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LEMO connectors


MatthewFreedAudio

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Anyone here assemble their own Lemo connectors for Zaxcom wireless, or any other Lemo connectors? What all is needed for tools?

For Zaxcom transmitters, I've wired 3-pin Lemos of both the screw-on type and the push-pull type. I've also wired a few 5-pin Lemos for time code.

Mainly, you need a soldering iron that allows you to solder tiny wires to tiny pins that are really close together, a way to hold the connector (pliers and a rubberband works), tools to strip the wires, good glasses, steady hands, and plenty of patience.

If you've worked on tiny stuff before, you'll be fine if you make sure you're not in a hurry. One of the keys with wiring a mic for a Zaxcom transmitter is to make sure you connect the cable shield to the shell.

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The 4-pin Lemo that plugs into my stereoline has 2 half-barrels that fall out when you slip the sleeve off. Getting the half-barrels to stay in place while slipping the sleeve back on - after fairly straight forward soldering - makes it the toughest, most frustrating connector I've worked on.

Yes. I just made 2 RED TC cables with the same connector and it was tough.

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One of the keys with wiring a mic for a Zaxcom transmitter is to make sure you connect the cable shield to the shell.

Hi John,

could you explain the best way to connect the cable shield to the shell?Do you have to solder or you simply lock the cable shield in the shell?

Thanks!

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Hi John,

could you explain the best way to connect the cable shield to the shell?Do you have to solder or you simply lock the cable shield in the shell?

Thanks!

I use the metal strain relief collar and trap strands of the shield under it. When it's tightened down, they'll make good contact from the pressure. You must take your time and carefully trim and fan the strands so you don't have a thickness that the collar won't fit against. Try a few single strands (not crossing each other, which would add to the thickness), and you should be fine.

With the screw-on type connector, you'll need the proper tool to tighten the collet down onto the collar. The pliers you need is a small pair with two tiny round tips such as used for a spring keeper of the type that has two holes that allow you to expand the spring. Instead of that, you can get by with what I call "nibblers" which are the little thin side cutters for trimming wires flush with a circuit board, etc. The tips of a small pair of those can work to fit into the notches of the collet to tighten it against the strain relief collar.

Good luck, and remember, lots of patience and you'll be okay.

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I use the metal strain relief collar and trap strands of the shield under it. When it's tightened down, they'll make good contact from the pressure. You must take your time and carefully trim and fan the strands so you don't have a thickness that the collar won't fit against. Try a few single strands (not crossing each other, which would add to the thickness), and you should be fine.

With the screw-on type connector, you'll need the proper tool to tighten the collet down onto the collar. The pliers you need is a small pair with two tiny round tips such as used for a spring keeper of the type that has two holes that allow you to expand the spring. Instead of that, you can get by with what I call "nibblers" which are the little thin side cutters for trimming wires flush with a circuit board, etc. The tips of a small pair of those can work to fit into the notches of the collet to tighten it against the strain relief collar.

Good luck, and remember, lots of patience and you'll be okay.

Thank you John for your exhaustive explanation.

Really helpful!

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I was just reading another thread on LEMO connectors and bumped into this thread. From my experience, it is important to "ground" the cable shielding to the metal connector shell for shielding purposes, i.e. to shield the signals from external electrical noise. You can invert the shield (turn it inside out) and clamp down on the cable collet.

Also thought I share a vendor I use for equivalent LEMO connectors for those who might be cost-conscious:

Male Plug:

http://www.keywolf.com/metal_male_solder_plug.php

Connector Configurator:

http://www.keywolf.com/pn_config.php

Have a great one.....

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  • 4 weeks later...

I've spent over 30 years making up my own cables but have never come across anything as small as these. Give me a TA5 any day. Trying to wire up my Cos 11 to the novel Lemo is like doing open heart surgery on an ant.

I'm sure patience will get me there, I just hope I'm left with some cable on my mic

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People that can't solder an XLR properly should not consider something small like the LEMO!

One area that is important is that the cable clamp collet must be sized appropriately for the cable diameter. There are options here and you need to measure the cable diameter and specify the exact proper collet. Too small and you will never assemble the connector. Too big and you won't have any strain relief on the cable. Heat shink might fill it but it is best to do it properly.

The nuts require metric wrenches of the right size. "Ignition wrenches" are best. Pliers should never be used on nuts. (Learned that lesson young from my aerospace engineer father!)

Very carefully strip and tin the conductors. The length is specified in the catalog for that particular connector. Too short and it is imossible to assemble. Too long and the collet strain relief doesn't work.

The key to soldering them is to have a good iron like the Weller TCP series. You need enough heat to get the joint fast but not too much heat.

Although I've been doing them for years these days I turn most of this kind of work over to a friend, Kris Handwerke, because she does a much better job!

Bill Ruck

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One area that is important is that the cable clamp collet must be sized appropriately for the cable diameter. There are options here and you need to measure the cable diameter and specify the exact proper collet. Too small and you will never assemble the connector. Too big and you won't have any strain relief on the cable. Heat shink might fill it but it is best to do it properly.

Never soldered a lemo - but how do you size and "crimp" the collet. Do you need a special tool?

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Jack, the 5 pin Lemo that we use for timecode actually comes in a few different 'cable diameters'. This just means, the bit inside the conector that bites down on the cable for strain relief needs to matched to the diameter of the cable you intend to install in the connector. If the cable is too big for the collet, it won't go together. Too small, and there will be no effective strain relief as the cable is smaller than the smallest diameter the collet can tighten down to.

Hope that makes sense.

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  • 1 year later...

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