music jack wiring

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hydroguy2
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music jack wiring

Post by hydroguy2 »

Mr Thumbs here.

I have a tiny 1/8" music jack which I need to wire and install. Problem is it has 5 lugs to solder to and I only have 1 wire going to the intercom. Anyone have a sketch on how I'm supposed to hook this up.

now where's my hammer? :bang:
Brian
Townsend, MT

jwyatt
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Post by jwyatt »

Is it possible you ended up with a normalling jack? These would have the 5 solder lugs you're seeing; the two extra lugs are connected to the tip and ring terminals when there is no plug inserted, but disconnect when the plug is inserted.

See diagram D:
Image
...the two points with the arrows are the normalling points, and the connection at the tip of the arrow is broken when a plug is inserted. We commonly use these in the audio world for patch points or test points, allowing the "normal" signal in a path to be overridden.

If this is indeed what you've got, it can still be used as a regular jack--just don't connect the normalling lugs. You probably want to ring it out with a meter to be sure of what's connected where, then connect your three wires to the three appropriate lugs (for stereo music: shield/ground->sleeve, left->tip, right->ring for stereo music), leaving the other two (the ones with arrows in the diagram) with no connection.

Hope this helps? :?
Joshua Wyatt | Vasa, Minn.
RV-9A N627DW @ KRGK
Flying: Phase I complete
rv9a.pacificrimsound.com

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hydroguy2
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Post by hydroguy2 »

yep, that helped. Apparently, I have a normalizing plug. and I have figured out which lugs NOT to use, and which one goes to ground. BUT....my intercom only has 1 input, so should which lug goes to the intercom input or do both?
Brian
Townsend, MT

jwyatt
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Post by jwyatt »

If your intercom is mono, you have a few options:
1. Take just one channel of the music input (usually the left channel--the tip lug--is taken, which has the side benefit of allowing it to still work should you ever plug music into the jack with a mono plug). Leave the ring lug un-connected. Simple and easy, and probably sufficient for basic in-flight music, though you may notice something "missing" from stereo program material...

2b. Combine the left & right into mono--the audio guy way...wire the jack with a summing network to create a mono signal from your stereo input.
Image
...ignore the output jack on the right side -- those two wires would go to your intercom, rather than to an output jack. 1/4 watt resistors are fine, and you'll never notice the difference in this application if you use 5% instead of 1% tolerance. There will be a loss of level with this method, depending on your intercom that may or may not be a problem.

2b. Combine the left & right into mono--the PS Engineering way...wire the sleeve lug (ground) to your intercom's music input ground, then wire both the tip & ring lugs to your intercom input's signal line. Easiest to jumper the two lugs at the jack and run one wire back to the intercom connector. No level loss on this method, but your audio device may not be completely happy with it.

Probably more than you needed...what's the old saying, "never ask an engineer for the time, he'll tell you how to build a watch"? (Not a real engineer, but I fit some of the molds :oops: )
Joshua Wyatt | Vasa, Minn.
RV-9A N627DW @ KRGK
Flying: Phase I complete
rv9a.pacificrimsound.com

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hydroguy2
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Post by hydroguy2 »

Thanks Josh. Should be able to get it working now.

I have enough info to be dangerous.
Brian
Townsend, MT

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hydroguy2
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Post by hydroguy2 »

Well, turns out I'm a moron!.....not really new news.

I took the info Joshua gave me, then went to the shop to figure things out. Next looked at my intercom wiring, located the music input wire #18 AND a music input spare #19...what I don't recall labeling a spare. So I broke out the intercom paperwork, low and behold....tada, my Stereo intercom needs 2 wires! So #19 goes to left channel which is the tip lug and #18 goes to sleeve lug for the right channel.

Got it all wired up, now all I need is one of the new-fangled Ipod thingamabobs.

Good news for the day: I tested my Comm when I heard a plane overhead. The guy in the pattern reported "loud and clear", while the guy on the ground said it was a little scratchy. Good enough for now, since he was several miles away and I'm inside a steel building.
Brian
Townsend, MT

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