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Headset/Mic jack wiring

papamike

Well Known Member
Help!
I have stereo headset jacks and mic jacks from Spruce. I got 3-conductor shielded wire from Stein, per their recommendation.

My question is how to wire them. I've seen some video online where the shield is grounded. Stein documents say not to connect the ground. The Stein video is pretty straightforward, but again, there's no mention of doing anything with the shield. Grounding it makes more sense to me, but I don't want to redo this later.

I don't have anything else for the panel yet. Does this wiring depend on what will be in the panel, or is it standard?

Thanks
 
Standard procedure, to minimize ground loops, is to run left, right, and ground wires inside the shielded cable. Connect them to the jack. Insulate the jack from ground with fiber washers. Ground the shield at the audio panel only. Leave the shield at the jack end unconnected (trim it back to the insulation).
Same for the mike, where the wires are PTT, mike hi and mike lo (ground). If you’re sure you’ll never need a PTT switch at tbe mike jack, that wire can be deleted. Jack is insulated from ground with fiber washers, shield is connected to ground at the audio panel only.
 
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A good generic mic end pictorial here - courtesy of AeroElectric Bob -

http://www.aeroelectric.com/articles/micjack/micjack.html

As mentioned in the previous post some audio systems/panels use a 4 conductor cable with the shield grounded at one end only - usually the audio panel. Bob's example above uses 3 conductors and the shield as Mic Lo signal.

Soldering tips - no crimping here -

http://www.aeroelectric.com/articles/Jack_Tab_Soldering/Jack_Tab_Soldering.html

And a pictorial covering both mic and headset jacks from Stein -

Headset-Wiring-Graphic-1.jpg


Along with one showing how the jacks are usually insulated from a metal panel -

Fiber-Washer-Set-Diagram-600x600.jpg


Note that a mono headphone will only use the tip and the barrel connections.
 
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It's worth saying that it's acceptable (I prefer it) to use the shield as the ground return in audio situations like this. It saves one conductor (weight) and using the insulating washers prevents ground loops.
 
Ok. I think Bob Turner answered my question as far as the shielding goes. Thanks for the replies.
 
A good generic mic end pictorial here - courtesy of AeroElectric Bob -

http://www.aeroelectric.com/articles/micjack/micjack.html

As mentioned in the previous post some audio systems/panels use a 4 conductor cable with the shield grounded at one end only - usually the audio panel. Bob's example above uses 3 conductors and the shield as Mic Lo signal.

Soldering tips - no crimping here -

http://www.aeroelectric.com/articles/Jack_Tab_Soldering/Jack_Tab_Soldering.html

And a pictorial covering both mic and headset jacks from Stein -

Headset-Wiring-Graphic-1.jpg


Along with one showing how the jacks are usually insulated from a metal panel -

Fiber-Washer-Set-Diagram-600x600.jpg


Note that a mono headphone will only use the tip and the barrel connections.

Gil, reviving this thread as I am wiring my panel right now. If the jacks are already pre-wired including heat shrink, do I remove the heat shrink from the pilot Mic PTT tip and solder in the wire from the PTT switch, or can I splice?
 
Follow the install drawings for your radio and or intercom, they will indicate which side of the shield is terminated to ground. I just completed my install and it turned out great.
 
Gil, reviving this thread as I am wiring my panel right now. If the jacks are already pre-wired including heat shrink, do I remove the heat shrink from the pilot Mic PTT tip and solder in the wire from the PTT switch, or can I splice?

If your harness has the PTT line inside a shielded cable with the mike hi and low lines, I wouldn?t splice all of them. But if the PTT line is by itself, accessible, sure, cut it and use a crimp splice.
 
Gil, reviving this thread as I am wiring my panel right now. If the jacks are already pre-wired including heat shrink, do I remove the heat shrink from the pilot Mic PTT tip and solder in the wire from the PTT switch, or can I splice?

Some audio panel / intercom instructions will have a dedicated PTT pin in their connector in which case you can alternatively send one side of your PTT switch wire to that pin on the audio panel (or intercom) and the other side of the PTT switch to avionics ground. That's the case mentioned where you could use a two-conductor shielded wire for the mic jacks. It isn't a bad idea to use 3-conductor with the jack tip connected in case someone wanted to use a hand mic or portable PTT switch (unlikely). However, in your specific case you could just leave the pre-assemble jack as is and run separate PTT wires.

Here are a couple of diagrams I whipped up for you (stereo headphone jacks). I show the answer to your shielding questions in green and the PTT circuits in blue. The first shows the PTTs connected to the microphone jacks and the second (alternative) shows the PTTs wired direct to the ICS/audio panel.

DIAGRAM 1:

CgK8Vis.jpg




DIAGRAM 2 (ALternative):

0tSuRpt.jpg


The second alternative can be useful for PTTs installed on the sticks where it is more convenient to run their wires directly to the ICS/audio panel instead of looping back to the headset jacks. If the PTTs are installed on a panel near the headset jacks then the first diagram showing the jack connections might be more convenient.

Jim
 
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The tip of the .208" plug on my headset came off after I tried to straighten it. I've soldered up the tip, ring, and sleeve on the replacement plug to each of the three conductors indicated when I buzzed them out on the old plug.
There wasn't enough of the shield or drain wire left on the old plug to determine via continuity whether or not they should be connected to the sleeve. Should they be?
 
Usually use a pair of fiber washers to insulate the jack from the metal airframe, run the wires from the ring and sleve (tip only if you need the PTT line at the headphone) thru the cable. Connect the shield to ground only at the audio panel or transmitter.
 
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