phantom power???

Logan Wilkerson · Post by **Logan Wilkerson** » 30 Dec 2004 11:51 pm

hello everyone i was just wondering if anyone could tell me how i get phantom power to go through my tt cable patchbays. i have a 5 room studio that has xlr conectors in each room in the wall. hat are all ran to four tt patchbays. thanks all help will be very appreciated!

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sho-bud proII custom
session 400 b/w series
american deluxe tele

Dave Boothroyd · Post by **Dave Boothroyd** » 31 Dec 2004 1:49 am

I don't understand what you mean by tt patchbays.
If your studio is wired with balanced cabling to XLR connectors, anything which is connected to a desk input which is powered with 48 volts will receive phantom power.
It sounds as if you are running balanced inputs through an unbalanced patchbay. Is it a jackplug patchbay or an XLR one? If it's a Jackplug one, are the jacks TRS (tip ring sleeve) or plain ones like a guitar jack?
Tell us more!

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Cheers!
Dave

Paul Osbty · Post by **Paul Osbty** » 31 Dec 2004 3:03 am

Also, do not run phantom power through TRS plugs (stereo 1/4"). It's just way too easy to short it to ground. Mixing boards only supply phantom to the XLR's, so don't use adapters to convert.

Keep the phantom power on the XLR's.

Paul Osbty · Post by **Paul Osbty** » 31 Dec 2004 3:15 am

Look at the bottom of this page.
http://home.flash.net/~motodata/patchbays/faq.html

You had best get some info from the manufacturer of that patchbay. Some of the TT's are phantom capable, but some need to have grounds strapped and such. I'm not sure about those bantam connectors.

Good thing you ask questions first, though!

Dave Grafe · Post by **Dave Grafe** » 31 Dec 2004 11:57 am

Paul has some good suggestions. Professional TT patchbays are balanced, i.e. TRS and as such should pass phantom power with no problems. As noted above, shorting can be an issue so be sure that your patching is in place BEFORE you turn the +48v on.

If you somehow have not got TRS gear OR if your grounds are not connected throughout (or if either side of your signal line is connected to ground as some input transformers are) it won't work and could damage your power supply.

Television remote trucks run phantom power to the field using TT style TRS patchbays all the time with very few problems.

dg<FONT SIZE=1 COLOR="#8e236b"><p align=CENTER>[This message was edited by Dave Grafe on 31 December 2004 at 12:02 PM.]</p></FONT>

Blake Hawkins · Post by **Blake Hawkins** » 31 Dec 2004 1:58 pm

The folks who designed the phantom power system for microphones realized that it will probably get shorted at some point.
Therefore all properly designed phantom power supplies for microphones are current limited.
You can short them without doing any damage to the power supply.
So don't worry about a TRS plug with phantom power.
Of course it is always good practice to turn off the power when connecting and disconnecting the equipment.
However, if you forget or the system is set up so you can't do that, you probably won't hurt anything.
Note that phantom power is only for balanced microphone circuits. If you connect an unbalanced dynamic microphone you could burn out the mic element.
Also, don't mix balanced and unbalanced lines in a patch bay.
Blake