# Phantom Power - How Does It Work?



## david henman (Feb 3, 2006)

...i use a combination of condenser and dynamic (shure) mics through the sound system when performing live.

the mixer has phantom power, but its either on or off for ALL mic channels.

do i turn the phantom power on, or leave it off?

cheers, and thanks!

-dh


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## Hamm Guitars (Jan 12, 2007)

I have had a few problems with a few brands of Bass amps (some newer Ampegs and the odd Yorkville as well as a few others - they all seem to be newer ~post 2001~ though ) over the past few years not liking phantom power on their direct outs. 

I'm not sure if they are not balanced correctly, or what the problem is but they will start acting up a few minutes after you plug in or turn on the phantom. The problem might also be the phantom power on Mackie mixers, as that is the only board that I use that doesn't have the individual channel phantom 'on' buttons. I've never bothered to get to the bottom of it as it was just as easy to turn off the phantom and go with all dynamics and passive DI's once I figured out what was going on.

Any way, if your bass player has an amp that doesn't like phantom, you will hear a clicking/poping noise with increasing frequency until it sounds like static - it is loud so you can't miss it. I've had a few that began to oscillate as well. The noise is comming out of the amp on stage as well as through the PA, as I've walked away from the board with the channel muted and it has caught me off guard once or twice.

In all cases, turning off the phantom power on the board makes it go away. You could also put a DI on the bass and that works as well.

Not suggesting that this will be a problem for you, but it is the only issue I've ever had concerning phantom power.


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## david henman (Feb 3, 2006)

jroberts said:


> On. It won't hurt the dynamic mics, and the condensors _need_ it. Just make sure you plug all the mics in before turning it on and turn it off before unplugging anything. Phantom can blow ribbon mics, but if they are modern ribbons and wired properly, even that shouldn't be a problem.


...thanks, jr. that is the answer i was looking for.

the bass guitar is not an issue at this time, as we don't feed it through the sound system. once we get a sub-woofer, that will change, of course.

thanks for the help, guys!

-dh


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## sysexguy (Mar 5, 2006)

The bass guitar is not a problem, it's if you use a an amp with a direct XLR out that may cause grief. Using a bass with an active DI (phantom power required in fact) will give excellent results.

I would recommend watching out for hooking up phantom power to a wireless mic's base station. With companies producing mic pre's for next to nothing these days, adding a rack or two of pre's for the condensors (or vice versa) if required, is a simple and effective way to separate the channels that shouldn't receive phantom from those that do......

Andy


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## BoogaBooga (Mar 1, 2009)

Dynamic mics don't (usually) have a problem with phantom power on. But if you have older mics, you might have to rewire the matching transformer inside, so double check. I know for a fact that modern mics don't have a problem with phantom power (you'll just hear a pop when you plug them in and out.. and its pretty loud).


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## ronmac (Sep 22, 2006)

Generally dynamic mics won`t have a problem (although there is a very slight change in frequency response) with phantom power, but if you have a choice keep it switched off. Older T-powered dynamics and ribbon mics can be destroyed by phantom power.

Plugging or unplugging mics or other equipment while phantom power is applied (hot-popping) can cause damage to the equipment.


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