[AlanC]

Hi James,

Given the intention to bring the USB interface of the BDA-1 up to the same capability as the other interfaces (i.e. 24/192) and the developments in this area over the past few months, I wanted to give you an idea of at least my requirements, which hopefully others will contribute to, and get your view on potential product development.

There is significant interest in asynchronous USB across many of the forums and user groups as a solution to get audio data directly from a computer to a DAC without going via an interface such as SPDIF with an embedded clock in the data stream. The thought is that having the master clock as close to the DAC as possible with asynchronous delivery of data from the computer should give the lowest possible jitter and that this can significantly improve the sound beyond even the best jitter reduction techniques.

With Bryston's proven expertise in power supplies, clocks and analogue output stages etc that make up a great DAC design, adding this capability in my view would make the BDA-1 the DAC to own and reading this circle, there are a large number of BDA-1 admirers that may well agree?

As I see it, there are two particularly credible solutions that have come to market this year that if it was felt appropriate, Bryston could partner with, both of which have solutions for Windows and MAC that provide asynchronous USB at 24/192 - Gordon Rankin at Wavelength Audio (http://www.usbdacs.com/hs24192/hs24192.html) and Nadia Marino/ Marco Manunta at M2Tech (http://www.m2tech.biz/products.html). The M2Tech solution provides custom drivers for both Windows and MAC whereas Wavelength have had a USB Audio Class 2 driver written for Windows and is able to make use of the native USB Audio Class 2 driver in OSX 10.6.4 & above on the MAC.

Wavelength have licenced their technology to Ayre Acoustics who have produced this white paper which I think provides a good high-level overview for anybody interested this concept (incidentally, the whitepaper has not yet been updated to include the 24/192 ability that Wavelength and Ayre are both now releasing but the principle remains the same, with the exception of the aforementioned USB Audio Class 2 driver for Windows): http://www.ayre.com/pdf/Ayre_USB_DAC_White_Paper.pdf

BTW, it seems some people have managed to get a USB Audio Class 2 driver working in Linux with the Ayre/Wavelength solution that could be ideal as an alternative (superior?) interface option between the BDP-1 and the BDA-1:http://www.computeraudiophile.com/content/Ayre-QB-9-w-USB-Audio-v20-here-w-Linux-Update-It-WORKS. In addition, M2Tech say they are planning to release Linux drivers for their devices.

It would be really interesting if you were able to perform some listening tests - especially to compare to your existing computer set-ups with the Lynx AES and M-Audio SPDIF PCI cards - and connect up either the Wavelength Audio WaveLink HS 24/192 USB/SPDIF converter and/or the M2Tech HiFace Evo 24/192 USB/SPDIF/I2S converter to decent power supplies and wire directly into the I2S interface within the BDA-1 i.e. as you do with the existing USB implementation.

List of my requirements, in addition to existing BDA-1 functionality (all - please add anything I may have missed):

True asynchronous galvanically-isolated USB interface directly into I2S interface within BDA-1
Support for 16bit 44.1/48KHz and 24bit 44.1/48/88.2/96/176.4/192 audio
O/S Support for Windows XP, Vista, Windows7 and MAC OSX
Support for Kernel Streaming, ASIO, WASAPI, Direct Sound (Windows)
Ability for playback application (e.g. Foobar, WinAmp, J River, Amarra) to auto-change sampling rate based on audio file being played

James, I can feel my credit card trembling at the the thought of you building this functionality into the BDA-1 - it would become the ultimate DAC in my book.



Alan

[James Tanner]

Thanks for the input Alan - much appreciated.  I will certainly run it by the engineering guys.


james

[K Shep]

There is significant interest in asynchronous USB across many of the forums and user groups as a solution to get audio data directly from a computer to a DAC without going via an interface such as SPDIF with an embedded clock in the data stream.

With Bryston's proven expertise in power supplies, clocks and analogue output stages etc that make up a great DAC design, adding this capability in my view would make the BDA-1 the DAC to own and reading this circle, there are a large number of BDA-1 admirers that may well agree?

I purchased an Ayre USB DAC one year ago after listening to the unit at a local audio shop, feel in love with the "analog" sound that the unit produced.  The simplicity of USB out from my Mac Mini into the DAC was a huge selling point too.  I read about the asynch technology and was happy with my DAC.

I recently had the opportunity to demo a BDA-1 in my room next to my Ayre utilizing the USB input of the Bryston.  What does jitter sound like?  Believe me, I listened to it and listen more, and switch between the two...today I am listening to the BDA-1 with my Transparent USB cable and love the result.

Please don't believe everything you read in publications about which feature and benefit best suits an application until trying it for yourself.  Take it from a guy who was very happy to own Stereophiles Product of the Year 2009.  What I found is that in my room, with my ear, I prefer a different DAC (Bryston BDA-1) using its USB input which one publication describes as "dull and resolution-limited". 

Don't knock it til you try it.

[Napalm]

Dunno, I personally wouldn't buy anything from someone with such attitude:

""Specs? I don't know what the hell they are...let me look in the owner's manual. Oh! I can tell you what its dimension are, so you can figure out whether or not it will fit on your shelf. We don't do much with specs, because specs have very little to do with how the thing sounds."

http://www.stereophile.com/hirezplayers/705ayre/

Nap. 

[werd]

Hi Alanc

You would be amazed at how well hirez 2496 sounds over regular redbook into the usb of the BDA. I was looking at one of those April music usb converters. They look like they are competing against Bel canto for price and size. Anyways i am not sure i even need one. The hirez straight into the usb has far more body and with a  wider and higher soundstage than when i run a 1648 wav. file. 

granted i would still like to see at least an up to date usb on the bda.

[Mag]

Recently I made a back up copy of a cd using jitter correction on the software. Playing this back through the BCD-1 which already has pretty low jitter. I perceived a marginal difference. The bass a little more articulate and the volume a few decibels louder.

This leads me to believe jitter, which I understand is timing alignment of the wave. Is critical in achieving optimal sound from a recording.

[Napalm]

Recently I made a back up copy of a cd using jitter correction on the software. Playing this back through the BCD-1 which already has pretty low jitter. I perceived a marginal difference. The bass a little more articulate and the volume a few decibels louder.

This leads me to believe jitter, which I understand is timing alignment of the wave. Is critical in achieving optimal sound from a recording.

Mag, the "CD jitter correction" thing in rippers is referring to a completely different issue. On audio CDs (due to how information is stored) some computer CD units are unable to properly access the exact beginning of sectors when reading them as data  - they "slip" back and forth, producing very small gaps or repeats audible as "clicks".

It is highly recommended that you use it. However this "jitter" is not the same thing as the clock inconsistencies when playing the data (which, to confuse things, was named "jitter" too).

Nap,

[Mag]

Mag, the "CD jitter correction" thing in rippers is referring to a completely different issue. On audio CDs (due to how information is stored) some computer CD units are unable to properly access the exact beginning of sectors when reading them as data  - they "slip" back and forth, producing very small gaps or repeats audible as "clicks".

It is highly recommended that you use it. However this "jitter" is not the same thing as the clock inconsistencies when playing the data (which, to confuse things, was named "jitter" too).

Nap,

Oh, well it seems to make a difference. Perhaps the cd-rom drive is more advanced than my standalone burner. The sound of the track is comparable to what I heard at Werd's place. The music has what I call presence to it, now.

[Marius]

Hello All, james,

Probably because I don't yet fully understand the techniques of digital music, but still: why is this necessary: "Knowing that the BDA-1’s USB 1.1 input is limited to sample rates of 48kHz or lower, I used a Bel Canto USB Link 24/96 adapter (see John Atkinson’s review in the May 2009 Stereophile, Vol.32 No.5) to connect my Lenovo X61 laptop’s USB feed to one of the Bryston’s S/PDIF inputs with audio data up to 96kHz sample rates." (see http://www.bryston.com/pdfs/09/sp_bda_0110.pdf) and doesn't the BDA1 support this? Seems odd to have the best DAC around without native support for HiREZ audiofiles, apparently the audio-industry's future?
Will there be an update to make it support Hirez USB?

Thanx,
Marius

[AlanC]

Hi James,

Did you have a conversation with engineering regarding updating the BDA-1 with asynch 24/192 USB input as per my post back in the summer?

I notice on another link that you are updating the buttons on the BDA-1 early next year and hoped that this heralded a BDA-1 MKII re-engineering exercise? 

I also see that some of your BDP-1 customers would be interested in connecting to the BDA-1 via asynch hi-rez USB - in my mind that would be an awesome combination with the clock generation being performed right close the DAC chipset:

http://www.audiocircle.com/index.php?topic=82098.480


James,

Any reason why the BDP-1 could not be set up to output 24/192 USB for those with hi-hiz USB DAC's in addition to AES or S/PDIF?  Linux already supports USB to 24/192 in Voyage MPD 0.16+ so it should be a configuration change only.

I'm using an Alix/Voyage MPD motherboard 16/44khz right now into my Bryston BDA-1 USB input, just learning about MPD and various MPD clients, and it seems to work just fine.

Tom

Lots of interest on other hi-re computer sites too for this functionality, especially has more external DACs have come to market with this feature over the past view weeks:
http://www.computeraudiophile.com/content/Any-async-surprises-coming-CES

Here's hoping that you can reveal some good news, once you have it. 

Many thanks.



Alan

[James Tanner]

Hi Alan

Sorry sir bad news. I did speak to engineering and it would mean a redesign of the BDA. With the introduction of the BDP-1 digital player to mate with the BDA we feel that is the better approach for playing back digital files at thIs point.

James