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Implications of Esoteric G-0Rb atomic clock

The latest TAS (March 2008) has an excellent piece by Robert Harley: a review of the Esoteric G-0Rb Master Clock Generator, with sidebars on the history and significance of jitter. This Esoteric unit employs an atomic clock (using rubidium) to take timing precision to a new level, at least for consumer gear. It's a good read, I recommend it.

If I am reading all of this correctly, I reach the following conclusions:

(1) Jitter is more important sonically than we might have thought

(2) Better jitter reduction at the A-D side of things will yield significant benefits, which means we can look forward to another of round remasters (of analog tapes) once atomic clock solutions make it into mastering labs

(3) All of the Superclocks, claims of vanishingly low jitter, reclocking DACs -- all of this stuff that's out there now, while probably heading in the right direction, still falls fall short of what's possible and needed if we are to get the best out of digital and fully realize its promise.

(4) We can expect to see atomic clocks in our future DACs and CDPs. Really?

Am I drawing the right conclusions?
drubin

Showing 3 responses by agear

agear
1,362 posts
 
There is some confusion in the above thread about USB (at least as we know it....) Here is what Steve Nugent has to say about this subject:

USB indeed does transfer a clock, similar to the way that S/PDIF has an embedded clock. The primary difference between the two is that the chips available for clock recovery for USB are actually better at jitter rejection than the receiver chips for S/PDIF clock recovery. That is the primary advantage of USB, as well as an apparent lower sensitivity over long USB cables compared to long S/PDIF cables.

And the Synchronization comment is false. These interfaces all use forms of Phase-locked-loops or delay-locked-loops. The rubidium clock or a Superclock are just providing a low-jitter clock for the PLL. Nothing to do with "synchronization". Both USB and S/PDIF have embedded clocks.

An I2S interface actually has separated clocks, so this is a big advantage and results in even lower jitter than USB or S/PDIF.

Steve N.
agear
1,362 posts
 
Eric, I agree in essence with what you are saying. S/PDIF is inherently flawed. USB has advantages in terms of the ease of reclocking, etc. However, not all USB interfaces are created equal. Steven Nugent himself told me that there is a fair amount of variability in the quality of USB reclocking chips, which is where the $ is. That being said, I wonder if the sonic attributes of this WDP (nice Dgarretson....) are simply a byproduct of the USB interface or is it something more? I think you are operating under certain assumptions about the purported sonic attributes of USB data architecture. There are USB products out there which, while very good, are not a quantum leap beyond current offerings.

I will leave you with a quote from the Benchmark gang taken from a Stereophile thread:

We did measure the audio performance (Freq response, THD, IMD, etc) of the USB input, and it was completely similar to the all other digital inputs of the DAC1 up to 96/24. We also did listening tests. I am continuously conducting this test (as we speak ), as are several others here at Benchmark. Testing with a CD transport feeding the Coax input, and the computer feeding the USB with the same music, no one has been able to differentiate the two inputs.

--------------------
Elias Gwinn
Engineer
Benchmark Media Systems, Inc
www.BenchmarkMedia.com
agear
1,362 posts
 
Eric, you soooo right. We are all sick of this crap. I have been researching and researching and waiting for "that" product to appear but to no avail. One of the sonic themes that comes out in reading reviews pretaining to digital audio is a certain thinness of sound...ultra detailed yes, but lacking warmth, bloom, bass weight, etc. That is what I crave. You mentioned the Memory Player, and while it sounds promising, who is 10K+ lying around? Anyway, I am planning to a little blinded, A+B testing of digital front ends in the not too near future, and I would like to involve non-audiophiles with good ears and music backgrounds (my wife for example) to keep things real. The potential contenders at this point are:

1. Granite Audio 657 (my CDP)
2. Bolder modded SB3 (Ultimate mod)
3. Modded Sonos + Pacecar + DAC (Empirical Audio)
4. Sonos (w/ ? USB mod or converter) + Exemplar USB DAC

Should be interesting.....
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