[ian.ameline]

Interesting review of the BDA-1 here;

http://www.audiocircle.com/index.php?topic=64204.0

-- Ian.

[vegasdave]

Not bad.

[werd]

Jim,

Have not looked at all into anything using USB as it does not support high resolution, what is one of my objectives.
There is a solution from Empirical Audio that supports 24/96, but it requires too much customization to achieve optimal performance.

I was wandering if anyone has tried partnering Empirical audio's Turbo 2 Offramp into the BDA-1? Giving that the offramp passes 24/96 resolution, it might be a nice combo.

[werd]

Hi james,

why is the USB input limited to 48/16 ? is it due to UBS 1.0 , could be be better with USB 2.0 ?  i tried a 96Khz / 24 bits linn file but unfortunately i noticed that the input led was set to 48K. 
I got a BDA-1 for testing during the christmas hollidays: I use an Audionet Art V2 integrated CD player (+BP26 + 4BSST). I noticed a wider soundtstage but the BDA is also also a little bit dryer compared to the audionet (may be due to different cables for XLR and RCA connection). The upsampling facility is for me clearly audible and contribute to the wider soundstage.
A many others I would like to use BDA-1 as a maily a way to play files with resolution higher than a CD : regarding the input connectors what are the different possible sources. 

Phurbag

Hi Phurbag,

Correct the USB is version 1 (48/16) and will be updated to version 2 once the new chips are available.
44.1K/16bit is CD quality so that is still the case with the USB input.

All the other inputs are 192/24 capable and most quality sound cards have COAX or AES/EBU outputs which will give you native 192/24.

The thing to remember here though is not to get too caught up in resolution bits -- as with our CD Player  -- the main advantage and the reason we are getting such kick-ass reviews on the CD Player and the DAC is because the digital stage is state of the art but so to is the Class A analog stages and power supply technology around the DAC's.

james

I am really impressed with ability to  toggle between 16 and 24 bit resolution. I've always been under the impression that the higher sample rates have been better. But after listening to what u guys have done around native 48/16 bit sample rate its shaken my preconceptions. Its really a statement on what James said in the quote above regarding the power supply and analogue circuits employed. As much as I like the upsampled rate i find the bypassed rate to be very enjoyable. To me the leading edges and transients are more analogue sounding compared to the higher sampled rate. Its like "IN YO FACE Wadia, Meridian.... listen to what we can do with just 16 bits"...lol

Gratz

[predrag]

My BDA1 has arrived today (Serial No.105).
I am no expert in digital gadgets but first impression is OH LA LA...
My digital chain looks like this: iPod 160Gb - Wadia transport 170i - BDA1
This was my first contact with iPod and Co. and I was stunned.
Three of my friends have been listening to this and (blind test) guessing what was playing, BCD 1 or above mentioned components.
The difference was so little that success rate at guessing was below 70%.
Tomorrow I will try laptops (Mac and PC).
My tonight` s conclusion was that mainly DAC determines the final sound quality.
And what a DAC this BDA 1 is!
Bryston guys Bravo for you once again!

[James Tanner]

Hi All,

Another FIVE STAR review on the Bryston External DAC.

http://whathifi.com/Review/Bryston-BDA-1/

james

[James Tanner]

Bryston BDA-1 External DAC got the front cover of HI-FI Choice - not to mention a great review.

http://bryston.com/pdfs/09/hfc0902-bda1.pdf


james

PS - it's a BIG file - 7M

[budt]

   What is the canadian MSRP?

[James Tanner]

   What is the canadian MSRP?

\

Currently $1995 but soon to change do to currency fluctuations.

james

[drubin]

I was wandering if anyone has tried partnering Empirical audio's Turbo 2 Offramp into the BDA-1? Giving that the offramp passes 24/96 resolution, it might be a nice combo.

I am doing just that (I have the new Turbo3).  I have not yet done a direct comparison with the BDA-1's USB input, but the sound I'm getting now via the Offramp is wonderful.  The BDA-1 is a remarkable DAC.  I'm surprised the buzz about is not louder.

[James Tanner]

I was wandering if anyone has tried partnering Empirical audio's Turbo 2 Offramp into the BDA-1? Giving that the offramp passes 24/96 resolution, it might be a nice combo.

I am doing just that (I have the new Turbo3).  I have not yet done a direct comparison with the BDA-1's USB input, but the sound I'm getting now via the Offramp is wonderful.  The BDA-1 is a remarkable DAC.  I'm surprised the buzz about is not louder.

Hi drubin,

I would really be interested in your feedback regarding the Turbo vs the sraight in USB on the BDA-1.  We do not convert to SPDIF on our USB input but leave it as native I2S and then upsample the signal from there. 

If I understand the Turbo 3 it takes the 44/16 and upsamples it to 96/24 then outputs it to SPDIF?

james

[bob stern]

Empirical Audio licenses the firmware for the TAS1020 USB receiver from Centrance.  Centrance uses the "adaptive" mode in which the PLL in the USB receiver adapts to the clock rate from the computer's USB output.
http://centrance.com/licensing/clients.shtml

Wavelength Audio (Gordon Rankin) wrote firmware for the TAS1020 that instead uses the "asynchronous" mode in the TAS1020 USB receiver in which the USB receiver is clocked by the fixed frequency, low jitter clock from the DAC chip.  It uses the input data buffer of the USB receiver to hold bursts of data from the computer's USB output, and it commands the computer to send data to keep the buffer full.

Ayre licensed Gordon Rankin's firmware for their upcoming USB DAC.  In Ayre's white paper, the section "A Step Forward" describes the clocking method previously used by Rankin and still used by Empirical Audio and Centrance.  The section "A New Era" on the last page describes the new async method.
http://www.ayre.com/PDF/Ayre_USB_DAC_White_Paper.pdf

I hope that Bryston discusses a possible license with Gordon Rankin before deciding on its next upgrade to the USB receiver.

[James Tanner]

Empirical Audio licenses the firmware for the TAS1020 USB receiver from Centrance.  Centrance uses the "adaptive" mode in which the PLL in the USB receiver adapts to the clock rate from the computer's USB output.
http://centrance.com/licensing/clients.shtml

Wavelength Audio (Gordon Rankin) wrote firmware for the TAS1020 that instead uses the "asynchronous" mode in the TAS1020 USB receiver in which the USB receiver is clocked by the fixed frequency, low jitter clock from the DAC chip.  It uses the input data buffer of the USB receiver to hold bursts of data from the computer's USB output, and it commands the computer to send data to keep the buffer full.

Ayre licensed Gordon Rankin's firmware for their upcoming USB DAC.  In Ayre's white paper, the section "A Step Forward" describes the clocking method previously used by Rankin and still used by Empirical Audio and Centrance.  The section "A New Era" on the last page describes the new async method.
http://www.ayre.com/PDF/Ayre_USB_DAC_White_Paper.pdf

I hope that Bryston discusses a possible license with Gordon Rankin before deciding on its next upgrade to the USB receiver.

Hi Bob,

Thanks, that was informative.  Does it look like USB will eventually be capable of 192/24 at some point?

james

[drubin]

If I understand the Turbo 3 it takes the 44/16 and upsamples it to 96/24 then outputs it to SPDIF?

I don't think it upsamples, though I am not sure.  However, it will pass 24/94 from your computer, which the BDA-1 will not via USB.  It outputs to your choice of SPDIF, AES/EBU or I2S.  I'm using SPDIF out to the BDA-1.

In answer to your other question, James, Steve Nugent of Empirical Audio says that 24/192 is indeed possible via USB and he hope to have something implemented this year.

I agree with Bob Stern in recommending that you look at Gordon Rankin's technology.  As well as Steve Nugent's.

Dan

[bob stern]

According to Gordon Rankin, 192 KHz requires USB 2 plus a further enhancement called "USB Audio Device Class 2".  The streaming audio controller chips from TI are only USB 1.1.  Furthermore, Gordon says that only Mac OS X supports USB Audio Device Class 2; Windows and Linux do not.

http://db.audioasylum.com/cgi/m.mpl?forum=pcaudio&n=45489

http://db.audioasylum.com/cgi/m.mpl?forum=pcaudio&n=43493

http://db.audioasylum.com/cgi/m.mpl?forum=pcaudio&n=45421

http://db.audioasylum.com/cgi/m.mpl?forum=pcaudio&n=44280

[James Tanner]

Well it certainly is going to be interesting as we move forward.

I was speaking with a well respected digital engineer the other day and his opinion was that Ethernet was the way forward for transferring hi-res digital files and (this blew me away) the software controlling the interfaces are far more important for quality that the hardware.

The pro market which has been developing and working with computer audio for many years and according to him are way ahead of the so called 'prosumer' (his words) products currently on the market.

Interesting times indeed.

james

[bob stern]

I was speaking with a well respected digital engineer the other day and his opinion was that Ethernet was the way forward for transferring hi-res digital files and (this blew me away) the software controlling the interfaces are far more important for quality that the hardware.

This relates to your previous posts on the subject of whether Bryston should develop a music server product.  The problem with Ethernet is that, unlike USB, no computer has built-in capability of streaming music via Ethernet without installing server software, such as the Logitech Slim Server, on the computer.  (The "Music Vault" music server that was popular at CES is merely a Windows computer with a copy of Slim Server installed.) 

The disadvantage of server software is that the user is limited to the music library interface built into the client software available for that specific server software, whereas with USB the user can select any music player software he wants.  In particular, most users seem to prefer the interface of the iTunes music player over the Logitech server/client. 

A few companies such as Olive, Sooloos and Sonic Studio (Amarra) have made a huge investment in developing their own server/client software with an improved user interface.  Alternatively, someone could offer an improved user interface by developing an improved client for the public domain Slim Server.   However, such software development would seem risky for Bryston in view of the rapidly changing environment.

[Sasha]

Well it certainly is going to be interesting as we move forward.

I was speaking with a well respected digital engineer the other day and his opinion was that Ethernet was the way forward for transferring hi-res digital files and (this blew me away) the software controlling the interfaces are far more important for quality that the hardware.

The pro market which has been developing and working with computer audio for many years and according to him are way ahead of the so called 'prosumer' (his words) products currently on the market.

Interesting times indeed.

james

James,

Were there any specific pro market products (being ahead of prosumer products) mentioned in your conversation?

[James Tanner]

Well it certainly is going to be interesting as we move forward.

I was speaking with a well respected digital engineer the other day and his opinion was that Ethernet was the way forward for transferring hi-res digital files and (this blew me away) the software controlling the interfaces are far more important for quality that the hardware.

The pro market which has been developing and working with computer audio for many years and according to him are way ahead of the so called 'prosumer' (his words) products currently on the market.

Interesting times indeed.

james

James,

Were there any specific pro market products (being ahead of prosumer products) mentioned in your conversation?

Hi Sasha,

No specfic products mentioned just the fact that custom software was required to take hi-res audio playback to the next level.  What is out there is not considered hi-end according to my conversations. 

james

[wavelength]

James and the rest of the gang,

Bob emailed me yesterday so I figure I would clear up a few things about USB.

First if your willing to write drivers for all os's then USB is wide open. I did this for years and would rather not do it again. Therefore I like to use what is called the Native drivers.

Now there is USB 1.1 and USB 2.0 but really when we talk audio it is Class 1 or Class 2 that really makes a difference. Class 1 was the basic audio specification which includes all rates up to 102,3K sampling rate. Why? Because the Class 1 spec says that an audio frame will happen ounce ever 1ms or greater. The specification says only 1023 bytes per frame is allowed thereby setting the max rate to 102,3K.

First the Class 2 Audio spec is only supported under MAC OSX 10.5.x and greater. There is no present plans to do Class 2 on Windows or Linux, though I am betting within a year from now that this will happen.

The big problem is that to get to xx/192 (I say xx as I am working on the ESS part and have 32/96 working and should have 32/192 soon) you need both High Speed USB 2.0 and Class 2. In the Class 2 audio spec you can now use what are called sub frames. This allows you to basically send a sub frame every 146uS which means you can pass some serious data.

The big difference and something that I have been working on for like the last 5 years is the jitter is not really understood that much. I have been saying the following and testing seems to back it up that the use of upsamplers or FIFO reclocking devices only act as like a low pass filter to jitter. You can pour though JA's testing and see that this is the case in many of the USB input tests the jitter is significantly higher than the SPDIF inputs on the same dac. I believe that the damage is done before the upsamplers and FIFO reclocking systems and that not all of this is removed or can be removed.

So we basically have two types of USB Interface for audio ASYNC and Adaptive. With Async you also have PLL generated clocks (not good) or low jitter clocks that are connected at the dac and feed back to the USB controller (TAS1020 or others) and that clock is used to generate the Bit Clock and the Word Clock as well as clock out the data.

As an example here is some jitter numbers I did using the Wavecrest jitter measurement system on Word Clock. I used the Faber Acoustics Oscillator (Fs=44.1K) as the basis for the stream sending a 1KHz Sine wave to the unit under test. FYI Word Clock is always used for jitter measurements as it will always be the worst case and this does not reflect the overall jitter of the system as most current chips do have a fair amount of jitter rejection. But this is measured at the output of the Word Clock for the following chips and or software:

TAS1020 standard Adaptive Word Clock Jitter 2838ps
TAS1020 using my slow Adaptive code 1131ps
TI/BB PCM2706/07 I2S output Word Clock 3743ps
TAS1020 using PLL derived asynchronous output I2S 433ps
TAS1020 using low jitter MCLK input at 11.2896MHz 73.2ps

The main problem with Adaptive is that in a sense you are changing the clock in the USB controller every 1ms. In the TI reference code for the TAS1020 this is set to 4ms which makes it better and why you see and improvement from 3743ps to 2838ps but if the Soft PLL is made to work a little smarter you can see it can be improved even more to 1131ps. But you can really see that removing the 1ms change required to meet the Adaptive USB and going to Asynchronous USB that you really start to get into acceptable territory.

I am not really a fan of upsampler chips because the math units in these are always compromised. The good thing is that the computer upsamplers use floating point and have a ton more processing power and to me always sound better. But as you can see from above, reduction of the jitter going to the dac chip would be a requirement for any of the adaptive USB setups to meet High End standards.

James if you have any questions on USB don't hesitate to ask. I have been pretty open with my information. I think USB is really the only interface capable of High End Audio. Sure Ethernet or any connection will work but then you have to write drivers. Firewire really could have been it but they sat on their laurels for years and now even Apple is taking it off their product line.

Well back to work, thanks
Gordon
Wavelength Audio