# Comms Blazer



## Eboy87 (Mar 13, 2008)

I'm looking for one of these, anyone know where to find one that doesn't cost an arm, a leg, and a first born child? DIY is perfectly acceptable too. System is Clear-Com, people are getting pissed that I'm not on comms while mixing, and can't see the call light.

Yahoo just gave me a whole bunch of Chevy and telecom hits.


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## soundlight (Mar 13, 2008)

I'll assume $150 is an arm and a leg (but not the kid) and post anyways:

Production Intercom Blaon/4 is the cheapest one that I've found. All of the pro audio companies that I have actually done shows with use the Blazon/4 units (with gaff tape around half of it so that only the engineer can see the flash) and handsets.


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## avkid (Mar 13, 2008)

CBC Technical production outlet:
http://productionoutlet.com/product_info.php?products_id=3453


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## Andy_Leviss (Mar 13, 2008)

Check out the Com-Bit. It's an LED call light built into a right-angle XLR connector. Easy to mount wherever you need it, I tape it to my meter bridge. $25, and Paul offers, school and union discounts. Tell him I sent ya!
Here's mine on my last steady mixing gig, you can just barely make it out (since it's not lit) above the rings in the script binder on my script tray:

http://ducksecho.com/misc/celia_combit.jpg

--A


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## Eboy87 (Mar 13, 2008)

Thanks for that link Andy, I may have to pick one up. Looks like it gets its own XLR com run, not a pass-through, correct? Either way it's perfect since I mainly need it for theatrical work.


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## Eboy87 (Mar 14, 2008)

With our beltpacks? Yes, since we have a loop through.


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## Andy_Leviss (Mar 15, 2008)

Eboy87 said:


> Thanks for that link Andy, I may have to pick one up. Looks like it gets its own XLR com run, not a pass-through, correct? Either way it's perfect since I mainly need it for theatrical work.




As others noted, you can chain it off the beltpack or, if you prefer, just pop a Y-cable on it for a pass-through, since that's all the beltpack pass-through is doing anyway. 

--A


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## avkid (Mar 16, 2008)

I saw a cool ad in my new issue of Live sound International for one of these little devices:
http://www.asl-inter.com/read-more.aspx?id=1245


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## Footer (Mar 16, 2008)

avkid said:


> I saw a cool ad in my new issue of Live sound International for one of these little devices:
> http://www.asl-inter.com/read-more.aspx?id=1245



I know they have coms built into consoles, has anyone built a large call light into one?


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## porkchop (Mar 16, 2008)

avkid said:


> I saw a cool ad in my new issue of Live sound International for one of these little devices:
> http://www.asl-inter.com/read-more.aspx?id=1245



There neat, but not $90 neat. I'm sure there's info on the pinout of the cable in the intercom system. I bet a little research, a spare connector, a $.05 resistor, a $5 LED, and a few solders would go a long way.


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## Footer (Mar 16, 2008)

porkchop said:


> There neat, but not $90 neat. I'm sure there's info on the pinout of the cable in the intercom system. I bet a little research, a spare connector, a $.05 resistor, a $5 LED, and a few solders would go a long way.



Thats my thought as well, there really can't be all that much to it.


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## avkid (Mar 16, 2008)

Footer4321 said:


> I know they have coms built into consoles, has anyone built a large call light into one?


I might just know a guy that can do something about that.
I'll get back to you on that in a few months.


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## Andy_Leviss (Mar 16, 2008)

porkchop said:


> There neat, but not $90 neat. I'm sure there's info on the pinout of the cable in the intercom system. I bet a little research, a spare connector, a $.05 resistor, a $5 LED, and a few solders would go a long way.



Indeed. Call signal is just 30V DC superimposed on the audio line (pin 3), so I'll save you that part of the research 

(This is why a pin 2-3 short causes intermittent phantom call signals, since it's shorting the 24-30 VDC supply from pin 2 onto the audio line, which looks just like a call signal to the stations on the line.)

But if you are going to go prebuilt, I still like the Com-bit better, I think the right-angle connector's a bit easier to mount, and at less than 1/3 the price, well, the math is pretty easy.

--Andy


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## porkchop (Mar 17, 2008)

Andy_Leviss said:


> Indeed. Call signal is just 30V DC superimposed on the audio line (pin 3), so I'll save you that part of the research
> (This is why a pin 2-3 short causes intermittent phantom call signals, since it's shorting the 24-30 VDC supply from pin 2 onto the audio line, which looks just like a call signal to the stations on the line.)
> But if you are going to go prebuilt, I still like the Com-bit better, I think the right-angle connector's a bit easier to mount, and at less than 1/3 the price, well, the math is pretty easy.
> --Andy



So basicly go from pin three through an appropriate resistor (found easily at http://www.ledcalc.com to an LED of your choosing. Then to tie it all together, I assume pin 1 for a ground???? If so the most expensive part is the XLR connector (or maybe the LED if you want a really big one) and like 30 minutes of time. Easy enough project


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## Andy_Leviss (Mar 19, 2008)

Yup, you're spot on. LED and resistor between pins 1 and 3, and away you go.

Now, an extra credit project...can you sort out a way to wire it up with a flashing LED that flashes for a few pulses after the call button is released like some base stations do?


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## porkchop (Mar 19, 2008)

Two diodes, two capacitors and remembering freshman year of school yes. I actually made an applicable circuit, if you really want it I could look it up.


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