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[Mike Sokol]

FWIW I've had an X32 and S16 knowingly on different phase legs without any issues whatsoever.

Correct. Being on a different phase leg will not cause any kind of ground loop hum or other audio artifacts. That's misinformation that should be purged from the technical community. 

[Douglas R. Allen]

Rereading that thread in which I was an active participant does not give any allegations of blown or damaged AES50 ports, and the problems that were documented had nothing to do with stage and foh being on different grounds, although there was speculation but not proof of what would happen in that case.

Reread it again, please, and see if it makes better sense this time.

That said, Art's advice is good. I've taken to using tiny and cheap UPS's and haven't noticed any difference in practice from using the big heavy expensive UPS's that I also still have. FWIW.

Post No. 2.    There are isolation transformers you can use if grounding becomes an issue.  "Why I asked about 1 to 1 transformers"

      No. 6.     >However, if you use a shielded cable with shielded connectors you will connect both chassis together via the shield. By breaking the shield you'll disconnect the grounding between the devices.

You also need to consider what you connect to your s16 and your x32. Any device that isn't ground-lifted may become a cause of a ground loop. Even racks can cause ground loops if you have a bad day.<   

      Does breaking the ground to the mixer with 1 to 1 120v transformer at foh also break the ground between desk and stage box? If the board is Lifted then the only ground would come from stage to the desk via the shielded connectors. Is this better or worse than not lifting (if that is correct term ) with a 1 to 1 transformer? Would this cause static buildup that seems to be taking out AES50 ports?  I see more an more that this is a fault of UTP and other incorrect Cat wire not the setup I'm using. Maybe I should just use it as is.
 
I'm new to the AES50 system so I want the correct setup. I'm currently using the correct wire but want to have what is required to be the safest possible.
Basic question is if I end up with FOH not on stage power and with no way to test prior to the show would I continue to find power at the desk area and use the current setup or should I go with a 1 to 1 transformer and a UPS just for safety sake or as others have stated continue to run power to FOH? ( some say cat and 120 tied together is wrong but I'm not so sure either ) You have to remember I am in an area where you still can find only 2 prong outlets. No way to plug in a standard 3 prong plug.

Thanks everyone! Getting the correct information I need.

Douglas R. Allen

[Tim McCulloch]

Post No. 2.    There are isolation transformers you can use if grounding becomes an issue.  "Why I asked about 1 to 1 transformers"

      No. 6.     >However, if you use a shielded cable with shielded connectors you will connect both chassis together via the shield. By breaking the shield you'll disconnect the grounding between the devices.

You also need to consider what you connect to your s16 and your x32. Any device that isn't ground-lifted may become a cause of a ground loop. Even racks can cause ground loops if you have a bad day.<   

      Does breaking the ground to the mixer with 1 to 1 120v transformer at foh also break the ground between desk and stage box? If the board is Lifted then the only ground would come from stage to the desk via the shielded connectors. Is this better or worse than not lifting (if that is correct term ) with a 1 to 1 transformer? Would this cause static buildup that seems to be taking out AES50 ports?  I see more an more that this is a fault of UTP and other incorrect Cat wire not the setup I'm using. Maybe I should just use it as is.
 
I'm new to the AES50 system so I want the correct setup. I'm currently using the correct wire but want to have what is required to be the safest possible.
Basic question is if I end up with FOH not on stage power and with no way to test prior to the show would I continue to find power at the desk area and use the current setup or should I go with a 1 to 1 transformer and a UPS just for safety sake or as others have stated continue to run power to FOH? ( some say cat and 120 tied together is wrong but I'm not so sure either ) You have to remember I am in an area where you still can find only 2 prong outlets. No way to plug in a standard 3 prong plug.

Thanks everyone! Getting the correct information I need.

Douglas R. Allen

You likely need to do NOTHING based on the lack of complaints or reports of the failure (s) you describe.  I'm not sure where you heard this stuff but after 4 years and 500,000 X32 in the wild and probably 100,000 stage boxes of both brands, yours is the only mention.

[Geoff Doane]

Does breaking the ground to the mixer with 1 to 1 120v transformer at foh also break the ground between desk and stage box? If the board is Lifted then the only ground would come from stage to the desk via the shielded connectors. Is this better or worse than not lifting (if that is correct term ) with a 1 to 1 transformer? Would this cause static buildup that seems to be taking out AES50 ports?  I see more an more that this is a fault of UTP and other incorrect Cat wire not the setup I'm using. Maybe I should just use it as is.

From what I can tell in that link you supplied, the Tripp Lite isolation transformer does NOT lift the ground to the load(s).  I doubt it would be able to get safety certification if it did.  It does connect the secondary neutral to ground in order to avoid "noise" on the neutral coming in, which may reduce some kinds of line noise, and that is perfectly acceptable.

Has anybody actually tested the stability of the X32/S16 when the shield of STP CAT5 or CAT6 is only connected at one end?  Maybe inserting a ground lift (in the AES50 link) is a valid fix if the cable otherwise causes a ground loop.  BTW, it seems like installing UTP cable in a grounded conduit would be a way around the problem, but not much good for portable installations.

GTD

[Tim McCulloch]

From what I can tell in that link you supplied, the Tripp Lite isolation transformer does NOT lift the ground to the load(s).  I doubt it would be able to get safety certification if it did.  It does connect the secondary neutral to ground in order to avoid "noise" on the neutral coming in, which may reduce some kinds of line noise, and that is perfectly acceptable.

Has anybody actually tested the stability of the X32/S16 when the shield of STP CAT5 or CAT6 is only connected at one end?  Maybe inserting a ground lift (in the AES50 link) is a valid fix if the cable otherwise causes a ground loop.  BTW, it seems like installing UTP cable in a grounded conduit would be a way around the problem, but not much good for portable installations.

GTD

Dropping the CAT5 shield at either end will effectively defeat the necessary and intended grounding scheme.  If you like pops and pauses while sync is re-established, go ahead.

I STRONGLY urge everyone here that doubts or questions to go back and read Dan Mortensen's posts and follow up with the youtube videos.

I'm at a loss as to why this has become such an issue as there has yet to be a verifiable destruction of hardware for the reasons cited by Doug.  If you don't buy into the *requirement* of STP CAT cable with bonded-to-shell Ethercons, fine, you don't have to believe in gravity, either.

A documented and verified case of this failure needs to be presented.
 

[Douglas R. Allen]

Dropping the CAT5 shield at either end will effectively defeat the necessary and intended grounding scheme.  If you like pops and pauses while sync is re-established, go ahead.

I STRONGLY urge everyone here that doubts or questions to go back and read Dan Mortensen's posts and follow up with the youtube videos.

I'm at a loss as to why this has become such an issue as there has yet to be a verifiable destruction of hardware for the reasons cited by Doug.  If you don't buy into the *requirement* of STP CAT cable with bonded-to-shell Ethercons, fine, you don't have to believe in gravity, either.

A documented and verified case of this failure needs to be presented.

i my self did fry 3 aes50 ports back in the day where specs said just anny cat5 will do. and i know of a lot more fryed aes50 ports.
then sudently specs said shieldet cat5 with conection between shells, and the last 3 years or so i havnt fryed one single aes port in the many desks i work with.

From behringer x32 groups post.  Again I'm using correct cable but I  wondered if using a 1 to 1 transformer effected the shield ground and in effect made cat5e not work as it should.  Should a person take the time to Google x32/m32 aes50 failure and also go on the facebooks m32/x32 many user groups you will see many post where aes ports have been damaged using incorrect cat5 cables and or setups.  I was looking for answers for the correct setup and/or a better way and if what I had in mind was a good idea or "could make things worse." I see now I have less to worry about.  I have read post on damaged aes50 ports.  Its out there. I wouldn't of asked the questions had it been otherwise. Now I have my answer. It is much (much) less an issue with the proper cable.

Douglas R. Allen

[Jonathan Betts]

I was warned about the possibility of blown aes ports when I purchased my Pro 1 and DL 153. The issue they said would only happen if running console and stage rack from different grounds. The work around I was told was to use a Ethercon NE8ff and run non shielded cat5 from the connector to console aes port. 

[Mike Sokol]

I was warned about the possibility of blown aes ports when I purchased my Pro 1 and DL 153. The issue they said would only happen if running console and stage rack from different grounds. The work around I was told was to use a Ethercon NE8ff and run non shielded cat5 from the connector to console aes port.

That seems backwards. Without a terminated shield on the CAT5 line, there's the possibility of quite a large differential voltage to exist between the console and digital snake. Now normally this might be only 1 or 2 volts, and only if someone does something silly in the power distro like swapped neutrals and grounds in an outlet feeding your system. Even in that case it will probably still be OK. But with a lifted CAT5 shield, if you get one of your boxes plugged into an outlet with a hot ground from something like an RPBG (Reverse Polarity Bootleg Ground), then it's game over for your AES50 ports. A properly terminated CAT5 STP cable will still be the safest connection, since it will attempt to keep the chassis of both your console and the digital stage box at the same voltage potential.

[Jonathan Betts]

Midas Pro recommends UN shielded cat 5 cable. All my cable is high quality shielded,  with RJ 45 connectors. I use short,  UN shielded jumpers at each end of the snake.

So this is not correct and should be avoided?

[Tim McCulloch]

Midas Pro recommends UN shielded cat 5 cable. All my cable is high quality shielded,  with RJ 45 connectors. I use short,  UN shielded jumpers at each end of the snake.

So this is not correct and should be avoided?

The Pro Series consoles and DL1xx, DL2xx, DL3xx and DL4xx do not require STP and will work fine with UTP.

There is apparently a difference in either chipset or physical grounding scheme that makes these products much less vulnerable to ESD problems.

[ProSoundWeb Community]