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SAC · 10th April 2010

For balanced lines/connections, follow the Gruschka "How To Test For Pin 1 Problems" procedure. How to Test for the Pin-1 Problem, by Mary C. Gruszka

This can be easily made with a standard wall-wart transformer and an appropriate light socket. Just verify the ratings.

I think I may have neglected to provide the link to this 2nd of the 3 excellent Mary Gruschka articles regarding Pin ! troubleshooting. (oops!) (Since fixed) This will specifically help with the balanced line troubleshooting!

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The rest are simply a few additional aspects noting that problems can originate in one place and become apparent in another!

"Barring fixing the equipment itself, take care in cable interconnection. Find a way to connect the shield of the signal cable to the equipment chassis instead of through the connector. This means breaking out the shield from the cable connector and finding a convenient place on the chassis, ideally near the mating connector, for a chassis connection. You may need to scrape paint and add a toothed washer beneath a screw to get a solid connection." Gruschka. Resolving Pin 1 Problems (but FOLLOW the procedure step by step! Do NOT use this out of context!!!!)

Oh, and if folks are using XLR connectors, I cannot recommend the Neutrik EMC-XLR - NC3FXX-EMC series enough that feature the addition of an annular capacitor to avoid the issues related to the pin 1 issue.

Oh...and I may as well mention to verify the integrity of the video paths as well, which can definitely cause audio issue as well.

"This brings up the point that pin-1 problems may not always manifest themselves at audio frequencies. If the shield is connected to the chassis by a small length of wire or trace, it may act as an antenna at RF frequencies, but not cause problems in the audio range. Also, pin-1 problems could cause the internal clock or other types of noise to be radiated outside the chassis and be a potential source of interference to other pieces of gear. This can easily snowball.

I've used analog-balanced interconnections for the examples presented here, but pin-1 problems can lurk in unbalanced inputs and outputs, as well as in digital equipment.

Although induced noise may not be heard directly in digital equipment with pin-1 problems, that noise could be enough to prevent the digital signal from being received/decoded properly somewhere else in the signal chain."

10th April 2010	#27
SAC Registered User Joined: Dec 2009 Posts: 2,622	For *balanced* lines/connections, follow the Gruschka "How To Test For Pin 1 Problems" procedure. How to Test for the Pin-1 Problem, by Mary C. Gruszka This can be easily made with a standard wall-wart transformer and an appropriate light socket. Just verify the ratings. I think I may have neglected to provide the link to this 2nd of the 3 excellent Mary Gruschka articles regarding Pin ! troubleshooting. (oops!) (Since fixed) This will specifically help with the balanced line troubleshooting! ---------------------------------------------- The rest are simply a few additional aspects noting that problems can originate in one place and become apparent in another! "Barring fixing the equipment itself, take care in cable interconnection. Find a way to connect the shield of the signal cable to the equipment chassis instead of through the connector. This means breaking out the shield from the cable connector and finding a convenient place on the chassis, ideally near the mating connector, for a chassis connection. You may need to scrape paint and add a toothed washer beneath a screw to get a solid connection." Gruschka. Resolving Pin 1 Problems (but FOLLOW the procedure step by step! Do NOT use this out of context!!!!) Oh, and if folks are using XLR connectors, I cannot recommend the Neutrik EMC-XLR - NC3FXX-EMC series enough that feature the addition of an annular capacitor to avoid the issues related to the pin 1 issue. Oh...and I may as well mention to verify the integrity of the video paths as well, which can definitely cause audio issue as well. "This brings up the point that pin-1 problems may not always manifest themselves at audio frequencies. If the shield is connected to the chassis by a small length of wire or trace, it may act as an antenna at RF frequencies, but not cause problems in the audio range. Also, pin-1 problems could cause the internal clock or other types of noise to be radiated outside the chassis and be a potential source of interference to other pieces of gear. This can easily snowball. I've used analog-balanced interconnections for the examples presented here, but pin-1 problems can lurk in unbalanced inputs and outputs, as well as in digital equipment. Although induced noise may not be heard directly in digital equipment with pin-1 problems, that noise could be enough to prevent the digital signal from being received/decoded properly somewhere else in the signal chain."