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Author Topic: AES50 dropout during subharmonics/anything under sustained 50hz  (Read 2655 times)

Scott Holtzman

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #40 on: May 21, 2018, 11:27:17 pm »

The problem is those expensive testers are all Ethernet centric.  That really is not what you want.

All you need is a basic pair scanner with a TDR for fault location.

Sent from my VS995 using Tapatalk

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Scott AKA "Skyking" Holtzman
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Russell Ault

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #41 on: May 22, 2018, 12:04:51 am »

The problem is those expensive testers are all Ethernet centric.  That really is not what you want.

All you need is a basic pair scanner with a TDR for fault location.

I was hoping you'd chime in! What do you recommend along these lines?

-Russ
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Scott Holtzman

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #42 on: May 22, 2018, 01:10:48 am »

I was hoping you'd chime in! What do you recommend along these lines?

-Russ

The Tripplet LVPRO20 has cable map, fault location and full PoE testing for $200.  It also tests Coax !


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Scott AKA "Skyking" Holtzman
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Tom Bourke

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #43 on: May 22, 2018, 12:30:12 pm »

The Tripplet LVPRO20 has cable map, fault location and full PoE testing for $200.  It also tests Coax !
I have the Byte Brothers version.  Originally bought the 20, upgraded it to 30 for the extra network stuff.  Worth every penny!  Was just on a gig where one of the flown DSMs did not work.  Tests out as a short 20 ft from the end.  Sure enough, right at 20 ft was a kink in the cable.  It would also save me hours and miles of walking during large network deployments.  The simple distance to fault and what pr its on is the best trouble shooting feature I have found in the field.
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Jason Branden

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #44 on: September 13, 2018, 06:17:38 pm »

I thought I'd do a quick update here since I have figured this out and have tested and verified the issue over the course of the summer. I can comfortably say without a DOUBT That the DL32 can NOT be subjected to high magnetic fields without having sync issues.  My suggestion for anyone who has a huge amount of power amplification is to definitely keep their AES50 snakes away from such devices and MOST CERTAINLY do not put them in are around such racks. I have tested this with two separate DL32's and two different m32 boards. Same results. Once I put my production DL32 into the wireless mic rack all issues went away without any further sync issues.   

I had brought a second mixer and DL32 on a few events and played around with it trying to get it to fail in a similar manor. The wheeled extra DL32 I brought had constant sync issues when wheeled near or around the mains. Problems went away at around three feet from the SIDE of the labs or 1 foot from the amp racks at program level. (these amp racks are VERY densely packed)

Anyway, there it is. I'm hoping in the future I can get solid Gauss measurements and come up with an actual threshold but for now I'll just chalk it up to "Keep your sensitive data devices away from crazy high magnetic fields" (Duh!) ::)

A Huge Thanks to all who brainstormed on this tricky one, lots of good insight!


-Jason

« Last Edit: September 13, 2018, 06:45:06 pm by Jason Branden »
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Dan Mortensen

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #45 on: September 14, 2018, 03:28:22 am »

I thought I'd do a quick update here since I have figured this out and have tested and verified the issue over the course of the summer. I can comfortably say without a DOUBT That the DL32 can NOT be subjected to high magnetic fields without having sync issues.  My suggestion for anyone who has a huge amount of power amplification is to definitely keep their AES50 snakes away from such devices and MOST CERTAINLY do not put them in are around such racks. I have tested this with two separate DL32's and two different m32 boards. Same results. Once I put my production DL32 into the wireless mic rack all issues went away without any further sync issues.   

I had brought a second mixer and DL32 on a few events and played around with it trying to get it to fail in a similar manor. The wheeled extra DL32 I brought had constant sync issues when wheeled near or around the mains. Problems went away at around three feet from the SIDE of the labs or 1 foot from the amp racks at program level. (these amp racks are VERY densely packed)

Anyway, there it is. I'm hoping in the future I can get solid Gauss measurements and come up with an actual threshold but for now I'll just chalk it up to "Keep your sensitive data devices away from crazy high magnetic fields" (Duh!) ::)

A Huge Thanks to all who brainstormed on this tricky one, lots of good insight!


-Jason

Nice job, and thank you! You've really advanced the state of our knowledge of how this new stuff works.

After reading through the thread again, I'd like to ask you to revisit the difference in performance between the Midas gear and the Behringer X32/S16 combination, which you said performed flawlessly compared to the Midas.

In your testing and verification, did you confirm again that the S16 etc. had no problem?

Did you try it with the M32 or only all Midas vs. all Behringer?

Also, you say to keep both the DL32 AND the snake away from high magnetic field devices, but you only describe problems when the DL32 itself is in the magnetic fields. What did you experience when the device was away from the magnetic field but the cable was in it? Are the fields too great for the common mode rejection from twisting and balancing transformers (assuming they're there like they are in Ethernet) to handle?

Thanks again!
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Bob Leonard

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #46 on: September 14, 2018, 09:56:04 am »

The Tripplet LVPRO20 has cable map, fault location and full PoE testing for $200.  It also tests Coax !




TDR is key to successful tests of twisted pair cable. Cables that appear good using continuity test devices are often not capable of much more than finding breaks in the cable or poorly attached connectors. A TDR based test set (Time Domain Reflectometer) will pinpoint anomalies at very specific distances.

Substituting the cable with a like cable from the same manufacturer is not always a good test. Quality is the same and results will be similar. Use higher quality cable from American manufacturers (Belden).

Bandwidth may be diminished at lower frequencies.

Put your stage boxes in their own case away from magnetic fields, possibly with a foam cushion under them if you feel vibration is the issue here.

Try running the cable directly from the stage box to the interface, bypassing the spool.

Good luck.
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Jason Branden

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #47 on: September 14, 2018, 10:15:51 am »

Thanks Dan! Yeah, its been an interesting ride on this one! It tested my sanity for sure!


In your testing and verification, did you confirm again that the S16 etc. had no problem?
 
Did you try it with the M32 or only all Midas vs. all Behringer?



Interestingly, I never did have an issue with the S16. Unfortunately I didn't have access to any Behringer gear at the time of testing, but I would certainly love to revisit if the opportunity arises. I was sitting here just now trying to rack my brain on the differences between the setups at the time and I still have no idea what they would of been. Now that I have a good "Control" baseline I could easily test Behringer stuff and see if it has similer issues. I'd also love to also try a DL16 and see if it has the same vulnerability. It could come down to design of the 16 vs 32. 


Also, you say to keep both the DL32 AND the snake away from high magnetic field devices, but you only describe problems when the DL32 itself is in the magnetic fields. What did you experience when the device was away from the magnetic field but the cable was in it? Are the fields too great for the common mode rejection from twisting and balancing transformers (assuming they're there like they are in Ethernet) to handle?

So on that one I should extrapolate a little bit. -admittedly I made the post really quick between doing  few other things.

I completely misspoke when I said that. At the time I was thinking of the stage box when I said "snake" -Not the actual cable, so I didn't communicate that properly. That said, I do spool my snake and when there's extra I leave it on the spool.  Since that last incident I have been keeping it clear of the racks and stacks just as a good practice measure. I didn't test against that however.  -I'm also a little suspect of the panel mount Ethercon connector that was also mounted in the amp rack since their traces arn't shielded on the PCB or otherwise twisted, but that might just be me nitpicking at this point.

I'm hoping as time goes on we'll all learn more and more of the limitations of these systems and with enough collective experience we'll nail it out of the park with a list of general "Do's and Don'ts" OR maybe better put: a list of "Best Practice"  Each event is always a little different but I think if we're all aware of the possibilities we can best mitigate a show from hell ;)

-J

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Taylor Hall

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #48 on: September 14, 2018, 10:38:44 am »

Interestingly, I never did have an issue with the S16. Unfortunately I didn't have access to any Behringer gear at the time of testing, but I would certainly love to revisit if the opportunity arises. I was sitting here just now trying to rack my brain on the differences between the setups at the time and I still have no idea what they would of been. Now that I have a good "Control" baseline I could easily test Behringer stuff and see if it has similer issues. I'd also love to also try a DL16 and see if it has the same vulnerability. It could come down to design of the 16 vs 32. 
If you're good at sussing out board-level components, take a look in the product reviews section, someone did a teardown of the S16 and DL16 and found quite a few differences in the components used in each. It seemed that most of those differences were in the preamp boards, though, and the analog and digital I/O boards seemed almost identical (at least to my eye). If I were a betting man, I'd say that the 32-channel versions would have the same issue unless the additional preamp boards provided some kind of unintentional insulation for EMF.
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Dan Mortensen

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Re: AES50 dropout during subharmonics/anything under sustained 50hz
« Reply #49 on: September 15, 2018, 03:22:25 am »

Now that I have a good "Control" baseline I could easily test Behringer stuff and see if it has similer issues. I'd also love to also try a DL16 and see if it has the same vulnerability. It could come down to design of the 16 vs 32. 

If you want, you could PM me your location. I'm a Behringer dealer and am in pretty good with the local Rep and I bet he knows Reps around the country, so we should be able to get you some Behringer gear to test. If you want.

Based only on the heft of them, I believe the S16 and 32 have steel chassis. I can't find anything about the construction of the DL series; do they have any of the cool looking and expensive anodized and brushed aluminum forming one or more sides of the chassis? I would think they'd be the same as the S series with that ugly old painted steel, but thanks to this thread I'm now aware that the B and M boxes are not identical construction and so chassis construction cannot be taken for granted, I guess.

-I'm also a little suspect of the panel mount Ethercon connector that was also mounted in the amp rack since their traces arn't shielded on the PCB or otherwise twisted, but that might just be me nitpicking at this point.

This could have significance, depending on what you mean by that "Ethercon mounted in the amp rack".

Do you mean a connector that you put there to avoid climbing in the back of the rack each time you connect/disconnect the snake?

Or do you mean the Ethercons on the DL boxes which are its input and jumper?
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