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Nomad users: What are the specs on your Breakaway Cable?


Adam Aslan

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For anyone who is really interested in this, don't take my word for it. Simply take a 200 ohm resistor, solder it to an XLR on one end, plug the other end into a mic input, put on your headphones, and flex the cable. The connectors used to terminate it have absolutely nothing to do with the issue, it is solely a function of the shield design.

For what it's worth (not much, these days), I have built probably 350,000 feet worth of multi-pair snake systems over years, for remote trucks, stage venues, and studios. I've used just about every brand of cable made. They all have their pros and cons. Probably the best cable I ever had the occasion to use was the older style EMT cable (not the same as the current design), which is unfortunately long since out of production. (If you are ever fortunate enough to find some, buy it immediately!) I also like the Klotz and Sommer cables, but the configurations are somewhat limited.

Canare has made a solid design for years (the L4E3 series, which has a tightly braided shield, is used by a number of cable fabricators here and in Europe for umbilicals). I have, however, occasionally had a bad run here and there over the years, where the cable core and filler were not wound together properly, causing the pairs to become mis-formed under the outer jacket. This hasn't happened in quite a while though. We have used Canare cable in every kind of environment imaginable, and short of being cut by equipment, they have never failed. Like most other cables, though, they do tend to wick moisture (even through the jacket), which will eventually corrode the shield. Nothing lasts forever....

Again, you don't need to be a rocket scientist do these tests. If you know how to use a soldering iron and have 15 minutes of time, you can hear it for yourself. (It is actually a pretty instructive exercise for understanding cable design). I would also recommend doing tests with different cables exposed to an RF field. A 5 watt UHF walkie serves as a great source. While it doesn't provide a calibrated source like an RF chamber, it gives you a pretty good idea of how a given cable reacts to an RF field (use a mic pre with good front end RF filtering for the tests, so you don't confuse the effects of RF on the mic pre with the effect on the cable),

--Scott

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  • 2 months later...

After a couple of delays(Remote Audio CA3PS26 being out of stock, and my Purchasing Dept. at work misplacing the PO... 3 months!) and the parts sitting around, I got 200' of the CA3PS26 cable from Trew Audio Nashville.

Totally psyched... started to lay out the situation when I ran into a roadblock:

The diameter of the cable(approx. 8mm) is larger than the for the Neutricon SR8 strain relief cap... damn! Figured that this is the cable and connectors that Remote Audio uses for their breakaways, what's known as a "no-brainer". Hmmm.

So what to do...

First thought was to drill out the SR8 screw-on cap. May have worked but after waiting this long to assemble the parts, I decided to look at an alternative method.

Went back to the Neutrik docs and looked at the alternate strain reliefs, the SR8A and SR8B. These are designed to crimp onto a cable rather than use the plastic toothed strain relief insert that the SR8 uses. The diameter ranges from 3-8mm. Decided to get the SR8B's, ordered up a batch from Mouser.

Got the SR8B's and unfortunately they would still not be able to crimp the cable, but with a bit of work I was able to fashion a combination of the SR8B cap and the SR8 strain relief for a working solution.

Started by pulling off the SR8B rubber boot from the cap. This cap has a larger diameter hole than on the SR8 cap which the cable would easily fit through. There is another plastic piece inside the cap which I would describe as a large shoulder washer. The cable fits through the "washer" but is quite snug, so I removed it. I did not use the metal crimp or plastic insert parts from the SR8B kit.

I then did a test fitting using the toothed strain relief from the SR8 and the modified cap from the SR8B. Though a tight fit, the cap can be screwed down onto the SC/MC8 connector shell.

Another problem arose however… there is some play between where the strain relief seats in the connector shell and the cap, allowing it to be pulled back even though it is eventually stopped by the cap. So I reinserted the "washer" into the cap and it holds the strain relief properly. A bit of work with a circular file enlarged the washer to a comfortably tight fit and an added bonus, the shoulder on the washer will give a nice finished appearance to the assembled cable end. The strain relief is very snug, should stand up to years of service.

So with that hurdle cleared it's time to start making cables!

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Wandering Ear told me that the 3 channel Remote Audio cable on his breakaway snake has the filler rope removed at the ends where it enters the bushing (cap). He doesn't know how they removed it up and into the cable itself. Personally, I just drill out the bushing and then it fits Mogami 2931 with ease. The drill bit is 23/64 but a 11/32 ought to work.

With the stock chuck and bushing there is no play and I have used mine for many years without fail.

Mark O.

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I have a similar setup to Jack for my Nomad and 302 breakway cables but using 7 pin neutriks. On the Nomad side I have opted for the 2 XLR outputs rather than the ta5 output just incase I want to use it for something else in the future. Whatever that may be.

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I built all my breakaway cables with two sets of Neutricon 8 pin connectors. So that I can have several mixer ends as well as several camera ends and I just run the appropriate length of cable between them. I have several 15 and 25 foot runs of cable - so I can use just one length or add an additional length to the run if necessary.

As for the mixer end I built two cables that each have two TA5's on them - one TA5 is the two channel camera send and the other is the two channel (stereo) camera return. I also have a similar mixer end that has two XLR females on it.

The attached images are two photos of the mixer end - withTA5's and one of the camera end.

Jack, I like the mini-bungee idea.

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The construction continues.

I cut off the two finished Neutricon ends and started a Nomad end(2X TA5F -> OSC8M) and a camera end for a Panasonic AJ-SDC615 DVCPRO camera(2x XLR-3M/XLR-5F -> MC8F)

I used a piece of Coleflex to encase the L/R and had to drill out the TA5 cap with a #2 drill in order to fit the two pairs along with it. Taped it back with a piece of gaffer's to keep it out of the way while prepping/soldering. Crimped the shell to only one of the pairs and then trimmed the Coleflex to fit within the cap.

The camera end was cake compared to the Nomad end...

Finished products at the bottom. Will add a strain relief of some sort down the road to both.

post-4514-0-10954600-1354815927_thumb.jp

post-4514-0-01933400-1354816157_thumb.jp

post-4514-0-17889200-1354820570_thumb.jp

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Yep, those are the ones I had.

I went on to make another Nomad end and camera end, and 2 each 15' and 25' extensions. All told 12 Neutricons over three days or so... my hands were quite stiff afterward! :-

Also I experimented with drilling the original bushing for the Neutricon... a Q drill(.332" dia.) is the perfect size for CA3PS26 and leaves plenty of material.

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  • 2 months later...

I bought a length of Remote Audio's 3-pair breakaway bulk cable from Coffee Sound and it works like a charm.  It is spiral shielded not braided but exhibits none of the handling noise that my 2931 made.  I think I got a bad batch of 2931 from Markertek because I used the same techniques on the Neutricon and the breakout ends and here it made no noise.  

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  • 8 months later...

when i make them up, i use pin 6 - from the SD wiring that has pins 6 and 8 unassigned.

what i have found though, is that you have to use multipair for your umbilical, and make sure that your return is wired as its own pair to minimise timecode bleed on the return. 

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Anyone here not using any pins for ground?

 

I'm looking at building an umbilical and a few sets of tails based on 7 pin XLR.

So I'm wondering if I could have:

4 pins for 2 balanced audio sends.

2 pins for stereo return.

1 pin for TC.

 

Thoughts?

if you want to use the 7 pin XLR like that, consider using the shell of the XLR to make your ground connection for you fanouts.

 

as the senator alluded to, you are asking for trouble if you dont have a ground connection.

 

and there is nothing better than trying things for yourself. i have learned a lot of ways not to do things like that.

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Anyone here not using any pins for ground?

 

I'm looking at building an umbilical and a few sets of tails based on 7 pin XLR.

So I'm wondering if I could have:

4 pins for 2 balanced audio sends.

2 pins for stereo return.

1 pin for TC.

 

Thoughts?

You will not be able to complete the circuits w/o a ground connection. Using the ground tab in the XLR will not do it as that is a chassis ground not a circuit ground. 

 

Eric

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