Berkeley Audio Design Announces The Alpha USB Asynchronous Interface

Robert Harley -- Thu, 03/31/2011 - 20:45

I have the Berkeley Alpha USB up and running in my system right now, connected to an iMac. I'm comparing this configuration with my PC-based server fitted with a Lynx AES16 card, with both driving the Berkeley Alpha DAC. I'll have a full report in Issue 214.

Sam -- Thu, 03/31/2011 - 21:55

Robert, what USB cable are u using Between the Alpha USB and the computer? Also in ur review can u discuss the placement of alpha DAC, alpha USB, and the computer? Is that even relevant? looking forward to the review.

Nicholas.Bedworth -- Sat, 05/14/2011 - 11:27

On the really well-engineered devices, you can use a very long, el-cheapo USB cable, even with extenders, and get peak performance. These devices regenerate clocks internally, and don't seem to care about the USB cable. This in turns keeps the S/PDIF cable very short. With some products, you can plug the S/PDIF interface directly onto the DAC, eliminating the cost of the cable entirely, and assuring best performance.

Nicholas Bedworth  
DigitalDirect Media Services, LLC    Text/voice 1.808.372.2883 (GMT -10)   nicholas [dot] bedworth [at] digitaldirect [dot] com (nicholas.bedworth@digitaldi) -- Thu, 05/05/2011 - 21:01

Dear Robert,
I noticed that the Berkeley Alpha USB does not have a world clock input, which seems to me as a shortcoming.  
The Logitech Transporter (US$1300) has a world clock input.  Using a DAC that can provide an external world clock such as DACs from EMM Labs and DCS, would it be better to go with the Transporter, because using the world clock input (of course, I would not be using the DAC portion of the Transporter) would minimize jitter, or the Berkeley Alpha USB would be a superior digital transport connected to an EMM Labs (which I own) or DCS even though it does not have a clock input? 
Another option that I am looking into is the RME Fireface UC 36 (US$1,299) which also has a world clock input.

Nicholas.Bedworth -- Thu, 05/05/2011 - 21:08

Perhaps you mean "word" clock? Using which, of course, could make a "world" of difference. Using the Grimm CC-1 "house clock" (, only $495) adds all kinds of dimensionlity and realism when driving the Weiss DAC 202, which is an excellent product to start with.

Basically an ultra-low-jitter clock, with very low phase noise below, say, 100 Hz, seems to contribute to presence, air and overall "you are there-ness". The "injection" of the word clock often goes through a PLL, and depending upon the internal design of the DAC, some will benefit more than others, but it's definitely worth a try. And note the relatively modest price of admission: It's not necessary to get an "atomic" clock, which may have very high accuracy, but less-than-stellar phase noise. Jitter and phase noise are quite different from clock accuracy.

Nicholas Bedworth  
DigitalDirect Media Services, LLC    Text/voice 1.808.372.2883 (GMT -10)   nicholas [dot] bedworth [at] digitaldirect [dot] com (nicholas.bedworth@digitaldi) -- Thu, 05/05/2011 - 21:17

Correct, word clock. I read in many places that using the word clock output of the EMM LABS DCC2 SE into a digital transport improves substantially the performance, by reducing jitter. So I wonder how does the Berkeley, which does not have a word clock input, compares to the RME and Transporter (both have word clock input) when used with a high end DAC that has word clock output.

Nicholas.Bedworth -- Fri, 05/06/2011 - 01:10

Also word clocks tend to be more prevalent on DACs with recording industry heritage and application, such as the Weiss. In the studio, you'll want to have a house clock slaving a variety of devices. Again, not all DACs will benefit from the word clock, but some will sound radically better, if you have high-end amps and speakers.

Nicholas Bedworth  
DigitalDirect Media Services, LLC    Text/voice 1.808.372.2883 (GMT -10)   nicholas [dot] bedworth [at] digitaldirect [dot] com (nicholas.bedworth@digitaldi)

Nicholas.Bedworth -- Fri, 05/06/2011 - 02:11

That's $2495. My apologies for the typo.

Nicholas Bedworth  
DigitalDirect Media Services, LLC    Text/voice 1.808.372.2883 (GMT -10)   nicholas [dot] bedworth [at] digitaldirect [dot] com (nicholas.bedworth@digitaldi)

wdw -- Thu, 05/05/2011 - 02:59

 Hello Robert,
We just recently took delivery of a new Berkeley Audio Alpha DAC and must say that we're delighted and, in truth, shocked at how good it is.  When will issue 214 be published?  Very curious to read your comments on the Alpha USB.

Nicholas.Bedworth -- Fri, 05/06/2011 - 01:19

And at a lower price point, there is the $495 Audiophilleo2 USB-S/PDIF converter, which has jitter down in the 2.5 ps RMS (10 Hz-100 kHz) range.

Nicholas Bedworth  
DigitalDirect Media Services, LLC    Text/voice 1.808.372.2883 (GMT -10)   nicholas [dot] bedworth [at] digitaldirect [dot] com (nicholas.bedworth@digitaldi) -- Sat, 05/07/2011 - 08:57

 Hello Nicholas,
Thank you for pointing me to other options. The low measured jitter of Audiophilleo2 and 1, seem very promising.  
Do you know any USB to S/PDIF converter that accepts word clock in, and has audiophile quality? 
From all that I read, my EMM Labs DAC does sound much better when using is word clock as master, and I do have great preamp, amp, speakers, etc. 
Vicente -- Sat, 05/14/2011 - 11:15

 Dear Robert Harley and Nicholas,
So far the USB -> SPDIF converters, with word clock input that I have found are: 
- RME Fireface UC 36 - US$1,300
- MOTU 828 mk 3 - US$749
- Phonic Firefly 808 - US$499
- M2tech Hiface EVO - US$499 (22.5792MHz or 24.576MHz word clock input, which is an issue)
and in different way (not USB) the logitech Transporter
I have not seen any comparison of their performance, especially using the word clock input.  
I also have no idea of how they compare, using a high end dac with word clock out, compared to converters that do not have word clock input, such as: 
- Berkeley Alpha USB (US$1600)

- Audiphileo 1 and 2 (US$495)
Musical Fidelity V-Link (US$169)
I wonder if anyone has done a comparison, and if not, which one is expected to be the best (using a high end DAC that has word clock out)? 

Nicholas.Bedworth -- Sat, 05/14/2011 - 11:30

@vicente Isn't the M2Tech Evo clock input really more of a bit clock? Check with Marco at M2Tech. He's very knwledgeable and will tell you what they have in mmind.

My experience so far is that almost is most of the USB-S/PDIF interfaces have poor jitter performance, regardless of the marketing hype. Sure, asychronous USB is an important first step, but then what? Look for devices that have fixed-frequency internal crystal oscillators, and don't use output transformers to drive the S/PDIF cable.

And pester the manufacturers for the following:

1. What is the phase noise of their clocks and how did they measure it?
2. Failing that, what are their jitter specs? What type of jitter is it, and what are the bandwidth paramaters?

The best use of a word clock such as the Grimm CC-1 is with the DAC, not the USB-S/PDIF interface or processor. The Grimm has very low phase noise in the critical 0.1-100 Hz range, which seems to contribute to realism, presence, air and image coherence. Black Lion Audio has an inexpensive word clock but we haven't tested it yet.

BTW did you find this comparison chart? It has some data on several models. and may be helpful.

Nicholas Bedworth  
DigitalDirect Media Services, LLC    Text/voice 1.808.372.2883 (GMT -10)   nicholas [dot] bedworth [at] digitaldirect [dot] com (nicholas.bedworth@digitaldi) -- Sat, 05/14/2011 - 12:42

 Hello Nicholas,
I had seen the table when you first mentioned, but since most products don't show their jitter data, it not very useful in this respect. This is why I was asking if anyone has really compared the peformance of the many USB -> SPDIF devices I listed, and theLogitech Transporter, against those that do not have a word clock input, when connected to a high end DAC such as EMM and DCS that have a word clock output. I have not seen such comparison anywhere. 
I used to live in New York, but in Brazil you can not test equipment in your house before puchansing. You have to buy the one you think is best based on reviews and then try it against your existing system, so I would like to know reviews or oppions about which option is best.  I am not prepared to buy a separate clock, I would like to use the word clock out ot the EMM or not use a word clock at all if the other options are better. 

Nicholas.Bedworth -- Sat, 05/14/2011 - 12:51

The potential benefits of any word clock, firstly, depend upon how good it is, and secondly, how much the architecture of a DAC can make use of it. Although a DAC may have a word clock input, even if you give it the most perfect possible clocking information, the benefits, if any, will depend on how the DAC processes that clock. Typically the Word Clock input is received by a PLL, and it seems like every designer implements the PLL differently. Some PLLs are created more equally than others. :)

In any event, my experience is that with the Weiss DAC 202, an excellent product, a very low phase noise clock did provide a substantial improvement, but you'll only hear it on very high performance gear.

If you don't want an external clock, then you're dependent upon the clock phase noise of the USB-S/PDIF interface. If the designer of the device has gone to the trouble to provide a clock output, they should know what the phase noise and jitter are. Don't be afraid to e-mail them and ask. Some designers will be very pleased to receive such questions, because it allows them to talk bout how they solved some interesting problems.

What's more important than a clock output? For some applications, it will be features. If you look at the Audiophilleo1 processor, which has very low phase noise, it has preamplifier functions such as attenuation, channel balance, polarity reversal, etc., and these, on a day-to-day basis, may be much more important.

The USB-S/PDIF devices with such functions may allow you to take out a preamplifier, and have the DAC drive your amps directly, which is what we have always done here.

Which EMM DAC are you using? They have several consumer and professional models. You can e-mail me privately and we can continue the discussion off-line.

Nicholas Bedworth  
DigitalDirect Media Services, LLC    Text/voice 1.808.372.2883 (GMT -10)   nicholas [dot] bedworth [at] digitaldirect [dot] com (nicholas.bedworth@digitaldi) -- Sat, 05/14/2011 - 12:54

 Robert Harley has reviewed the DCS Puccini U-clock (US$4999). That device would be a great addition to the comparison list since it also converts USB. 

Sam -- Sun, 05/29/2011 - 10:07

Robert, you didn't compare the alpha USB which is suppose to be state of the art to the sooloos which also appears to be state of the art. Why skip on that? Especially if u have all 3 to test. so the alpha USB is better than the old Goodwin PC solution, but between the two current best, sooloos vs iMac on an alpha setup what difference is there if any? -- Sat, 06/11/2011 - 15:19

 Dear Robert Harley,
I just read your review of the Berkeley Alpha USB in TAS.  I would like to know more about the clock it uses, is it oven-controlled (OCXO)?
 I read that most of the best clocks are OCXO,  such as the one used by DCS U-clock (which is also a USB converter, and possibly better than the Berkeley Alpha USB, but I haven't read any comparison...), also used in word clocks such as Antelope OCX, and Esoteric G03x. 

Syd -- Sat, 06/11/2011 - 23:24

Just read your review of the Berkeley Alpha USB and want to understand more about how you used your iMac as a source.
1. Did you plug an external hard drive (with your music) into the  iMac via USB and then USB out to the Alpha USB box, or did you transfer everything to the internal iMac hard drive?
2. What format was the music that  "you" provided ripped in? What format was the Berkeley preinstalled music on the iMac ripped in?
3. Did you use an iPad/iPhone as a remote for your iMac  (with the iMac sitting somewhere else, like on your equipment rack for instance) or did you keep the iMac close to the listening chair and control it with the standard  keyboard/mouse?
4. Do you see any disadvantages with using a different Mac (e.g., Mac Mini or MacBook) versus the iMac as a front end to the Alpha Box?
The ergonomics of how you used the iMac is of interest to me.
- Syd

Willster -- Fri, 06/24/2011 - 01:34

I read the Berkeley Alpha USB review.  I must admit that I'm a bit frustrated by all the interest in the USB to SPDIF interface product category.  When the product costs $99, as the cheapest ones do, I can see maybe buying one, assuming it improves the sound.  After all, the better alternatives would probably cost more.  But I cannot see why anyone would spend more on the interface ($1700) than the computer source.  If what you want is SPDIF, start with SPDIF.  That kind of money would buy a very nice sound card with an SPDIF output.  The combined cost of the Mac laptop in the review and the Berkeley interface was approximately $2900.  If you must use a laptop, surely there are some at $2900 or below that have SPDIF output.  Alternatively, if you must, for some strange reason, use the crappy USB output and you are going to run it to an external DAC anyway, that additional $1700 would help you buy a much better DAC with a robust enough USB input and that would save you buying extra cabling and software and eliminate the need for locating the interface and it's power supply and high end power cord and, at these price points, probably expensive isolation shelving and/or support products.  There'd be many fewer connections, a simpler signal path and a lot less to go wrong.  Unless a person is just a gadget geek and has to have one of everything, I can't make sense of it in a typical home sound system.  It's an interim product at best.  A year from now you'd be selling it for the inevitably better alternative that is bound to come along if one isn't already available.  Of course, I suppose if you have a "reference" system at the price point of the one Harley used in the review, $1700 is trivial to you.
I expressed much of this in an email to Robert Harley but did not receive a reply.  I suspect my frustration caused my message to be overly provacative and probably pissed him off. 

dbk1 -- Sat, 06/25/2011 - 16:18

I am using a MacBook Pro laptop with all of my music ripped from CDs to Apple Lossless format output to a DAC1 USB output to an Eddie Current Zana Deux tube amp using Grado GS-1000 Head Phones

I was wondering if the Berkeley Alpha USB to SPDIF would enhance the above combination of components to any real world degree?
I was looking for an upgrade path and thought this would make sense. Anyone have an opinion??

Thanks for the advice.


email: kuriloff [at] nyhni [dot] org

Syd -- Sat, 07/09/2011 - 22:53

 RH - You have beed noticeably silent.  I would love to hear your response to my 6/11/11 post.

ipadjongen -- Mon, 07/11/2011 - 11:54

@Willster: "C’est le ton qui fait la musique"  (It's not what you say but how you say it). I know mr Harley as a very kind man.
How difficult is it for you to show some respect.

If music be the food of love, play on,
Give me excess of it; that surfeiting,
The appetite may sicken, and so die.
Shakespeare, Twelfth Night Act 1, scene

Aryoh -- Wed, 08/10/2011 - 13:09

I realy dont know why people get frustrated about price of some hi fi gear, they could buy some cheap design that do the work. leave mr Harley at peace he is just another audiophile that love good components. So if you dont like Berkeley go and buy some cheaper design, if that satisfy you.
Sorry for my english

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