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Author Topic: DMX cable usable for mic or line level?  (Read 7351 times)

Randall Hyde

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Re: DMX cable usable for mic or line level?
« Reply #20 on: February 14, 2015, 01:47:36 am »

If I ever see someone trip on the cables, I'll tape them down.  Until then, why waste $20/roll gaffer tape?
Because that's the *professional* and *responsible* thing to do. Most venues I work out would never let me leave uncovered cables in foot traffic areas.

For those who don't want to pay $20/roll for (2") gaff tape (and I typically use 4" tape at $35/roll), here's a solution I use: buy up a bunch of rubber carpet/matts at Home depot (about $20 for a 3x5' matt). Lay them out over the affected area. Tape down the corners. Less of a trip hazard than cable guards and certainly less expensive. Of course, you can't drive over them (without damaging the cables underneath) but for foot-only traffic they work great. They wear out after a couple of years in the sun but are otherwise a pretty good deal.


Quote
Seriously, I get yelled at for having a few seconds of delay with Luminair.  How does one get away with glitches in a live show, in-house or not?  I mean what explanation would you use?  Blame it on the cable that was supposed to be tested before?
:)
Reminds me of the days when I thought wireless DMX was a good idea.
Cheers,
Randy Hyde
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Mac Kerr

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Re: DMX cable usable for mic or line level?
« Reply #21 on: February 14, 2015, 02:25:31 pm »

Note that pin one is tied to the shield on audio cable. Not true on DMX. This arrangement will blow up some DMX fixtures (Blizzard, I'm talking about you).
I used to have a whole bunch of generic XLR cables mixed in with my DMX batch-- Aft6er blowing up several fixtures, I got and Ohm meter out and pared the lot down to pure DMX.

What exactly do you mean by this? Pin one should always be connected to the shield, in DMX or standard audio cables. The DMX specification says that pin one should be connected to electrical ground at transmitter outputs (consoles and controllers), but have a high impedance connection to ground at receivers (lights). Audio cable should have pin one connected to shield at both ends so the shielding continues for the length of the cable run if multiple cables are used. Pin one should not be connected to the XLR shell in either case.

Mac
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Randall Hyde

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Re: DMX cable usable for mic or line level?
« Reply #22 on: February 14, 2015, 02:45:10 pm »

What exactly do you mean by this? Pin one should always be connected to the shield, in DMX or standard audio cables. The DMX specification says that pin one should be connected to electrical ground at transmitter outputs (consoles and controllers), but have a high impedance connection to ground at receivers (lights). Audio cable should have pin one connected to shield at both ends so the shielding continues for the length of the cable run if multiple cables are used. Pin one should not be connected to the XLR shell in either case.

Mac

Tell that to Blizzard.
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Lee Buckalew

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Re: DMX cable usable for mic or line level?
« Reply #23 on: February 14, 2015, 04:15:41 pm »

Tell that to Blizzard.

Real DMX cables are wired pin 1 to shield at both ends, Pin 2 Hot at both ends, pin 3 cold at both ends.  The only difference in cable between DMX and analogue line level/mic level audio is impedance.
Now, if you mean pin 1 should not be tied to case ground by connecting the connector she'll to pin 1, that is true.  If the equipment manufacturer wants pin 1 and case grounded (or not) they need to do that (or not) inside the chassis.

Lee
« Last Edit: February 14, 2015, 04:18:02 pm by Lee Buckalew »
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Lee Buckalew
Pro Sound Advice, Inc.

ProSoundWeb Community

Re: DMX cable usable for mic or line level?
« Reply #23 on: February 14, 2015, 04:15:41 pm »


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