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  #1  
Old 11-21-2019, 08:22 AM
majuro15's Avatar
majuro15 majuro15 is offline
 
Join Date: Feb 2013
Location: Charlotte, NC
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Default Shooting Headset Jack Wires - Chasing Ground Noise

I am getting a static noise in sync my strobes and constant when nav/landing lights are on in my pilot headset jack. I have been able to isolate the noise by controlling my PDA360R via AFS5XXX screens. The back seats can't hear it at all when in Crew mode and the copilot can't hear it at all when it's in ISO mode. The pilot can hear it at all times. That tells me (correct me if I'm wrong) that the issue is with the pilot's jacks.

I do not believe it's lights related as in flight I'm getting a slight alternator whine on the pilot's headset (again, can be isolated to just pilot) as well.

I'm going to finish visually inspecting the wire tonight for nicks or obvious issues, but how can I accurately shoot the wires? I know shield will obviously have continuity with ground, but I'm also getting that with the blue wire for each mic and phone jack. How do you tell if those are good or shorted to ground?

I'm thinking my issue is at the shell connector on the tray as I haven't seen obvious damage to the wire itself and haven't really messed with it since it went in and was tested originally. I did take the backshell apart for the tray during a idiot moment to add a comm swap wire (I should have and wound up putting that comm swap wire to the comm!).

I've searched, but any other advice for just one jack getting static?

Thank you!
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  #2  
Old 11-21-2019, 01:13 PM
BobTurner BobTurner is online now
 
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Noise issues can be tough to track down. Iíd start by examining the pilotís headset jacks. Are the isolating washers intact, jack not touching ground anywhere? Is the braided shield unconnected at the jack, and, again, insulated and not touching anything?
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Old 11-21-2019, 01:34 PM
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Raymo Raymo is offline
 
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Quote:
Originally Posted by majuro15 View Post
The back seats can't hear it at all when in Crew mode and the copilot can't hear it at all when it's in ISO mode.

I've searched, but any other advice for just one jack getting static?
The above statements seem to contradict each other. When in ISO mode, only the pilot should hear anything and in Crew mode, only pilot and co-pilot can hear each other. Sounds like you saying: In normal mode (not crew or ISO) that everyone can hear the noise?
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Old 11-21-2019, 03:44 PM
BobTurner BobTurner is online now
 
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I would say that those statements are consistent with the noise source being between the audio panel and the radios.
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  #5  
Old 11-21-2019, 04:30 PM
KatanaPilot KatanaPilot is offline
 
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Default ZipTips

Do you have Aveo ZipTips by chance? I know the folks at Synergy out in Eugene are having fits with noise from ZipTips on a customer airplane. If so, it seems to be a common thread.

If you get it resolved, please PM me with the solution and I'll forward it to Synergy too.
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  #6  
Old 11-21-2019, 04:32 PM
Flash Flash is offline
 
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I just had this happen in my 8. It ended up being the ground in the pilot transmitter jack. The ground wire back to the rack had a break and the transmitter jack was touching the cover and aircraft noise was coming through. I used the ground to the backseat transmitter to the tray for a good ground and insulated the connection so it wasn't touching the cover. with your noise, I would have to believe somewhere on your pilot jacks or their wires, your ground it contacting the frame.
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Old 11-22-2019, 07:44 AM
Rainier Lamers Rainier Lamers is offline
 
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Location: Somerset West
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Many years of assisting customers with audio problems related to intercom systems, headsets, radios have resulted in some experience.

However, recently, I struck gold, quite by accident.

In the past I used to recommend simple small audio transformers to break the ground loop issue. You can get them inexpensive - typically the 1:1 600 ohm types often used in phone line systems.

Then I started using a Bourns SMD type (SM-LP-5001 - you can get from Digikey in small quantities) as I wanted something smaller you can easily incorporate in an audio cable with a bit of shrink sleeving over it. This thing worked very well indeed but I noticed it was particularly effective with RF induced problems - normally the audio transformers tend to just couple RF without much advantage here. This one effectively blocks it totally.

Even better - you can wire it as common mode choke into headset microphone feeds (it's small and can be wired right into the mic socket). In this mode it conducts DC so the MIC still gets its bias current, audio passes as differential signal unaffected, any common mode noise is attenuated and even better - RF is blocked as the core material handles it quite nicely.

It's the solution to pesky RF feedback problems in compromised installations.

I devoted a chapter to how to use them between intercom systems COM outputs and radio MIC inputs as well as into standalone radio/intercom systems into the headset MIC feeds in the A16 manual you can get from our website. The manual is dedicated to out A16 but the solution is applicable to any make of intercom system and radio so if you have some issues in this area - give it a read.

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Old 11-22-2019, 08:48 AM
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majuro15 majuro15 is offline
 
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Quote:
Originally Posted by Raymo View Post
The above statements seem to contradict each other. When in ISO mode, only the pilot should hear anything and in Crew mode, only pilot and co-pilot can hear each other. Sounds like you saying: In normal mode (not crew or ISO) that everyone can hear the noise?
My remote audio panel doesn't work like that. In ISO mode, the pilot is isolated and has no side tone unless transmitting on a radio. The three other seats are all intercom connected and cannot hear radio traffic at all.

In Crew mode, the backseaters are intercom only and the front seaters are intercom between themselves and radio.
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  #9  
Old 11-22-2019, 08:49 AM
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majuro15 majuro15 is offline
 
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Quote:
Originally Posted by KatanaPilot View Post
Do you have Aveo ZipTips by chance? I know the folks at Synergy out in Eugene are having fits with noise from ZipTips on a customer airplane. If so, it seems to be a common thread.

If you get it resolved, please PM me with the solution and I'll forward it to Synergy too.
I do have ZipTips, but tested them a while ago and had zero noise. It's also not consistent across all headset jacks, which leads me to believe it's an audio wiring issue, not related to the ZipTips.
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  #10  
Old 11-22-2019, 08:55 AM
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majuro15 majuro15 is offline
 
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I have confirmed the jacks are isolated with washers properly and ironically the jacks I have it narrowed down to are mounted in a plastic material anyway, not CF or metal. Either way, the isolation washers are correct on all four jacks.

The shields are properly terminated at the jacks but I haven't verified the tray connector yet. I haven't been able to visually trace the wire its entire path yet to verify no nicks, so that's this weekend too.

I have a good feeling I messed up something at the backshell connector on the tray so I'm going to dive into it tomorrow and see. If nothing else, I can run a new wire and see what that does.

I did find out that I need to unplug the jack wires from the audio panel (of course) to pin them and check continuity. That's the plan for tomorrow.
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