X32 Clock Sync Failure. Videos Attached

Re: X32 Clock Sync Failure. Videos Attached

OK folks I did the test that Christian did and got the same result's he did.

No need for a video

SHIELDED CAT5E WITH ETHERCON CONNECTORS ON EACH END. Shocked for more than 20 minutes straight without a drop out. Pulled the ethercon ends off and the problem presented itself once again.

So it looks like we have a solution to the problem. Always use SHIELDED ETHERCON CABLES

I checked continuity on the rj45 aes50 connectors and the left shield tab in grounded to the chassis of the desk but the right is not. Same goes for the S16. Once the ethercon connector is used the entire connector becomes grounded. I would guess that this solves the problem because of ground potential??
 
Re: X32 Clock Sync Failure. Videos Attached

Brian Wynn said:
I would guess that this solves the problem because of ground potential??
Click to expand...

I don't think that's why. It prevents any direct path of entry for high voltage static discharge directly into the audio circuity by having the shield cover 100% from end to end.
 
Re: X32 Clock Sync Failure. Videos Attached

I can speculate with the best, but i need to preface that I don't know for a fact.

My suspicion is that ground is not the same low impedance at HF as it is at LF, so a sudden fast rise time current transient, like from a static spark can cause a brief shift in the local ground due to inductance in the entire ground path all the way back to earth ground. So even with two chassis, plugged into the same outlet, the inductance in the line cord and wiring getting to the digital interface local ground could express as a voltage difference between grounds during such transients. Using a cable grounded to chassis at both ends will bond these two grounds to each other especially near to the digital interfaces. Without this additional ground bonding a static hit could cause enough of a logic threshold shift between the send and receive unit to lose sync momentarily. This sync recovers after this momentary voltage jump has passed.

So no I do not think that it is the shield as much as the extra ground bonding. Caveat lector, I am pretty much guessing about this.

JR

PS: And yes this creates a ground loop but so what? As long as the audio is treated differentially a ground loop does not matter. I guess hypothetically a huge magnetic field could impose and ac voltage across this loop that could also affect logic thresholds, but I wouldn't lose any sleep over this.
 
Re: X32 Clock Sync Failure. Videos Attached

John Roberts said:
PS: And yes this creates a ground loop but so what? As long as the audio is treated differentially a ground loop does not matter. I guess hypothetically a huge magnetic field could impose and ac voltage across this loop that could also affect logic thresholds, but I wouldn't lose any sleep over this.
Click to expand...

Back in my video days, the ground loops between interconnected gear in various rooms could cause some problems. Not all video switchers had isolation on their inputs and outputs. And since all video in those days and most presently use coax to move signals through facilities, fixes were difficult and expensive You can't use transformers as a fix with SDI signals. There one off the shelf solution for composite analog video, but the transformers were huge and expensive. At my day job now, we make SDI/HD-SDI BNC to fibre adapters that are hot sellers for this reason. It would be nice if these stage boxes and board had the option to use fibre optic cables instead of the twisted pair so you could mitigate both the static and loops issues. Yes, fibre in general isn't as robust as copper, but the snake grade stuff is pretty sturdy.
 
Re: X32 Clock Sync Failure. Videos Attached

There is still a lot of confusion between actual ground loops (a loop forming a one turn winding intersecting a magnetic field) and the more common ground potential differences from simple different ground currents flowing into different ground resistances. To the end user this distinction does not much matter, and good practices, treating important signals differentially and separate from grounds, can often ignore such differences.

While I haven't had much experience with video signals most I've seen were single ended so I can imagine that clean signal low grounds between chassis matter. I must admit that most of my exposure has been to consumer video not pro gear.

JR
 
Re: X32 Clock Sync Failure. Videos Attached

Brian Wynn said:
OK folks I did the test that Christian did and got the same result's he did.

No need for a video

SHIELDED CAT5E WITH ETHERCON CONNECTORS ON EACH END. Shocked for more than 20 minutes straight without a drop out. Pulled the ethercon ends off and the problem presented itself once again.

So it looks like we have a solution to the problem. Always use SHIELDED ETHERCON CABLES

I checked continuity on the rj45 aes50 connectors and the left shield tab in grounded to the chassis of the desk but the right is not. Same goes for the S16. Once the ethercon connector is used the entire connector becomes grounded. I would guess that this solves the problem because of ground potential??
Click to expand...

Dear Guys,

We recommend the following for all AES50 connections, (X32 to X32, X32 to S16 and between all S16 stageboxes).
1 - CAT-5e Shielded Cables ONLY
2 - Ethercon terminated cable ends
3 - Maximum AES50 cable length 100 meters (300')

I have used the Pro Co, (Pro Co 300' Shielded Cat 5e Ethercon Cable). It has a robust casing, Ethercon ends and is Shielded CAT-5e. In the US Sweetwater carries this cable in-stock, (Pro Co 200' Shielded Cat 5e Ethercon Cable | Sweetwater.com), you can select many different lengths up to 300'.
 
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