New Berkeley DAC? This article implies as much but ... ?

[Elberoth]

No word clock input.

 

I wish more DACs supported word clock input. The number of devices that work with external word clocks (servers and DACs) is extremely low.

 

I belive you meant output ? WClk input on a DAC doesn't make much sense. It is best to put a free running (no PLL), high quality clock inside the DAC and send the clock signal back to the transport, not other way round.

[Elberoth]

If it adds jitter why is it so common in the studio environment?

For home audio, you are only using it to reference one signal.

 

Because you have to sync multiple boxes - many, many more than in a home audio. Lower jitter is only secondary consideration.

[Elberoth]

Additional cabling aside (good point Barrows) a word clock input is nice when you already own a clock like an Antelope Atomic, etc...

 

Atomic clocks are pure marketing. They do have great accuracy, but accuracy is ... not really very important for audio replay. What you are looking for is short term stability, which has a direct effect on jitter. In that regard, $30 Crystek XO (as used in Berkeley stuff, among others) will easily beat the Rubidium Oscilator, like the cheap Spectra Time module used in the Antelope 10M.

 

Plus, you will never be able to even get the phase noise figures the manufacturer of the rubidium clock is quoting, since you need a PLL to convert 10MHz signal (this is standard for all rubidium clocks) for something usable for audio replay (read: 44.1kHz or 48kHz family).

 

XOs on another hand, have much lower phase noise figures, and can be ordered in the desired audio freq (no PLL necessary).

 

I recommend to everyone an excellent Grimm Audio White Paper on clocks - it is excellent read !

 

http://www.grimmaudio.com/site/assets/files/1088/picoseconds_or_ppm.pdf

 

Mytek, Antelope and others have had word clock inputs for quite some time.

 

That is because they are primarily targeted at the pro market.

[Elberoth]

Thanks for posting the Grimm pdf Adam. I hope your post puts to rest all the nonsense regarding atomic clocks and audio. Long term accuracy has nothing to do with audio performance.

 

Just to clarify: Rubidum clocks do sound good. Afterall - they do have good phase noise figures. But why bother spending $800 on a Spectratime LCR-900 module (as used in the Antelope 10M) or $1400 on PRS-10 (as used by Esoteric), when a $30 Crystek part can offer a better performance ?

[Elberoth]

The fact that Antelope sells any of their more expensive ones to the pro market is indeed a wonder of the world, then. ?

 

It is a good clock. And the magic word 'Atomic' does wonders in terms of marketing and sales

[Elberoth]

It is much better to send the clock signal over a few mm of well engineered, impedance controlled PCB trace, than it is to send it over a cable, through multiple jacks and plugs, none of which can be "perfect" from an impedance standpoint.

 

Don't forget about the PLL, that still has to be present on any DAC with WClk input. It also adds considerable amount of jitter.

[Elberoth]

A lot of people agree on this, but dCS obviously did not get the memo.

 

dCS started using external clocks on their pro-audio oriented gear, and then added this option to their audiophile range.

 

I was puzzled to see the external clock option on the Vivaldi line. But then again - maybe they thought that the compatibility with other models was more important. Afterall - not all Vivaldi buyers get the whole stack all at once. Many upgrade component by component.

[Elberoth]

Interesting indeed.