I have listened like that for weeks without knowing something was wrong?" The Alpha DAC gets us one step closer to identifying sources of imperfect sound. In my conversation with Pflash a couple days ago he stated that the display of the Alpha DAC is updated at the very beginning of a track. Thus, the Alpha DAC reads a 176.4 track and updates the display instantly upon playback. Following the sample rate update the display totally "disengages" (my word, not Pflash's) from the rest of the DAC. This is among many other design elements that contribute the Alpha DAC's stellar sound quality.

    Possibly the most underrated part of the Alpha DAC is its ability to bypass a pre amp and connect directly to a power amp(s). The Alpha DAC has its own digital volume control that is as well implemented as I've ever heard. Trust me, I'd have a pre amp in my system in a heartbeat if I thought the Alpha's volume control degraded the sound in any way. As a test I connected the Alpha DAC to a pre amp and was so disappointed I reverted to the pre amp-less configuration in under two tracks. I spoke to Berkeley Audio Design's Michael Ritter about the digital volume control and he indicated that even the best pre amps in the industry can degrade the sound coming from the Alpha DAC. The digital volume control and analog output stage in the Alpha DAC are very solid. That said, I do know people using pre amps with their Alpha DACs. Some people must use a pre amp for the analog inputs and others just like the sound of their system using a pre amp. When the Alpha DAC is used with a pre amp the optimal volume setting on the DAC is 54 dB. The main point to keep in mind is the Alpha DAC offers listeners options. The Alpha DAC has traditional DAC inputs and outputs. Both single ended RCA and balanced XLR connections are available for the analog output. The usable inputs are limited to AES/EBU, S/PDIF, and Toslink.

    Shortly after the Alpha DAC arrived I noticed a barely audible hum coming from the DAC. I immediately thought something was wrong so I contacted Michael Ritter seeking an answer. What Michael told me only solidified my belief that sound quality was the foremost concern of the Berkeley Audio team. He explained that the Alpha DAC has two totally separate power supplies for digital and analog, and two power transformers. The dual bobbin transformers used in the Alpha have very high isolation between the primary and secondary windings that provides maximum immunity from line noise. One side effect of this high isolation is a narrow area of magnetic field that causes the bottom of the DAC to hum a little bit. Berkeley Audio Design could have opted for an absolutely silent solution at the cost of sonic degradation. Listeners will be happy to know the hum is inaudible when listening to music even at the lowest volume the Alpha DAC is capable of producing, 0.1 dB.


     

     


    Alpha DAC Rear


    Berkeley Audio Design Alpha DAC
    click to enlarge


     

     

    The Sound

    During the Alpha DAC review I used two different computer sources. One source was my Mac Pro running OS X and a Lynx AES16e PCI-Express digital I/O card outputting AES/EBU to the Alpha DAC. The other source was my very inexpensive Dell Inspiron 530 running Windows XP and the Lynx AES16 PCI digital I/O card. I played back WAV and AIFF files with sample rates from 44.1 to 192 kHz. The software applications used were iTunes 8 (OS X), Amarra (OS X), Foobar2000 (XP), and MediaMonkey (XP).

    The single most recognizable and talked about characteristic of the Alpha DAC is its soundstage. I describe the soundstage as expansive, transparent, and three dimensional. The soundstage produced from the Alpha DAC is unlike anything else. It is perhaps what makes the music reproduced through the Alpha DAC sound live instead of recorded. Listening to Crown Imperial from the Dallas Wind Symphony at 24/176.4 was truly an awesome experience. The music appeared to float in front of my listening chair and reach all the way to the back wall of my listening room at times. The transparency of the Alpha DAC is unparalleled by any DAC I've heard in recent memory. This includes some very highly regarded DACs at the 2008 Rocky Mountain Audiofest. The Alpha DAC's ability to remain extremely resolving at very high and low frequencies is astounding. Very complex orchestral material is no challenge for the Alpha DAC. Each instrument has clear separation from the top to the bottom of the spectrum. Since the Alpha DAC / Lynx combination supports everything up to 24/192, I listened to a plethora of high resolution albums during the review period. In fact I must have played the Reference Recordings HRx material at 24/176.4 more times than I can count. In order to truly give the Alpha DAC a workout and push the DAC to its limits, high resolution material is a must. Don't get me wrong the Alpha DAC handles 16/44.1 material like no other, but why listen to low resolution when you don't have to? Transients through the Alpha DAC were highly dependent on the source material and components. This is another feather in the Alpha DAC's cap as the DAC does not produce sound that it isn't presented. For example, using iTunes and the AES16e card on my Mac appeared to produce what I call rolled transients. The sound didn't quite have the edge present in the original recording, but this was not a fault of the Alpha DAC. Switching over to my XP machine with a Lynx AES16 and MediaMonkey the transients were clearly present with authority. Listening to Fanfare for the Common Man at 24/88.2 (HDCD) was an eye-opener. The attack of the drums was intense at high volumes. I almost felt like the "blown-away guy" photographed by Steve Steigman for the popular Maxell advertisements of the late 1970s and 1980s. I did listen to each interface on the Alpha DAC and settled on the AES/EBU as my favorite. I must admit this was not an apples-to-apples comparison because I used the Lynx card as my digital I/O for the AES/EBU output and I used the Mac's built-in TosLink output as another digital I/O. Hardly a fair comparison, but I used available interfaces that many readers will consider when using the Alpha DAC or the DAC of their choice. Overall the sound of reproduced music through the Berkeley Audio Design Alpha DAC was absolutely stunning. I have very good reason to include the Alpha DAC on the CASH List without hesitation.

    My review of the Alpha DAC would not be complete with comparing it to the competition. I consider the two premiere DACs at the moment to be the Alpha DAC and the Weiss Minerva. (When the full Sonic Studio Amarra software/hardware package is released I expect it to be very compelling as well). I came to this conclusion through my own listening tests, as I did have both units here at the same time, and based on the frequent communication I have with Computer Audiophile readers. Even at Rocky Mountain Audiofest I ran into a very nice CA reader who was inquiring about an Alpha DAC versus the Minerva. It's a very hot topic to say the least. First and foremost both DACs are capable of incredible sound, as evidenced by my reviews of each DAC. Provided you have the proper interface you won't be disappointed by either DAC. Deciding which DAC to chose is entirely personal and depends greatly on the listener's taste, available interfaces, and feature requirements. Both DACs are right around $5,000. In my opinion the major sonic difference between the two is soundstage. I described the Alpha DAC's characteristics in detail above so I'll get right to the Minerva. The Minerva has a much more focussed 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. Next those considering each DAC should consider the interface required. If you need FireWire the choice is rather easy. The Minerva has FireWire 400 in addition to other interfaces whereas the Alpha DAC has the three aforementioned traditional interfaces. The Minerva also has digital outputs should you need it as a FireWire to AES interface. To further narrow down the choice between DACs the listener should consider the features of each DAC. The Alpha DAC is very strong in this department with the built-in volume control, remote control, ability to bypass a pre amp, HDCD decoding and indicator of bit perfect audio, and the sample rate display on the front panel. In addition to these considerations I strongly recommend potential purchasers contact a local dealer to discuss their needs. Berkeley Audio Design and Weiss have lists of dealers available on their websites.

     

     


    Alpha DAC


    Berkeley Audio Design Alpha DAC
    click to enlarge


     

     



    Conclusion

    There is a very valid reason why Berkeley Audio Design is selling Alpha DACs as fast as it can produce them. The Alpha DAC is simply stunning. The Berkeley Audio Design team is one of the most respected in the industry. They have succeeded in their goal of making a very high level of fidelity available to music lovers everywhere. That is unless the music lover is in a ROHS required country, but that's a story for a different day. At $5,000 the Alpha DAC is a high-end audio bargain. This level of quality and features could honestly sell for twice or three times the price. Every Alpha DAC owner and audiophile I've talked to who has heard the DAC has been very impressed. In a recent DAC shootout for the Bay Area Audio Society the Berkeley Audio Design Alpha DAC took first place hands down. I would not be surprised to see the Alpha DAC ascend to the top of many lists and receive much deserved accolades in the weeks and months ahead. Whether I'm using Mac OS X or Microsoft Windows the Alpha DAC from Berkeley Audio Design is my reference DAC for the foreseeable future.



     

     

    Manufacturer: Berkeley Audio Design, LLC
    Phone: 510-277-0512
    Email: info@berkeleyaudiodesign.com
    Alpha DAC Price: $5,000
    Dealer List



     

     

    Associated Equipment: Mac Pro, Lynx AES16e card, Kimber USB cable, Cambridge Audio DacMagic, Weiss Engineering Minerva, Benchmark DAC1 PRE, Kimber Select cable, Avalon Acoustics speakers, Focal Electra Be series speakers, McIntosh tube amplification, Virtual Dynamics power cables, Richard Gray's Power Company cables, Bel Canto USB Link.

     

     
     

     




    Alpha DAC Details from berkeleyaudiodesign.com:




    PRODUCT HIGHLIGHTS
    •Highest audio quality DAC
    •All distortion products below one part per million
    •Unequalled interpolation technology up-samples 44.1kHz CD’s to almost 176.4kHz quality and
    provides superb fidelity at all sampling rates from 32kHz to 192kHz
    •IR remote control of all functions including volume and balance allows direct connection to power amplifiers
    •Advanced input signal jitter rejection
    BADA encrypted input allows future support of HDMI and other DRM formats
    •Designed by Pacific Microsonics Model One and Two design team

     

    CONTROLS & INDICATORS
    •Input selects AES, SPDIF, Toslink or BADA inputs
    •Lock LED indicates input signal lock
    •HDCD LED indicates HDCD code detected
    •Phase sets absolute phase
    •Invert LED indicates absolute phase inverted
    •3 digit LED display of Stereo/L/R attenuation, Sampling Rate and Filter type
    •± controls set attenuation level and select Filter type
    •Mode selects Stereo/L/R attenuation, Sampling Rate and Filter type display modes
    •Dim selects multiple display brightness levels

     

    SPECIFICATIONS
    •Input sampling rate: 32kHz to 192kHz
    •Input word length: 24-bit
    •Two channel analog stereo outputs: XLR balanced and RCA unbalanced
    •Digital Inputs: AES - Single XLR 110?, SPDIF - BNC 75?, Toslink – Optical, BADA encrypted - RJ-45
    •HDCD decoding detects 16-bit flag at 44.1kHz or 24-bit flag at all sampling rates
    •Multiple digital filter options
    •Multiple units can be combined for multi-channel/surround reproduction
    •Balanced analog output level: +18dBu maximum, +12dBu or lower recommended
    •Unbalanced analog output level: 3.25Vrms maximum, 2Vrms or lower recommended
    •Digital attenuation and balance control: 0.1dB/step with .05dB/step trim, 60dB range
    •Frequency response at ? 88.2kHz sampling rates: ± 0.1dB from < 0.1Hz to 35 kHz, - 3dB at 59kHz for 176.4kHz and 192kHz sampling rates
    •Distortion at recommended levels: all products ? -120dBFS
    •THD+N at maximum level: < -110dBFS
    •Setup stored in non-volatile flash ROM
    •Firmware field upgradeable through signal inputs
    •Enclosure dimensions: 1.75”H X 16.5”W x 10.4”D, 19” rack mount option
    •Mains voltage: 100/120/240VAC, 50/60Hz
    •Power consumption: 25W

     

     

     
    Comments 117 Comments
    1. daglesj's Avatar
      daglesj -
      Very good thanks.<br />
      <br />
      One point though..at $5000 its no bargain, relative or not. <br />
      <br />
      $500 or less...maybe.
    1. Elprior's Avatar
      Elprior -
      That seems to be a very nice product.<br />
      <br />
      dCS does all that too, and even more : digital outputs, word sync I/O, dsd, ...<br />
      And quite interestingly, the power supply is also having a little hum, when you come close.<br />
      Ever done a true comparison (I mean outside a show) ?<br />
      <br />
      Elp.
    1. limesinferior's Avatar
      limesinferior -
      Thank you Chris for this very interesting review of Berkeley Alpha.<br />
      <br />
      I have to admit it would be interesting to read your review of a much cheaper component that is making some hype in computer audio community, I got in mind ASUS Xonar Essence STX sound card. <br />
      <br />
      http://en.expreview.com/2008/10/20/asus-xonar-essence-stx-nice-sound-card-with-snr-up-to-124db.html/2<br />
      <br />
      I am looking forward to reading your opinion on it, especially when using it directly in connection with some good headphones like Grado.<br />
      <br />
      thank you,<br />
      limesinferior
    1. audiozorro's Avatar
      audiozorro -
      It would be preferable to start a new thread than to hijack the Berkeley Alpha DAC review for a sound card.<br />
      <br />
      My personal opinion is that the ASUS is a lot of hype. Not that it isn’t a good soundcard but there seems to be a ton of postings on the Internet, but no one has heard it or has posted any listening evaluations.<br />
      <br />
      ASUS makes several other decent soundcards but I wouldn’t know what makes this one so much better. In addition there are several other good soundcards including the Lynx L22. In general, people have found internal soundcards to be a cheap and decent alternative to doing what CA is advocating here. In fact, I would say that the audio out from my MacBook Pro connected directly to my amplifier is pretty darn good.<br />
      <br />
      Anyway the Berkeley Alpha DAC is a proven winner with substantive reviews and evaluations and that’s no hype.<br />
    1. jeroen020's Avatar
      jeroen020 -
      Hi Elprior,<br />
      <br />
      Some questions concerning your dCS, I hope you're willing to share.<br />
      <br />
      Are you using the Delius or Elgar Plus ?<br />
      <br />
      Which interface are you using ? And is that able to play 192 khz.<br />
      <br />
      And last, do you upsample, and if so, what is the impact of it, and did you try softwarebased upsampling ?<br />
      <br />
      Looking forward to your reply.<br />
      <br />
      Jeroen
    1. StephanLJ's Avatar
      StephanLJ -
      Hi Chris<br />
      <br />
      Thank you for the fabulous review. You are 100 % on time and target. dCS I had, I like the alpha Dac better ... and your site anyway. Keep up the great work. Thank you again for the educational results your site has to offer.<br />
      <br />
      Greatings Stephan
    1. limesinferior's Avatar
      limesinferior -
      I found the review of Berkeley's Audio Design Alpha DAC very useful, especially the part which compares pros of alpha and minerva. It was not my intention to "hijack" ... anything.<br />
      <br />
    1. Elprior's Avatar
      Elprior -
      Hi Jeroen,<br />
      <br />
      I'm certainly willing to share .<br />
      <br />
      I'm using the Delius along with the Purcell (upsampler).<br />
      Everything is being played at 192khz (or 176khz depending on my state of mind), although there is an annoying limitation here.<br />
      The Delius handles 192khz through dual aes or dsd.<br />
      The Purcell can only handle 96khz as an input (whatever the input may be).<br />
      <br />
      So the upsampling so far is handled by the Purcell.<br />
      The benefits I can hear are numerous :<br />
      1) There is much more air between the performers, while everything remains connected.<br />
      2) The decays are much smoother.<br />
      3) The sound is coming to you (wider soundstage).<br />
      <br />
      Now, I can think of drawbacks too :<br />
      1) The pace of the music is somehow quieter.<br />
      That is a conclusion I have come to when you are using components that tends to the analogue feeling. You are having a much smoother sound, much more information, air, ... but the rythm is a bit slower.<br />
      2) Can't use the Purcell as long as I need a 192khz capable input (as stated above).<br />
      <br />
      As for using my computer as a drive, I'm still stuck with my loosy components, that ain't compatible with ASIO.<br />
      So I'm being SRC everywhere in my windows xp based system. I'm willing to give the Lynx card a try, but a forum here is showing someone that can play easily through the dCS, and another one who can't (PLL issue it seems).<br />
      Hopefully, I'm about to test the Mac solution with a friend of mine.<br />
      I'll let you know where the thing goes with it.<br />
      <br />
      Elp.<br />
    1. Young Skywalker's Avatar
      Young Skywalker -
      Hi Chris,<br />
      <br />
      Thanks for the review although I didn't really learn anything I didn't already know from my own audition, albeit brief, of the Alpha DAC in a friend's system.<br />
      <br />
      I wonder if you compared the Minerva and Alpha DACs using a digital interface that is common to both, i.e, the AES output from the Lynx AES16 PCI card in your PC (or Lynx AES16e in the case of your Mac)? If not how do you know that the sonic differences you noted were not, at least in part, attributed to the Lynx AES versus Firewire interfaces rather than the DAC chip, filtering or analog output stage?<br />
      <br />
      Best Regards,<br />
      Aaron
    1. Purite Audio's Avatar
      Purite Audio -
      It is a good piece of writing, but like any review it can only tell you so much, it is important to hear every component in your own system, and if possible compare to the other 'possibles' keep up the good work Chris.
    1. jeroen020's Avatar
      jeroen020 -
      Thanks a lot Elp.<br />
      <br />
      So far I didn't buy an dCS, but it is on my shortlist. <br />
      <br />
      When you did some testing with your friends Mac it would be great to hear about it.<br />
      <br />
      Jeroen
    1. shaq's Avatar
      shaq -
      Great to hear about this fine sounding equipment.<br />
      <br />
      First of all, technically- I known I don't need a preamp to play from my computer server when I use the DAC. Can I plug my Tom Evans Phono Preamp into the Berkeley and still hear great vinyl sound?<br />
      <br />
      And what sound difference am I likely the experience when I eliminate the BAT tubes in the chain? My amp is solid state.<br />
      <br />
      Thank you<br />
    1. Purite Audio's Avatar
      Purite Audio -
      The signal from your phono is analogue.
    1. The Computer Audiophile's Avatar
      The Computer Audiophile -
      Coops is exactly right. Your phono signal is analog and the Alpha DAC does not have an analog input.<br />
      <br />
      If you remove the BAT tubes you will remove the sonic signature of the BAT tubes. All equipment has a sonic signature and acts like a filter down stream. Removing the BAT tubes will remove the filter.
    1. shaq's Avatar
      shaq -
      So, in order to incorporate a Berkeley and keep my phono- I have to utilize a preamp to connect my phono pre to. Thus I will inevitably run the DAC into the preamp as well- all to go to the amp?<br />
      <br />
      I cannot run the Berkeley directly into the amp without giving up phono.<br />
      <br />
      Am I misunderstanding something here?<br />
      <br />
      <br />
      <br />
    1. The Computer Audiophile's Avatar
      The Computer Audiophile -
      Correct. Unless you convert analog to digital before the Alpha DAC.
    1. shaq's Avatar
      shaq -
      Trying not to be a doofus here, but ...<br />
      <br />
      If I convert my phono to digital so that I can utilize the DAC and eliminate my preamp, I will be defeating the very analogue sound I enjoy, correct?<br />
      <br />
      Practically speaking, running the Berkeley straight into my amp eliminates my phono option. I have to stick with my preamp if I want to maintain my phono as best as possible. ???<br />
      <br />
      thank you<br />
    1. The Computer Audiophile's Avatar
      The Computer Audiophile -
      Exactly right. I just wanted to through the option out there for you to consider.
    1. jay's Avatar
      jay -
      Sorry for the dumb question, but wouldn't using the digital volume control on the Alpha essentially eliminate the "bit-perfect" signal going to the DAC inside? I understand that it would be bit-perfect when it hits the unit, but wouldn't the digital volume be applied before the DAC stage? Is there a type of digital volume control that hits the analog stage after the DAC got the bit-perfect signal?
    1. The Computer Audiophile's Avatar
      The Computer Audiophile -
      Hi Jay - Very good question and one that is best addressed by the people at Berkeley Audio Design. But, I will give you my opinion on this one for what it's worth. A digital volume control, as well as many other things, will most likely change the audio stream so it's not bit perfect. However, delivering a bit perfect stream to the unit itself is probably OK with the Alpha DAC. I'm guessing most other DACs change the audio stream sometime between when it hits the unit and when it's delivered to the actual DAC chip. Upsampling and downsampling are very popular whether a consumer is aware of it or not. For example some DACs allow you to enable upsampling while others upsample without you even knowing. I guess the signal is likely to be changed at some point before the actual DAC chip with most DACs. I think if implemented correctly a digital volume control can be great as it allows you to remove the filter of a preamp and additional cables. <br />
      <br />
      This is just my guess on the situation and it could be totally off base. Hopefully someone can jump in and lend a hand with the subject :=)<br />
      <br />
      <br />
      <br />