Why not plug in a mic while phantom power is switched on?

[homerecorder123]

I keep reading that I shouldn't plug a mic into the console/preamp while the phantom power is switched on.

I can see how this might be detrimental to a condensor mic.

But the big question for me is, what about dynamic mics like the SM58? Can you do any harm to it if you do this?

By the way, I do know that phantom power itself shouldn't harm a dynamic mic.

Much thanks in advance.

(Edited for verbosity)

 

[DJL]

What does your console and preamp manuals say about this... I bet they say it's not a good idea and most likely goes into some small details why. Read your manuals.

 

[Blue Bear Sound]

Do you really need to be told it's not a good idea to plug/unplug a device from a cable that's providing 48 volts of electricity at its ends?

 

[Havoc]

Well, you do plug in all your equipment into a working 220V outlet don't you?

I always tought it has to do with both pins of the connector carrying 48V (pins 2 & 3) not making contact at the same time. Some mics use a transformer between pins 2 & 3, with a center tap that is used to take the 48V to the electronics. Now this transformer is made so that when the 48V is used, then the curent drawn through both halves does not magnetise the transformer. IF however, one pin should make contact without the other, then in only half of the transfomer would flow current, magnetising the transfomer, something that is not desired.

 

[homerecorder123]

DJL... dang, I knew I left something out. In fact I did read the manual over and over. It mentioned not to plug the thing in yadayada at least three times - but never said why! And I'm just a dude that gots to know why, hence my post.

Blue Bear Sound... well, yes I do, actually. Psst... (said in low whisper) you gotta understand that some of us are total idiots when it comes to electronics. Go easy on us - we're just trying to learn.

Havoc... cheers alot, mate!

(Edited for typos)

 

[billisa]

DJL... dang, I knew I left something out. In fact I did read the manual over and over. It mentioned not to plug the thing in yadayada at least three times - but never said why! And I'm just a dude that gots to know why, hence my post.

Blue Bear Sound... well, yes I do, actually. Psst... (said in low whisper) you gotta understand that some of us are total idiots when it comes to electronics. Go easy on us - we're just trying to learn.

Havoc... cheers alot, mate!

(Edited for typos)

Thanks for the question. The manuals I have just say don't, but not why... I always felt it was like plugging in an appliance with the power switch already on. But it's funny. Manuals often warn against using phantom power on dynamic mics, but others say it simply doesn't matter... (the juice never gets to the dynamic mic, or doesn't adversely affect it). So knowing why, in my view, is a good thing.