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Alexa Mini TC sync

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In order to find out which lead goes to which pin, I had to open up the LEMO connector. Closer inspection of the connector shows that the wiring diagram in the Arri Alexa Mini User Manual is actually not accurate. Unlike the standard LEMO 0B Timecode connector, which has the ground pin on top, the LEMO 00 Audio connector has the ground pin above on the left side seen from the soldering side and the pins are probably numbered counter-clockwise from 1 to 5 as on the LEMO 0B TC connector.

In the Arri-made cable with flying leads, the white wires seem to be signal high and the blue wires signal low. You'll have to test continuity from the pins to the wires to know which one's which.

I'll test my cable tomorrow on the set, I hope it'll work, otherwise I'm screwed.

Here's a little diagram showing the actual pinout.

Alexa Mini Audio Input LEMO EEG.00.305.jpg

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On 16/04/2016 at 5:21 PM, chrismedr said:

i'm a bit confused by the two diagrams - why is the "guide notch" once next to a pin (1) and once between two pins (1 and 5)?

it looks to me like the wouldn't fit together at all but i'm probably reading things wrong.

Hey Chris,

The diagram on top is the one you'll find in Arri's Alexa Mini manual, and it's wrong.

The diagram below is the actual orientation of the pins in the LEMO 00 plug, with the guide notch between pins 1 and 5.

Astro's diagram is correct, that's the absolute correct way to wire the plug. Thanks Astro!

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  • 1 month later...
  • 2 weeks later...

I just finished a 37 days shoot with Alexa Mini, a Tentacle Sync box on both cameras and a Tentacle box on my recorder as well, the output volume of the Tentacles cranked all the way up. 24 fps. The Minis' TC options set to EXT LTC - REGEN - FREE RUN (there's no PRESET option in the Alexa Mini). Sync stayed within half a frame all day long every day without rejamming the Tentacles on lunch break for the whole shoot. The AC told me we had the latest firmware on the Alexas.

BTW, all audio channels were disabled on the cameras, as we recorded a scratch track on a Video Devices PIX and an Odyssey 7. My Mini Lemo 5-pin Audio cable worked great until we decided to disable the onboard audio as we didn't have any use for it.

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  • 2 months later...

Good evening,

Anyone used the alexa mini with lockit ACL 204 to tc with Sound Devices 744T?

I have a shooting tomorrow and haven't used the lockit before, what tc settings should I use on my sound devices /lockit/alexa for an easy and hustle free setup.

Also, should I leave lockit conected to the alexa after jaming my sound devices?

Any help would be much appreciated as I'm starting to sweat here....:)



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The manuals are all readily downloadable on the manufacturers' sites. I'd expect at least the Lockit manual to explain precisely your setup (sound recorder, camera, lockit box) as this is the very basic standard scenario. Probably it's in the 744 manual somewhere too.

In short: 744 is master on 24h run. Sync ACL from 744, set cam to external TC, leave ACL connected to cam all the time.

Edit: you need to know what standard framerate they're shooting at, of course.

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Free Run: you set the TC independently from system time. You will need to do so when the machine has been switched off and disconnected from power for a certain time, but normally it will hold fine during battery changes during the day.

24 hr run: recorder on startup jams TC to its system time. As it does this on a reboot too, and system time isn't as accurate as the Ambient TC chip, you might get offsets when you don't re-jam the other devices. I prefer 24hr because it saves me setting a TC value, and I leave the 788 on external power and internal backup battery all day.

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  • 3 weeks later...
11 hours ago, paul55 said:

I have some right angle Lemos for mini coming but only 10

If you go for a RA Lemo, just be aware that there may be several options available for what direction the Lemo goes. They are not like the  XLR RAs , which can be directed to . The problem with the RA Lemo I bought is that it angles down, and the camera guys complain that it must be removed each time they change a memory card. Some may argue that this is good practice (re-establishing the sync) but that is not what the camera dept wants to hear, or deal with.

Have gone back to regular Lemos. They don't really want to jam up anything too close so they can access to the memory cards, anyway.

Just my 2 cents. (cents now extinct where I live, so we'll have to come up with a new expression here;)




Jim Rillie

Production Sound Mixer

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