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Old March 12th, 2012, 06:48 AM   #16
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Re: Wiring a 4-pin XLR for AC power?

I'm really confused. The device in the pictures is clearly a 12V lamp, with the usual 12V 4 pin XLR connector, plus and adaptor that has a car type 12V connector to fit into the 12 cigarette type output connector on the battery. There is NO picture I can see of the power supply - which no doubt connects to the battery pack with a dedicated connector. Have I completely missed something here? This kind of power supply arrangement is really common - and when the product is sold here in the UK, it is with a 230V ac unit rather than the US voltage unit. The battery is the same, the 12V connectors are the same, and so is the car type socket. This PSU change is the standard economic way to provide power to charge a 12V pack! The lamp you can buy as a replacement is also of course 12V.

Where is everyone seeing stuff that is getting them so excited? I see nothing at all that worries me here - just a 12V portable light running off a low voltage battery source.

While there was a mains version of the XLR connector, it was a very different type with red insulation and a very different application style. While popular with the BBC here in the UK, it didn't really take off on non-professional products.

This is the charger - which clearly uses the 12 automotive style socket as the means of charging the battery.

The only worrying information I can find is that there is a 120V AC lamp available, and this does seem to be powered via the XLR-4 connector. The connector, or at least the Neutrik version is capable of being used at 120V, although here in the UK, it's quite possible a person skilled in testing might decide that the connector is NOT suitable for our mains voltage and fail the item as also not having appropriate insulation.

Low voltage seems no problem, but I really do have issues with using what are almost known as standard 12V power connectors being used for much higher and destructive voltages. Maybe not against US law, but a damn stupid practice with very expensive side effects. I for one, seeing a dangling 4 pin XLR would assume I could plug it into the camera that has the same connector - a very expensive mistake.
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Old March 12th, 2012, 07:03 AM   #17
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Re: Wiring a 4-pin XLR for AC power?

I think you basically put a 120v bulb in and connect the 4 pin xlr to a mains outlet to 4 pin cable. Scary as the whole lot will be totally un-earthed!

We had those red mains XLR's at Tyne Tees TV for a while in the 80's but I thought they had been banned and one of our engineers managed to put a 3-pin audio xlr into the mains wall socket to prove the point! ;0)
Over 15 minutes in Broadcast Film and TV production: http://www.imdb.com/name/nm1044352/
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Old March 12th, 2012, 06:44 PM   #18
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Re: Wiring a 4-pin XLR for AC power?

hi paul

your last paragraph sums it up

from what i understood the manufacturer suggests using a cable with a mains
power plug on one end and the xlr on the other. this would involve running 120/240
volts through the plug. thats why i was excited (in a bad way)

it is very dangerous and it would not pass a test and tag test which makes it illegal in australia.

from experience i can say that mains power deserves all the respect you
can give it.
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Old March 12th, 2012, 07:28 PM   #19
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Re: Wiring a 4-pin XLR for AC power?

FWIW, I built the replacement cord over the weekend. This was my first experience with soldering an XLR plug, and Ian was entirely correct: "...there is not much room inside, and no insulation... "
Before building it, I again closely examined the one cord that I didn't lose. This is exactly as it arrived with the lighting package when it was new, so I had something working on which to base my steps.

My examination revealed that each soldered connection was protected/insulated with black heat-shrink tubing. So, with careful insulation - and everyone's warning - in mind, I duplicated that set-up. Before soldering, I slipped on some very carefully-measured heat-shrink tube for each pin-to-wire connection.

I ended up using 16 AWG multi-stranded wire rather than 18 AWG, and had to use a typical/common 2-prong plug (the type where each wire is screwed to its' respective prong) for the mains end, because I couldn't locate a 10 foot cord with a molded-on plug.

I then went about soldering one wire to pin 1. Working with the short "barrel" for pin 1 took longer than I hoped, but I was going slowly, being careful not to damage the XLR innards. (I even stuck a probe into the receiving end of the pin 1 barrel to serve as a heat-sink and hopefully prevent damage to the XLR. Once soldered, I allowed it to cool for a couple of minutes, then slid the heat-shrink tub over the connection and used a heat-gun to shrink it to fit. That worked well.

Moving onto pin 4, which had a longer :barrel", I repeated the procedure, e.g. soldering, letting cool a bit, then slipping the heat-shrink tubing over the soldered connection and heating it to shrink. This too, worked well, and, in fact, went a bit faster and smoother than pin 1.

Next I slid some heat-shrink tubing over the cord to help fill the gap at the hole where the cord enters the plug. (Unfortunately, there was not enough room inside the plug to provide any strain-relief, and unplugging it would simply have put unnecessary presssure/strain on the soldered connections). I did this in 4 layers of heat-shrink, i.e. put 1 layer in place, then heated & shrunk that, then repeated that process 3 more times, with each layer of heat-shrink slightly shorter than the previous one.

I connected the wires to their respective prongs, made sure I had a 120V bulb in the lamp, donned my heavy rubber gloves, plugged the cord into the wall outlet, then turned on the lamp. It worked fine...no sparks, no blackouts, no tripped circuit breakers, no glow over Manhattan.

Here's a link describing the lights I own:
Smith-Victor SV840K AC/DC Video Light Kit and Charger 401141 B&H
Unfortunately, the photo doesn't show the AC-to-4-pin XLRF cord. However, if you check out the link, then click on the "What's in the box" link, you'll see mention of an AC to XLR adapter. It is that piece that I've assembled.

This light has been on the market for some time, and has received mostly good reviews at the B&H site. I'm confident I've at least replicated the cord that I used as my guide and, unless the manufacturer has been shipping unsafe fixtures for a few years now, expect to be able to return to using this lamp again both on and off camera.

Thanks again for everyone's concern, advice, and warnings. I'm not much of a gambler (particularly with my personal safety and my equipment), and appreciate all the advice.

Just so you all don't think I'm absolutely crazy, here's a link to the manufacturer's web site describing the fixture. Note mention of using AC power with a 10ft AC-to-XLR adapter.
Our actions are based on our own experience and knowledge. Thus, no one is ever totally right, nor totally wrong. We simply act from what we "know" to be true, based on that experience and knowledge. Beyond that, we pose questions to others.

Last edited by Denis Danatzko; March 12th, 2012 at 07:43 PM. Reason: Addendum
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Old March 19th, 2012, 07:26 PM   #20
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Re: Wiring a 4-pin XLR for AC power?

XLR's are pretty roomy inside... try a TA5 sometime.

anyway, I did have a AC Edison ->XLR4 for doing exactly the same thing- powering 120V bulb in a ProLight. I had not used a 12V bulb in that light in years, but still wanted the easy power option to do so. I eventually sold that light. while I had it, I never had the power cable off of the light.

you can tag / label the wire end if you want to make it more obvious... that said, the WORST connector I'd seen used for power was a XLR 3. why ? because they are cheap. however it WAY WAY WAY too easy to send power into a mic input and fry it... and if thats all you do you where lucky.

the big danger is mainly putting 120V into something that wants 12ish V and releasing the Blue Genie :(
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