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XLR and TRS connectors for small diameter wires
Old 13th October 2017
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Thread Starter
XLR and TRS connectors for small diameter wires

I'm about to remake all of my snakes and cables for my setup but am having trouble deciding what TRS and XLR connectors to use. The first time I made my cables I used all Neutrik, the ones with the strain relief. They work great for normal single channel wire, but snake cables have a much smaller wire diameter once they are broken out, and the Neutrik connectors do not hug the wire sufficiently, even if you trim the length of the strain connector piece (which is what it tells you to do for smaller diameter wires).

I was looking at switchcraft connectors this time. They have the two arms that I can clamp down to secure the wire, but wasn't sure if maybe there was a better solution out there. If you know of any quality connectors that securely fit smaller diameter snake wires, please let me know. Thanks.
Old 13th October 2017
Lives for gear
Richard Crowley's Avatar

Can you tell us where you saw instructions to trim the strain relief piece? If anything you may need to trim it for very LARGE wire diameter, but I would think that trimming it is the last thing you would want to do for small diameter cable.

Is you application in some sort of road-warrior setup where you are plugging and unplugging every night on the road or something? Else is actual "strain relief" all that critical for your situation (which admittedly we don't know as you haven't told us).

In cases where strain relief IS important for small-diameter wires I have used various methods of increasing the diameter of the outer sheath so that the connector strain relief piece would grab it better.
1) Use one or more layers of heat-shrink tubing. This also has the advantage of proving a "variable-stiffness" secondary strain relief if you extend the tubing beyond the end of the connector. For very small cables I have used several layers of "stepped-down" length so that the first layer is the longest, and then the next layer is a few mm shorter, etc. Another advantage is that you can use various colors to code the cables. Or even use clear heat-shrink cable to embed a small label identifying the wire, etc.

2) When I am terminating more "normal-size" mic cables, I save the ends of the outer sheath in a bag. Then I can use those pieces to slip over very small cables to "fatten them up" so that they can be grabbed by the connector strain relief.

3) Least elegant, but usable, you could simply use tape of some kind. Ordinary electrician's tape is OK, but most of the cheaper kinds from asia use adhesive which liquefies and runs after a few months/years. Better to us name-brand US tape like 3M, etc. Or the cloth-based stuff. I have sometimes used just a 1.5 inch / 35mm length wraped length-wise around the wire. Depending on the diameter of the wire it is sometimes just enough.

It is true that the traditional kinds of Switchcraft XLR connectors have a couple of grub-screws which bear down from opposite sides of the shell. But even those aren't sufficient for really small cable diameter. I always had to build up the diameter of smaller wire to ensure a decent grip.

If this is just for some semi-permanent installation in the back of a rack or something, robust strain-relief is not mandatory. Remember that there are roughly two different kinds of strain relief. There is "radial" stress on the connection where the cable goes off at some angle and the strain relief prevents bending at the connection point. IME, this is by far the more likely situation. The shell of any kind of XLR or TRS connector easily provides "radial strain relief" by moving the bending point well away from the soldered terminals.

The other kind of stress is "axial" where a cable is PULLED away from the connector. This should normally not be an issue because only an ignorant, ham-handed dufus would try to pull a connection out by the cable. Or if the cable was improperly dressed down so that someone would: (1) trip over the cable AND (2) the installer didn't leave enough of an excess loop so that someone tripping over the cable would attempt to pull it out.

IME, The AXIAL stress (pulling out with the cable) is where you need a good grip from the strain relief. And it is those situations (for cables for portable application on-location on the road where it is important to have good axial strain relief as well as radial strain relief.

I have started using Amphenol connectors from Redco and I think they are great (as well as being significantly lower priced than brand N or brand S, etc. The XLR shells have a sort of "labarynth" strain-relief grip which works for practically any diameter cable IME. Recommended.

The traditional kinds of TRS plugs use a metal piece which you crimp over the cable after soldering the connections. But this suffers from much the same problem where the scheme breaks down for very small cable. The same methods of increasing diameter apply here as enumerated above for XLR connectors. But there are other kinds of TRS plugs which use a shell identical to XLR connectors. They are too fat to plug into densely-packed sockets (like patch bays or the back of smaller mixers, etc.)

For really robust road-warrior appliations, I use an extra layer or two of heat-shrink tubing just for added radial protection as well as securing the sheath to the connector with half a dozen turns/knots of waxed "cable-lacing twine". It makes a VERY secure grip and is fast and easy after you practice a couple of times. Of course, for "fixed installation" kinds of scenarios, IMHO this is not necessary.

Some people put a heat-shrink tubing layer over the entire TRS plug shell, and extended up over the cable. This looks nice and provides some extra radial strain relief, but provides zero axial strain relief.
Old 13th October 2017
Lives for gear
Richard Crowley's Avatar

4) If you have the research time and access to samples, you can find some rubber/soft-plastic tubing which fits over the very small cable and provides a "normal-size" outer-diameter so that the connector strain-relief can grip it properly. Again, making this tubing a bit longer than the connector shell also provides some extra radial strain relief which may be important in some applications.
Old 13th October 2017
Lives for gear

Thread Starter
Thank you for the detailed response.

The Neitrik TRS connectors are the ones where you trim the strain relief piece for a tighter fit. By making it shorter, you allow the rear screw on cap to screw further, which in turn closes the mouth of the strain relief plastic piece even more, but even after trimming it doesn't grab.

I do not have a road dog set up - just me in my living room. I don't even do a lot of unplugging, I just didn't like having to create a workaround for proper strain relief such as adding bulk to the the wire so the connector will grab. I used electrical tape last time and it's one of those things that sits in the back of my head where I know the cable isn't 100% as cleanly assembled as I want it to be. I find it hard to believe there aren't TRS and XLR connectors designed to grab on smaller diameter jackets such as for snake cables, which are very common kind of cables.

I was trying to open the spec sheets for my snake cable to find the diameter of the wire but I'm having a hard time understanding the document.. it's like another language to me. And even if I could read it not all connector spec sheets show the minimum diameter it will securely clamp to. Seems like an inefficiency in this area of the market.

Anyway I bought a nice new solder station and some good solder and just need to make a decision on the connectors then I can order all the cable materials. Not sure why but inreslly enjoy soldering my own cables. Maybe bc I know I'm saving hundreds of dollars. Thanks again Richard.
Old 14th October 2017
Gear Maniac

FWIW the Neutrik PDF guide for their NP2/3 trs series states, "If using cable with OD > [GREATER THAN] 5.5 mm break away this part of the chuck." Unfortunately, snake cables are still a bit too thin for it to make a difference, though. Happy soldering!
Old 14th October 2017
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Thread Starter
Originally Posted by rmaier View Post
FWIW the Neutrik PDF guide for their NP2/3 trs series states, "If using cable with OD > [GREATER THAN] 5.5 mm break away this part of the chuck." Unfortunately, snake cables are still a bit too thin for it to make a difference, though. Happy soldering!
Yeah I had mentioned that already. I think I'm just gonna buy amphenol for the price and have to do a workaround.
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