To be accurate
The use of atomic clock is highly controversial even among the sound engineers. Some say that as long as the DAC has a good clock, it doesn’t really matter as jitter is only a problem at D/A conversion.
Well, theory is theory, but when you have a chance to listern to a good master clock at work and pick 100% in a blinded A/B test, you will spend the money. For me, since I am running a few digital component at the same time, I have one more reason – to get synchronized.
Moving on to use AOIP, the clocking device will also have to be changed. instead of word clock, I moved to use PTPv2 network clock. There is one company that makes a clock for the Ravenna network. But I suspect any PTPv2 clock should work.
This Sonifex clock is connected to the switch and the clocking signal is distributed to the whole Ravenna network. So only one Cat 7 cable connection is enough. Gone with the days when I needs so many Coax cable and worried about signal reflections etc.
The above 3 screen is coming from the Advanced page user guide
Here is some more information
My current setup using Cisco switch has been having glitches every now and then. If I look at the clock jitter, it is pretty high considering that I am using a PTP clock already. After some research, it may be due to the fact that Cisco SG300/350 switch is not PTPV2 aware and I have to use E2E protocol to pass the time signal down. (E2E protocol can work with PTP unaware switch to a certain extent) I have a very elaborate system and that can cause some jitter. I am now planning to change the switch to a PTP aware switch and options are Netgear M4300 or Gigacore 20T. I have just placed an order for Gigacore 20T.
Here are some information from Luminex https://www.luminex.be/improve-your-timekeeping-with-ptpv2-2/
As you can see here is the clock that shows the jitter of my Mac Mini running BACCH. There is virtually no jitter. The Mac mini is connected to the Cisco Switch via Lan cable with RJ445 at both ends
Now here is the same clock at the Hapi terminal. You can see that there are a lot more jitter at this location. May be it is due to the way that it is connected. The signal from the Cisco switch is connected via the SPF+>optical cable and then the receiving end is a optical > RJ45 converter. I will try to see if using Lan cable can solve this problem. The other way to solve the problem is of course using a PTP aware switch
This is another view of the Hapi delta