Phantom power question

[PaulLePine]

Bob W. or other experts,

Fundamental question for this recording newbie: My mixer can supply phantom power, but does it for all channels or none. I have some vague recollection that I should be concerned about supplying power to those channels that don't need it. Have NEVER worked with a condenser mic before, so never had to turn the 48v on. Is there an issue? ALL instruments on the board go through a DI, if that helps; NONE of the dynamic mics do.

FYI... my pastor and I want to do some rough recordings of some praise & worship music he's written; nothing polished, but decent enough to give away as aids to people learning the music.

Based on Bob's glowing plug of the Marshall 2003, I bought it's cheaper cousin (1006) for $80 at Sam Ash (special sale.) Yeah, I know it's not the same mic as the 2003, but for $80 I figure I can't go wrong for a "learner's" mic!

TIA...

~ Paul

[Warblade]

Hey Paul,
From what I know, phantom power won't affect other instruments/mics that don't need it. So even with the phantom power turned on and say you have some shure beta 58 in there (which doesn't use phantom power) it won't mess with it or fry it's circuits or anything. =)
Oh, and most mixers supply phantom power to all XLR channels. I believe it's only through the XLR connections too.
Randall

[kenliu]

If you want a definitive answer, you should try the churchsoundcheck discussion group. http://www.churchsoundcheck.com

There are a lot of professionals as well as volunteer church A/V guys on the list. They are very helpful and friendly. The list is kind of geared toward live church sound, but it's still an excellent resource if you're getting into recording.

Ken

Ok, I'll ring in on this.

Here's the "golden ears" answer to your question: According to those who claim to have hyper-acute hearing, dynamic mics should not be placed on mic channels which have phantom power because the first time you do it, the mic's response is permanently changed.

My response? Mmmm... I've never heard the change myself. Having heard this theory early in my career, I've studiously avoided doing it but haven't heard a change when it has occurred accidently. What you are doing is placing 48 volts at low amperage across the output of the mic. The only potential I could see would be a slight magnet re-alignment of the permanent magnet in the capsule from the influence of creating an electromagnet in the coil. I still avoid putting P48 on a dynamic. The easiest ways to do this are using a console with individual P48 select or bucket-by-bucket P48 select, or by switching it off entirely and using individual or multiple outboard supplies.

Does this help? Could I confuse you further?



Bob

[ 05-21-2001: Message edited by: Bob Womack ]

[PaulLePine]

Hey, thanks! That does help, and isn't TOO confusing. In the meantime, I found some docs that suggested it's OK to send power to dynamics IF you're using balanced connections, which I am. So I tried it, and nothing terrible happened. If I changed the response of the mics, I can't hear it; but the acoustic space is so challenging that it would have to be REALLY profound to be noticeable!

Thanks!

~ Paul