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Author Topic: Static Cat5e STP????  (Read 2833 times)

dave milton

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Re: Static Cat5e STP????
« Reply #10 on: March 14, 2019, 10:36:25 am »

So, I'm pretty certain I've identified the culprit. 
See this thread (which many of you on this one participated in): https://forums.prosoundweb.com/index.php?topic=169141.30  beginning at post #33.

My cable is an EliteCore with CS45 Converta-Shell connectors.  Which means no continuity at the shells, which is specifically a no-no when used with an X32.  All explained pretty clearly in that thread.

BUT!!!!!.......what I still don't get is why I've never had this problem in any other install, why I "fixed" this problem by moving the mix-position and cable run to a different place, and why stepping in that little zone specifically was the only thing that made the problem manifest.  Also, in my trouble shooting, I shook/wiggled the connections on both ends a few times....why didn't I get any pops then? 

Some more info on that "zone":
* The quality of the steps didn't seem to matter.  Meaning that it wasn't just when someone stepped hard or heavily.  Sometimes in fact it was just a very soft/gentle step.  I really don't think any mechanical shaking or flexing came into play.
* The steps were sometimes on wood, sometimes on carpet. 

In answer to some of the last questions:
* The speakers and SD16s were plugged into a common circuit down by the stage.  The console was plugged into another circuit near the back of the venue.....the same one for both positions.
* The replacement cable was of the same type (with CS45 connectors), and I didn't try reversing the connection.
* As far as the carpet/wood/cable run setup, picture this:  The seating on the main floor of the venue had one big center section of rows, with aisles running along either side, and a side section of rows on either side of those.  The floor itself is wood.  The aisles are carpeted.  Then there is a sort of "dance-floor" or "orchestra-pit" section immediately in front of the stage, which is wood.  My mix position was in the main section of seats about 2/3's of the way back from the stage, right next to one of the aisles.  That snake cable ran along the aisle, on the wooden floor but right next to the edge of the carpet, for about 50-60', then across the wooden "dance-floor" for another 10-20'.  The trouble-zone was right at the end of that aisle as it opened onto the "dance-floor", about half on the carpet and half on the wood.
* This was really the only spot that had this combo of wood/carpet.
* In the new position, the cable was not near any carpet

thanks for all your help on this,
d.
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Russell Ault

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Re: Static Cat5e STP????
« Reply #11 on: March 14, 2019, 01:46:36 pm »

So, I'm pretty certain I've identified the culprit.  [...]

My cable is an EliteCore with CS45 Converta-Shell connectors.  Which means no continuity at the shells, which is specifically a no-no when used with an X32.  All explained pretty clearly in that thread.

BUT!!!!!.......what I still don't get is why I've never had this problem in any other install, why I "fixed" this problem by moving the mix-position and cable run to a different place, and why stepping in that little zone specifically was the only thing that made the problem manifest.  Also, in my trouble shooting, I shook/wiggled the connections on both ends a few times....why didn't I get any pops then? 

[...]

ESD-related issues are some of the most intermittent in you'll ever run into. Before we all knew better, I once watched as a small change in humidity took an X32 + stagebox rig (using bog standard networking cable) from perfectly stable to "audio drops every couple minutes".

It can help to remember that static electricity will travel through things that we would normally thing of as insulators (like carpet). I once worked with a recording setup where any time anyone stepped into the carpeted aisles of a venue the recording would click, even if they were on the other side of the room (which is when I discovered that some mic cable assembly manufacturers inexplicably tie their XLR shells to ground).

Wiggling the connectors wouldn't have made a difference (unless that motion was somehow capable of producing a static charge, which I'd sure hope it's not!), especially since the connector shells weren't tied to the shields anyway. With ESD the problem is not that the connection is intermittent (which is normally why we'd wiggle connectors), the problem is that there isn't a safe path for static discharge (when it happens, if it happens) to go.

Basically, the reason you haven't had problems before with this setup (and were able to get through the day by changing the cable routing) is because you're lucky. :) If you want to be sure it's going to work, make sure that there is EtherCON shell-to-shell continuity on all cables used for AES50 in your system (including between two S16s in the same rack). Doing anything else is opening the door to trouble.

-Russ
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Dan Mortensen

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Re: Static Cat5e STP????
« Reply #12 on: March 14, 2019, 05:04:06 pm »

So, I'm pretty certain I've identified the culprit. 
See this thread (which many of you on this one participated in): https://forums.prosoundweb.com/index.php?topic=169141.30  beginning at post #33.

My cable is an EliteCore with CS45 Converta-Shell connectors.  Which means no continuity at the shells, which is specifically a no-no when used with an X32.  All explained pretty clearly in that thread.

BUT!!!!!.......what I still don't get is why I've never had this problem in any other install, why I "fixed" this problem by moving the mix-position and cable run to a different place, and why stepping in that little zone specifically was the only thing that made the problem manifest.  Also, in my trouble shooting, I shook/wiggled the connections on both ends a few times....why didn't I get any pops then? 

Thanks for the good news, Dave!

Although I participated in that thread (and am still waiting for the flame war as a result), the Converta Shell didn't register with me and I've forgotten even looking at it at the time, since it's of no interest. I just left a review of it on Amazon, though; we'll see if they print it.

Definitely you need to replace those shells with Neutriks, which should be about a five minute operation. Try Audiopile for them rather than Amazon, although if you are a Prime Member that may be cheaper than paying shipping depending on how many you buy.

Still, even if that's the culprit, that means that a static spark is not only jumping 2-5 feet (from carpet to snake in the middle) but it is then jumping through the cable jacket to travel to both ends of the cable to get in where those Converta shells are located.

I'm having a hard time comprehending that. 2' spark jump is Tesla coil range, not foot shuffling range.

Even if the spark source was touching the cable, isn't the jacket there to prevent that?

Question for anyone:

When a jacket is rated at 300 volts or whatever, does that mean a larger voltage can pass through it? Static is in the thousands (tens? Wikipedia says 4000-35000) of volts but not much amps.

If so, then I guess that explains something else that we need to be aware of, but I still don't get the 2' gap jump.
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Dan Mortensen

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Re: Static Cat5e STP????
« Reply #13 on: March 14, 2019, 05:12:45 pm »

Before we all knew better, I once watched as a small change in humidity took an X32 + stagebox rig (using bog standard networking cable) from perfectly stable to "audio drops every couple minutes".

Could you please elaborate on this? How you know it was humidity, and if you know what the no-problem range was and what the problem range was? Were you using a hygrometer? Do you do that at all your gigs?

Sound is affected by humidity in strange non-linear ways, but I didn't realize that anything short of deluge would affect electrical continuity/data transmission.

Also, "Bog standard networking cable" means "no Ethercons/not shielded"?

Basically, the reason you haven't had problems before with this setup (and were able to get through the day by changing the cable routing) is because you're lucky. :)

I've found that luck beats skill almost every time, and rely upon it in my work, too. (Mostly serious.)
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Russell Ault

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Re: Static Cat5e STP????
« Reply #14 on: March 14, 2019, 06:29:54 pm »

Still, even if that's the culprit, that means that a static spark is not only jumping 2-5 feet (from carpet to snake in the middle) but it is then jumping through the cable jacket to travel to both ends of the cable to get in where those Converta shells are located.

I'm having a hard time comprehending that. 2' spark jump is Tesla coil range, not foot shuffling range.

Even if the spark source was touching the cable, isn't the jacket there to prevent that?

Question for anyone:

When a jacket is rated at 300 volts or whatever, does that mean a larger voltage can pass through it? Static is in the thousands (tens? Wikipedia says 4000-35000) of volts but not much amps.

If so, then I guess that explains something else that we need to be aware of, but I still don't get the 2' gap jump.

Everything has a breakdown voltage, above which an insulator becomes a conductor. Typically the breakdown voltage for a cable is a significant multiple of its rated voltage, but it might be possible for static charges to reach those voltages (depending on the insulation's actual breakdown voltage and the charges involved). As for the distance, a lot of carpet these days is manufactured with added conductive fibres (ironically in an effort to reduce static buildup), so it's also possible for a static charge to pass through a couple feet of carpet (or significantly further, which I've run into).

Could you please elaborate on this? How you know it was humidity, and if you know what the no-problem range was and what the problem range was? Were you using a hygrometer? Do you do that at all your gigs?

Sound is affected by humidity in strange non-linear ways, but I didn't realize that anything short of deluge would affect electrical continuity/data transmission.

Humidity gives air free ions; a static charge will build up more readily as humidity drops because it can't dissipate into the air as readily. This increased charge increases the likelihood of ESD-related problems. The air here is quite dry to begin with, and air handling systems tend to make the air even drier. This was several years ago now (again, before the ESD problems with the X32 were well understood), so my recollection isn't perfect; the point was more about how there are many factors that will effect ESD, which is why problems are best avoided where possible (and best practises are so important).

Also, "Bog standard networking cable" means "no Ethercons/not shielded"?

Yup. Learned my lesson the hard way.

-Russ
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Dan Mortensen

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Re: Static Cat5e STP????
« Reply #15 on: March 14, 2019, 07:52:37 pm »

As for the distance, a lot of carpet these days is manufactured with added conductive fibres (ironically in an effort to reduce static buildup), so it's also possible for a static charge to pass through a couple feet of carpet (or significantly further, which I've run into).

Yes, but if I understood what Dave was saying, there was 2-5' of wood floor separating the carpet from the snake. That's a long jump.

Thanks for the other info.
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Tim McCulloch

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Re: Static Cat5e STP????
« Reply #16 on: March 15, 2019, 10:10:06 am »

A 300V rating on a CATegory cable jacket is for Code compliance.  With it you can run the cable in the same tray or conduit as same-rated electrical cables.
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Taylor Hall

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Re: Static Cat5e STP????
« Reply #17 on: March 15, 2019, 10:28:17 am »

Yes, but if I understood what Dave was saying, there was 2-5' of wood floor separating the carpet from the snake. That's a long jump.

Thanks for the other info.
But certainly not outside the realm of possibility. The speakers connected to the receptionists' computer at my old job would pop and crackle any time someone took off their jacket in the waiting area, and that was the same distance if not more away with the added bonus of being separated by the wooden facade of their desk.

Foot traffic on the carpeted area might have built up enough of a charge that someone walking close enough to the cabling would be enough to trigger a discharge to the cabling if an insufficient grounding source wasn't available anywhere else in the room. Definitely all conjecture on my part, but I'll happily eat crow for someone with a degree in this type stuff :P
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lindsay Dean

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Re: Static Cat5e STP????
« Reply #18 on: March 15, 2019, 10:56:41 am »

I found this on an earlier post solution

Static discharge into Cat 5e can cause audio gremlins in the X32. The bonding of the shell of an ethercon connector is key to avoiding problems. It may be less of an issue with installed cable because the cable isn't laying on carpet, getting stepped on, dragged, and so on. You could try using the installed cable along with shielded, ethercon jumpers from the wall jacks Of course, it'll work perfectly until that really critical show.
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Kevin Maxwell

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Re: Static Cat5e STP????
« Reply #19 on: March 16, 2019, 12:20:31 pm »

Sometimes failures arenít just one thing but a combination of things. And sometimes there isnít anything that you can do about static other than eliminating it at the source. Regularly using Static Guard spray has been the only way that I have been able to eliminate static in a few churches that I have dealt with. One of them if you walked on the carpet and touched wood, yes I said touching wood, you would get a static shock that sent a bang into the sound system. No amount of grounding could fix that problem. This was a completely analog system.
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