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Thread: Data cable part 471-question 91

  1. #41
    That does seems to be consistent with their options available for the chassis connections (and granted, that may seem vague until you stop to consider that they place the burden of establish the connector-to-panel termination choice back on the device manufacturers and system integrators. There are options (or choices) in etherCON receptacles that provide for removing the connector-to-chassis (or panel) termination.

    Consider my X32-RACK integration. I have an X32-RACK and 2 S16 Digital snakes in the same rack with an analog stage snake panel (muck like the Ram-Tech STGBX-54) and some other rackmount components, including an I/O panel for the rear connections from the X32-RACK. All the panel-mounted (chassis) connectors are terminated to the same chassis ground through the panels and rack rails. If for some reason I wanted to remove the shield-to-chassis terminations for the etherCON chassis connectors, there are tabs on those connectors I could remove on some of the etherCON receptacles that Neutrik offers. Granted, there are some Neutrik connectors that do not have that option in which case I would need to choose a different Neutrik receptacle to provide such isolation. In my case I have chosen not to isolate the shield-to-chassis isolation so all the tabs are in place.

    So what Neutrik is saying is that the manufacturer of the electronic components (in our case Behringer) chooses just how they want to accomplish the particular terminations.

    So what that means for us is rather straight-forward. In the U-tube (sp?) videos of the X32 and the S16 where they are not electrically bonded via chassis ground, you would expect to see that electrostatic discharge to be a concern and the result of those "tests" illustrating channel drop-out are 100% correct. In those integrations of rack-mounted devices, such as an X32-RACK and S16s physically mounted in the same rack (and on the same rack rails), I would expect to see that the electrostatic concerns would already be taken care of via the chassis terminations made through that rack rail. In the case of the X32-RACK and the S16, I believe that we would need to ask Behringer engineers specifically which etherCON they used in the manufacture of those devices and how they handled the terminations at those chassis devices. From the "tests" we have seen, it makes sense that they do rely on the shield-to-chassis termination on the S16 and the X32-RACK. Since the X32-FULL (?) is not rack-mounted, that console would seem to need to rely on "shield-to-termination" using the shield-to-chassis termination provided by the physical connection of the shielded RJ45 jack with the etherCON carrier. Most importantly, it will always be the drain wire that provides the physical bonding, and not the etherCON carrier.

    That gets back to the need for the etherCON carrier (NE8MC or NE8MC-1). I still believe that using the etherCON carrier is still to provide a more reliable connection that cannot be pulled out as easily and not that it provides the shield connection--the combination of shielded Cat5e and the shielded RJ45 connector provides that. In the case of the S16, the answer could be as simple as the shield-to-chassis termination might be removed on that device which is why the use of the etherCON carrier connected to that device provides the better electrostatic shield. Again, in those cases where the X32-RACK and the S16s are located on the same rack rail, using the etherCON carrier for INTERNAL rack wiring would not be necessary. Again, I could be off-base but I really don't think so.

    Sorry about the long-windedness.

  2. #42
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    We had already figured out that the ethercon shell does not provide the ground connection.

    However, if you apply a high voltage (as in an electrostatic discharge) to the chassis of the device (X32 or S16), the chassis has a high voltage with respect to the signal wires, because there is a gap between the wires and the case on the underside of the RJ45-plug where it enters the chassis. These gaps are what you try to eliminate with electromagnetic shielding, and putting a grounded ethercon shell in there means that the high voltage discharge can no longer reach the signal wires as it is shielded by the ethercon shell in the senistive area where it enters the housing.

    For that to work, the Ethercon shell must be grounded, and because the chassis connector doesn't ground it, it must be grounded to the RJ45 jack shield. The Neutrilk response does not clarify how this grounding is achieved, or if it is intended at all!
    Think of this board as a Swiss Army Mixer. --Glenn Adams

  3. #43
    They are saying there is no contact, however I have contact from my ne8mc-1's end to end. It IS happening one way or another, I have a f/u question about this specifically so we will see what said next.

  4. #44
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    Quote Originally Posted by gary higgins View Post
    They are saying there is no contact, however I have contact from my ne8mc-1's end to end. It IS happening one way or another, I have a f/u question about this specifically so we will see what said next.
    Yes. Neutrik is simply saying that there is no contact for the Ethercon to the chassis (which could be confirmed by inserting an empty ethercon shell),and it is good to have that confirmed by Neutrik explicitly, but we know there is contact from it to the cable shield (and then through the RJ-45 jack to the chassis, if wired correctly), and we also know that it is necessary to protect against static discharges to the mixer or S16 chassis.
    Think of this board as a Swiss Army Mixer. --Glenn Adams

  5. #45
    Quote Originally Posted by Michael Mendelsohn View Post
    Yes. Neutrik is simply saying that there is no contact for the Ethercon to the chassis (which could be confirmed by inserting an empty ethercon shell),and it is good to have that confirmed by Neutrik explicitly, but we know there is contact from it to the cable shield (and then through the RJ-45 jack to the chassis, if wired correctly), and we also know that it is necessary to protect against static discharges to the mixer or S16 chassis.
    They are actually saying there is no electrical interaction in any regard from the cable and rj45 to the ne8mc-1. It only provides rugged mechanical protection. I have 2 more responses from them to post in a few. Still leaves me scratching my head.

  6. #46
    Response #2:

    Dear Gary,
    NE8MC is irrelevant to drain wire continuity. As you will see from the assembly instructions, NE8MC never interacts with the wires in the cable or with the RJ45 connector. It simply shrouds those wires and that RJ45 in a rugged, locking metal shell.

    In regards to the cable and RJ45 connectorization that you choose, yes: it is typically advantageous to have shield/drain continuity in your digital audio Ethernet cables.

    Best wishes,
    - Fred

    My f/u question:

    Sorry to be so thick (also my last question) but I'm using the shielded rj45's which are metal covered and make contact with the drain wire/sheath, do they not touch the case of the ne8mc anywhere as it looks like they make contact to the channel? Or should this be avoided. It is happening with my cables, there is continuity from the ne8mc-1. Thanks for helping out!

    Response #3

    They do not electrically interact with the Neutrik NE8MC.

    Thanks,
    Fred

  7. #47
    ? Boing ? Bonk ? Clank.....I can only come to 2 conclusions. 1. My cables are not connected properly within the NE8MC...back to the drawing boards...and 2. Continuity from NE8MC to NE8MC is not needed to have a good shielded AES50 connection. Neither of the 2 I am quite ready to embrace....

  8. #48
    Ok, my last words on this...After some more examination and a few more tests I have concluded that the info I got back from Neutrik is not exactly accurate...and maybe just plain wrong. There is no way a shielded rj45 does not contact the NE8MC when assembled. I even went so far as to put an unused shielded rj45 into the NE8MC and test for continuity. There is without the slightest of doubt, contact. If the shielded cable is properly connected to the rj45, then the foil shield and/or drain wire is in contact with the rj45 shield and continuity takes place from the outer shell, end to end once the rj45 is placed in the NE8MC etherCON case. If you trim back the foil and cut the drain wire on one end this stops, you can demonstrate this again and again...and again. I am 100% sure this IS happening. I would also add that if Neutrik really did not want any interaction from their ethercon carrier they would have designed the inner channel to be made from a non conductive material and isolated such that it would not matter if the shielded rj45 touched it or not. Since this is NOT the case, I'm left to conclude the contact is intended and neccesary for proper shielding. Others can conclude what they will.

  9. #49
    Perhaps they misunderstood your question. As Michael points out, when using only shielded Cat5e with shielded RJ45 plugs, our problem with EMI is that it is injected into the data connection through the unprotected space between the RJ45 plug and the etherCON receptacle. I have always used NE8MCs for my external wiring and I have since added etherCON carriers to all the shielded AES50 connections inside my racks to ensure that there is no point of entry for EMI.

    Neutrik's statement that the etherCON connector is irrelevant to the electrical continuity of the shield is the same place I went awry. Not only should we be concerned with the electrical integrity of the shield but we also need to take into account the physical nature (or barrier) of the shield itself. There is normally an electrical connection (or bonding) between the shielded RJ45 jack and the etherCON carrier that takes place inside the etherCON receptacle and when the etherCON carrier is placed into that receptacle, the metal portion of the carrier shrouds the unprotected portion of the shielded RJ45 plug. In that the shield is maintained in the cable by the use of shielded Cat5e with shielded RJ45 jacks, the etherCON carrier is irrelevant to maintaining that integrity. Then again, as Michael points out, we are also concerned with the physical barrier put in place by the etherCON carrier which Neutrik did not take into account in their statement.

  10. #50
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    When talking about shields, I'd call the ethercon shell an electrical barrier (especially when it's grounded). It is a mechanical barrier to having a loose RJ45 connector stepped on or the contacts in it directly touching a (possibly statically charged) carpet.
    Think of this board as a Swiss Army Mixer. --Glenn Adams

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