XLR Plug Issue

[HO RacePro]

At an IHSR race event in September I had an issue with the XLR plug on my controller. While it appeared to be fully plugged into the jack at my driver's station I had only intermittent contact. I was able to continue racing because I had made an XLR plug to alligator clips adapter. I used the alligator clips to bypass the problem.

In an attempt to discover what had caused the issue I purchased a new XLR plug from Slot Car Corner. That plug turned out to be the same brand as the one I had installed -- Neutrix. But when I compared the two plugs I discovered a difference. The small metal clip that's used to hold the XLR connectors mated was damaged.



In the photos above the plug on the left shows the damaged clip. It is not fully inserted into the plug and is bent. The plug on the right shows the clip properly inserted. I believe the damage to the clip prevented my XLR plug from making proper contact with the jack at the driver's station. The photo below shows better how that clip should be installed.


I think how the clip came to be pushed forward and bent was improper installation of the strain relief. There are bosses on both the plug and the strain relief that need to line up for insertion into the metal shell of the connector. Correct alignment of those two bosses is shown below.



If those bosses are not correctly aligned the strain relief can push the clip forward, out of position, where it can be bent by the force of connecting the plug to the jack. That, I suspect, is what caused the poor contact I experienced at the track. The photo below shows how the strain relief should clear the clip when everything is properly aligned.



I won't really know if fixing the clip will fix the intermittent contact until I get to use that plug on the track again. But there's no question that the bent and out-of-position clip was not right, and I'm pretty sure improper assembly was the cause.

XLR connectors are becoming popular for slotcar controllers. I really do like how fast they hook up and the way they are held together. I'm hoping not too many people experience the kind of issue I had. But here is a heads-up for anybody installing them.

Ed Bianchi

[RichD]

I have been using XLR connectors for many years. I used them on my microphone cables long before they were used for slot racing. The pins on the male connectors are very long, so they should make good contact, even it the male connector does not want to lock in place with the female panel connector. The connector that you show does not look like any male XLR connector that I have, including ones that I got from SCC years ago. With the connectors that I have the clip is not visible once the connector is fully assembled. It includes a strain relief that I crimp on to the wires after I have soldered them to the pins. A small screw goes through the outer housing and threads into the clip. The clip should not make an electrical connection with any of the wires, all it does is to keep the pins from pulling out of the housing when you unplug the connector.
I suspect that there is a problem with the female panel connector, did you try plugging into another driver's station? If the problem was with the male connector using an XLR to alligator clip adapter would not have solved your problem.
The connector that you show has a plastic insulator to keep the wires from grounding out on the housing, I presume that it squeezes up on the wires when it is inserted into the housing to also act as a strain relief. With the connectors that I have used a little electrical tape is needed to avoid any shorts.

[HO RacePro]

Well shoot, I made a mistake...

That little clip I've been going on about has nothing to do with the mechanism that holds an XLR plug and jack together. Those features exist in the connector shells. What that clip does, apparently, is give you a way to make electrical contact between the shells and the shield of a shielded cable. You can solder said shield to said clip. And the clip has a spring feature to contact the shell.

Since our controller cables are not shielded that clip is superfluous. You can remove it entirely and thus avoid any issues it might cause by being out-of-place.

Or you can bend it, as I've shown below, so it will stay put.



I've still got to try it out on the track where I experienced the intermittent contact. That might not happen for a while.

I'd be very interested to learn the brand of XLR connctors RichD has been using. Both my plug and the track's jacks are Neutrix connectors. They are sold by Slot Car Corner. I thought I understood that XLR connectors were originated by Neutrix, which is why I bought that brand in the first place. I wanted to make sure my connectors met the standard.

But perhaps that's not the case at all. I used to design electrical connectors, and I am well aware that many companies produce their own variations of standard designs. Sometimes carefully tweaked to avoid patent infringement. And it is not unknown for said tweaks to cause issues.

There should be no reason why my Neutrix XLR plug won't work perfectly with that track's Neutrix XLR jacks. Maybe there is more to learn here. I'll report back when and if I learn more.

Ed Bianchi

[Pappy]

I learned a lesson on XLR's. I bought some cheap one's on Ebay for my controllers that I let people use that weren't Neutrix and they wouldn't fit in the Neutrix connectors on my track. Stick with Neutrix and you won't be sorry.

[HO RacePro]

Well, at least for now I will stick with Neutrix, but I am truly disappointed to have confirmed that mixing brands does not always work. Love the XLR features. Hate their issues. Wish we had settled on a better option.

Ed Bianchi

[dinglebery]

Neutrik is the industry standard XLR manufacturer - pro audio, custom A/V, and high end audio products worth their salt all use Neutrik connectors for balanced audio. They're also the industry standard for the Speakon connector.

[HO RacePro]

Oh I am ashamed...

I have been misspelling the brand of my XLR connectors. They are Neutrik, with a 'K' -- not Neutrix, with an 'X'. Plainly labeled on the connector shells. So assuming dinglebery got his spelling right my connectors are the "industry standard" he cites.

It turns out that there IS a brand of XLR connectors labeled Neutrix, with an 'X'. At least they are listed on eBay spelled that way. Not the genuine Lydia Pinkham's. Oh the deceitfulness of our world!

I almost wish my connectors were the off-brand. Then I could replace them with the Real McCoy and hopefully be shut of all performance issues forever. Not so...

So, Pappy, are your connectors with a 'K' or an 'X'? Please check.

Ed Bianchi

[Pappy]

They are the K. I wasn't sure of the spelling so I just copied yours. LOL
Proof that two wrongs don't make a right. LOL

[HO RacePro]

On the other hand, three lefts make a right.

[RichD]

When I started doing live recordings back in the mid '70s XLR connectors were often referred to as Cannon connectors. With the Cannon connectors the insulating material that held the pins in place was rubber. I used condenser mikes that required XLR plugs and I bought the wire and plugs separately to make up my own cables. The brand of plugs that I used was Amphenol and those used a green hard plastic as the insulating material. I just looked at the plugs on my controllers and those are marked NT with the T overlapping the N, I presume that is the Neutrik logo. I am not surprised that there may be an inferior knockoff brand lurking out there. For my HO track I bought some generic XLR female panel mount connectors that proved to be unsatisfactory and I replaced them with Neutrik connectors from Slot Car Corner.

[dinglebery]

Amphenol makes a great connector as well. Was it Mogami cable you purchased to make your mike cables... I wonder.