review 'db audio labs tranquility dac

I would have to agree with Trebejo.

Excellent question / observation regarding the dac's input choice.

db Audio Labs purposely chose not to include the interfaces suggested for very specific technical and MOST importantly, sonic reasons! Basically, for all the interfaces you suggest, some form of circuitry, albeit a chip or discrete componentry, must be included which connects to each of those interfaces and provides an I2S output signal which in turn provided to the dac chip.

So, in essence, each and every interface that you suggest (as well as the USB interface) must output an I2S signal to the dac. Typically, some sort of switching is used to select the respective I2S signal the interface desired. In order to optimize the I2S connectivity to the dac chip, the I2S data signal lines MUST be treated as RF transmission pathways and laid out accordingly. This is seldom if ever done in audiophile consumer products. But, we do it this way with the Tranquility design. In other words, audiophiles desiring numerous interface inputs as is what is typically seen from other dac products, more often than not, prevents optimal RF layout as the I2S signals must traverse the switching necessary thereby adversely affecting the overall sonic capability of those dacs period. So, less inputs makes RF layout manageable leading to better sound.

We also recognize a multiplexer could be used rather than switching. However, multiplexers are not without their own attended problems. As they too impede layout in their own right.

Another thing to consider when adding interfaces, since they are often in the form of some dedicated interface chip and are likely to require some clocking, i.e. an oscillator, for their operation. Those oscillators give rise to the potential of interfering and intermodulating with the oscillator that is in use for the interface selected. Obviously, this like switching, gives RISE to the potential for jitter and usually does, without exception!

dB Audio Labs selected to use USB because there is no correlation between the clock and the audio data. “Jitter”, as properly defined, requires that there is some sort of clock associated with the data. Absent that, there is NO jitter.

SPDIF includes data correlated with a clock thereby allowing for jitter to occur (not as good).

Firewire does not include data correlated with a clock and thereby does not give potential for the rise in jitter nor does USB (much better).

It should appreciated that both Firewire and USB have more than enough bandwidth necessary for the transfer of digital audio data.

However, there is one major distinction between Firewire and USB that is typically overlooked by audiophiles. That is to say, a dac manufacturer who decides to include a Firewire interface on their dac must provide, or be in the business of providing, developing and/or maintaining a Firewire device driver for EACH operating system, (Windows and MAC) for their digital product. And while some boutique manufacturers many be capable of doing such, there is obviously an intended cost to the consumer. Moreover, there exists the potential for a customer to have, for at least some brief period of time between operating system upgrades, for their dac to become inoperable as their current driver could be incompatible as a new version of their operating system is rolled out.

In contrast, USB dacs typically make use of those drivers found in both the Windows and Mac operating systems. USB specifications and standards require this! So, as long as the dac meets the “USB 1.1 / 2.0 standards”, you are golden. And yes, the Tranquility dac meets these standards!

So, rather than spending our time developing and maintaining Firewire drivers, we’ve selected USB connectivity for inclusion in the Tranquility design and put our efforts into developing the balance of necessary circuitry, e.g optimization of transmission paths, power supplies, dac optimizations, I/V stage, analog output stage, parts selection, etc..

We hope that you consider each and every one of these salient points we’ve outlined when selecting your own personal digital to analog converter. We obviously have, as from the foregoing explanations outlined above.

And that is why you only see a single solitary USB input on the Tranquility DAC ;-)

Yes, well, there are a gazillion music-computer tools that use firewire, and another gazillion that use usb.

The firewire kind is used by the pros.

The usb kind is used by the folks that shop at radio shack.

The reason, plain and simple, is that firewire piggybacks well while usb does it very poorly; firewire impacts the cpu far less than usb; usb can freeze your computer, firewire can basically never do that.

So why is usb more popular than firewire? Probably because one was promoted by Apple and the other by Microsoft.

I'm simply going to say that of all the serial interfaces, usb is among the most compromised and DEFINITELY not the one you want to use with an instrument that is simultaneously expensive, high-performance and meant to be long lasting.

I don't mean to rain on dbaudiolabs parade, but if there are people out there that are just getting started and wondering what is what, you can do well by simply avoiding usb for anything expensive, high-performance or long-lasting.

IF there was going to be a single input to your dac, it should be coaxial or optical. It should not be firewire for the reasons listed in the post above, although if it were, it might possibly be OK; it should not be usb, at the very least, for the reasons I have given here.

I am under the impression that there are audiophile reasons as well for not relying on usb, such as those in this article,

http://www.stereophile.com/digitalprocessors/cambridge_audio_azur_dacmagic_da_converter/index3.html

which basically states, among other things, that you have to think long and hard about how you are going to connect your computer to that USB cable.

A properly designed DAC (and you can certainly find them for hundreds of dollars less than the one being reviewed above) will not force you to do any such thinking about what your computer is doing on the other side of that optical/coax digital input cable; in fact, it might not even require you to turn on a computer at all. :)

A lot of competition for less money.♫

We understand why some posters could think USB connectivity may not be "audiophile approved". That's why we wrote the VERY thorough technical overview (posted earlier in this thread) for everyone to realize how USB connectivity could actually be a phenomenal sounding choice when it is designed and implemented correctly.

But, there are still some detractors that are skeptical, so here's some more food for thought to ponder and consider - It was recently announced "USB DAC Wins Stereophile's Overall Product of the Year!". Hmm, could Stereophile actually be on to something with their most recent assessments and accolades about USB connected DACs too?

And, from the outset, our inherent mission when we created the Tranquility design was - The true measure of any DAC design and its "inherent technology" comes down to HOW IT SOUNDS as compared the actual master tape!

It is our professional opinion that any given type of DAC solution that has the ability to give audiophiles better space rendition, portray the fragile high frequency harmonic overtones more accurately and subsequently sound more real, should "win the day" as the better DAC. This is how we would like to be "measured" by the audiophile community.