http://en.wikipedia.org/wiki/Phantom_power

By the way, CClub, when you read specs related to mics (including your Rode, probably), "48v" is also known as "phantom power"... just for info.

You all are life savers. Just so summarize: so in other words, if I have any mic and it has a battery or some version of its own power source, it doesn't need additional "phantom power" and I'd always switch the +48V off? I'm assuming it'd also be self-evident, as the sound level would be too high if I have a battery power source or soundboard power AND I switched the +48V to ON, correct?

Additional isn't where it is at. Power is normally mutually exclusive in where you can bring it in from, afaik.

It should be self-evident if you stick to the convention of leaving phantom power turned off on your camcorder whenever you plug something you are not entirely familiar with in. If it needs power - you will likely not hear a bleep out of it. Always confirm whether there is a transformer in the mic to extract the phantom supply.

It really isn't about whether the signal from the mic will be too hot. It isn't like an impedance matching element. What you are ensuring is that you don't break the mic or worse, the 48V feed/source out of the camera. The phantom regime should prevent this but when a mic is upwards of $100 and a camcorder is upwards of $4000, why risk it by 'plug and play' accidents. Depending on how the mic is designed, you could be attempting to charge a non-rechargable battery with the equivalent of a 39V charger. Probably not, but special effects is unlikely to be the intention of this mic being used!

Balanced mixers can be handy if you've got much of this uncertainty going on. Then if you stick to the same mixer, you can be sure of what you are sending to your camcorder, and you may be able to record a second version to another audio-only deck too.

To the best of my knowledge the Videomic cannot be powered from phantom power, it doesn't have balanced outputs and without that phantom power just isn't possible.

I don't know about the lav mics, check their specs.

The Rode NT3 and M3 mics let you have it either way, 9V battery or phantom power, no need for switching anything and in general given the choice between phantom power or a battery in the mic, phantom is a better choice. After all having to change a battery in a mic during an event is not a good look and some mics perform slightly better off phantom power than battery power, assuming the phantom power supply is a good one and not all are.

One down side to using the Videomic through the minipin to XLR adaptor if you left the phantom power on is it's quite likely the adaptor grounds one side of the XLR which means the phantom supply in the camera will be feeding a bit of current into a short circuit. I very much doubt anything will fry but you're wasting camera battery power.

Bob.

Bob.

Amen Bob. A properly designed phantom power supply will not damage any non-phantom powered microphone plugged into it. As far as self-powered [battery] microphones, that's for use when phantom power just isn't available. If you have phantom power available, always use it. The 48V will extract the best performance from the microphone, something the built-in battery power supply will not.

All good comments. I've seen a lot more manufacturer warnings about phantom power in the last few years as ribbon mics have had a resurgence. Some of these can be destroyed by phantom power.
Also I have seen lavs with button style batteries that can run off the battery OR phantom. If you leave the battery in AND use phantom the battery will swell and explode.

Just fair warning!

Jesse