will phantom power hurt a mic that doesn't need it?

P

Phil

New member
my sound card has 4 inputs. I have one mic that needs phantom power and three that do not. When I turn on phantom power on the breakout box phantom power is delivered to all 4 inputs. Will the phantom power hurt the other three mics or cables at all?
Thanks.
Phil
 
I've heard phantom power will destroy a ribbon mic. I've used phantom power with my dynamic mics (Shures) and haven't noticed any difference, not even a boost, which would be nice, actually.

[This message has been edited by dobro (edited 02-08-2000).]
 
phantom power will not hurt any of the current models of dynamic mics, so you should not have a problem mixing them in with the condensers that do require it. however, your outboard phantom power unit should not be applying voltage across any of the other inputs, so i find that point a bit confusing. at any rate, the only mics which you will not want to use in that setup are ribbon mics - they can be easily blown by improper use with phantom powered systems.
 
I'm not using an outboard mic preamp or anything, I'm using the new Aardvark Direct Pro soundcard. It has 4 xlr inputs in the breakout box and a button that turns phantom power on and off across all four inputs.
I guess it should be no problem then since all I have is a condenser and a couple of shures. I don't even know what a ribbon mic is so I won't worry about it!! LOL
 
SilentSound said:
Actually phantom power in a ribbon mic is like giving a fuse too much juice it just pops!! In a very very bad way.
Click to expand...

A ribbon mic myth...
It's only if your mic cable is wired incorrectly, or someone switched the wires in your RCA 44BX, will there be a problem with applying phantom power to a ribbon mic...
It's just generally not a good idea just in case someone got their wires crossed, but with correctly wired cables it's not a problem...
 
yeah, only ribbon mics not wired fully to spec (read: many older mics) wlil be destroyed. some older dynamics *might* be hurt or get noisy, but with anything modern, don't sweat it. newer ribbons are okay too.
 
Will phantom power damage dynamic or ribbon mics?

When you switch on phantom power in some mixers, phantom is applied to all the mic inputs at once. What will happen if you plug a dynamic or ribbon mic into one of those inputs? Will it be damaged by the phantom powering?

Not if the mic has a balanced output, and is wired correctly. Even if the mic is a dynamic or ribbon type, phantom will not hurt the mic.

Phantom powering applies a positive voltage to pins 2 and 3 in the mic, and the ground of the phantom supply is connected to pin 1. In a condenser mic, pins 2 and 3 are wired to the circuitry inside the mic. Phantom current entering pins 2 and 3 goes through the mic circuit, then exits out pin 1 and returns to the supply ground.

In a dynamic mic or ribbon mic, pins 2 and 3 are wired to the mic’s voice coil or ribbon. Normally, the coil or ribbon is floating from the pin 1 ground. So the circuit loop to and from the phantom supply is incomplete. No current can flow through the mic’s voice coil or ribbon if you apply phantom power. Result: no damage.

On the other hand, if one end of the voice coil or ribbon is accidentally shorted to ground inside the mic, several milliamps of current from the phantom supply will flow through the voice coil or ribbon back to the ground of the supply. This current can deform the ribbon or immobilize the mic diaphragm.

In short, if the mic has a balanced output in which the voice coil or ribbon is NOT connected to mic ground, phantom will not damage the mic. If the mic has an unbalanced output because the voice coil or ribbon IS shorted to mic ground, phantom could damage the mic.

Hope this helps...

Bruce Bartlett
Mic engineer

[Edited by Bruce Bartlett on 08-11-2000 at 12:37]
 
Clear, concise and useful, yes. You've put an end to a whole lot of speculation, here, you understand. :)
 
And resurrected by someone whose signature looks very much like spam....

Oh, and there's at least one other username that also did the same thing in another post with similar spam in the signature and a similarly inane post.

Thread reported.
 
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