phantom power

[birdfeeder]

Newbie question here: I have run a search here but come up empty so here is my silly question.

I have just purchased a new camera with built-in XLR hook-ups on the camera. Reading the instructions for the camera I'm directed to turn a switch on or off depending on whether or not the mic's have "phantom power". I am using battery powered Sennheiser lavaier mic's. Are the batteries that power the microphone's considered a "Phantom power"? Or does Phantom power only come from something that is plugged into a wall socket and converted to DC to power a microphone?

[guns1inger]

Phantom power means the power is being drawn over the mic cable itself - think USB powering a webcam as well as carrying the image data. If you are using batteries in the mic then you don't need phantom power. I would suggest using phantom power if you are running the camera off mains, and using the mic batteries if the camera is running off batteries.

[edDV]

Check first to see if the Sennheiser lavaier mic accepts phantom power. Most don't. If not, don't turn it on at all. There is a possibility of damage.

[birdfeeder]

Thanks for the info guys. This is what I come up with;

First--EdDV all I can find in the Mic's information booklet is that it states "you can connect a PA system or a recording unit (e.g. video camera) to the body pack receiver" (obviously, as i have them hooked up to the camera). I have the receivers attached to a "Y" bracket that slides into the hot shoe of the camera . This bracket holds 2 receivers.

Second--The Camera instructions state, "To supply a microphone with phantom power, set the corresponding +48v switch to ON" "make sure to connect the microphone first, before turning the phantom power on. Keep the microphone connected when turning off the phantom power. I realize these are precautions to prevent a static discharge that can damage the camera or the mic's.

If these microphones run on 2 AA batteries for the transmitter (pick-up mic) and transmits to the receivers on the camera that also runs on 2 AA batteries -(to receive) and the corresponding audio is recorded to tape via the XLR cables this all seem like low voltage stuff here to me and I would therefore assume that this is not declared a "phantom power" and would want to switch the cameras "phantom power" swithch to off.

Or guns1inger as you state "power being drawn over the mic cable itself", does this battery power powering these units make it a phantom power?

Hope this makes sense.--thanks

[Steve Stepoway]

Remember that phantom power is supplied by the recording device, and is not something that mics "have" or "don't have"; it's something that they either "need" or "don't need". If the wireless receiver has batteries in it, then it's highly unlikely that it needs phantom power (I've never seen one that did). A condensor mic hard-wired into your camcorder would likely need phantom (unless it had a battery in it). Unlikely that anything else would.

Steve

[edDV]

If these microphones run on 2 AA batteries for the transmitter (pick-up mic) and transmits to the receivers on the camera that also runs on 2 AA batteries -(to receive) and the corresponding audio is recorded to tape via the XLR cables this all seem like low voltage stuff here to me and I would therefore assume that this is not declared a "phantom power" and would want to switch the cameras "phantom power" swithch to off.

I agree. Keep phantom power off. Wireless mics almost never run off phantom power and the 48VDC could damage the mic receiver.

Phanom power is usually used with wired pro condenser mics.
http://en.wikipedia.org/wiki/Phantom_power

[birdfeeder]

Ok guys thanks. I have hooked up and tested the Mic's and everything is good to go. The mic's work amazingly well. I'll be back with more questions i'm sure.