What happens if you run phantom power into a cardoid mic?

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I'm talking an sm-57. I have 2, and I wanted to get 2 mxl condensers to use for vox/drum miking, and I'm not sure if my Tascam US 600 interface can select which tracks use and do not use phantom power.
 
I'm talking an sm-57. I have 2, and I wanted to get 2 mxl condensers to use for vox/drum miking, and I'm not sure if my Tascam US 600 interface can select which tracks use and do not use phantom power.

Just for clarification, cardoid is the polar pattern of the mic, however, it is not the "type" of mic. A SM-57 is a Dynamic mic....But regardless, typically you can send phantom power to a dynamic mic and nothing will happen. I have actually done this as my profire 2626 only can send phantom down channels 1-4 or 4-8 and when I record drums I sometimes mix and match and end up sending phantom to dynamics. Typically, however, phantom will not affect a dynamic at all.

On the other hand, for the most part, you should NEVER send power to a ribbon. That = Bad News.
 
So long as you're using properly made XLR cables (i.e. balanced) connections, then phantom power will not hurt your SM57 (or any other decent mic) at all. Phantom is specifically designed so any balanced mic that doesn't need it can simply ignore it.

(A bit of physics for those who are interested: phantom provides the same DC voltage on both live legs of your cable. Once it arrives at your microphone, the polarity of one leg is inverted, totally cancelling out the voltage.)

Even the "phantom kills ribbon mics" story is largely a myth as detailed HERE.

However, a couple of cautions. First, it's a bad idea to plug any cable in when the phantom is turned on. At best, it can cause nasty pops on your monitors which could damage a driver and, should one of your cables be faulty, it's possible for one leg to make contact slightly before the other sending a brief burst of phantom where it shouldn't go. Always do all your connections, then turn on the phantom.

Second, never use adaptors to feed something unbalanced into a phantom power source. That WILL kill gear.l
 
So long as you're using properly made XLR cables (i.e. balanced) connections, then phantom power will not hurt your SM57 (or any other decent mic) at all. Phantom is specifically designed so any balanced mic that doesn't need it can simply ignore it.

This is not quite true!

It is correct that 48V phantom power will not damage a dynamic mic. that is balanced and the cable from the mic.is also fully balanced. So it won't hurt your SM7.

But it is NOT correct to say that phantom will not damage "any other decent mic".

Phantom can seriously damage many ribbon microphones and it's also possible to damage a mic. designed for 12V T (AB) powering.
 
Okay. Make that any "modern" microphone with balanced connection. My old Sennheiser 415 used AB power but I haven't seen anything using that system in a couple of decades. In any case, a few accidental doses of phantom (my old Audio Developments field mixer could provide either) never actually damaged my 415 which was retired gracefully and sold on eBay.

As for ribbon mics and phantom, that problem is hugely over-blown and, where there are problems, it's generally down to patchfields or faulty XLRs that make one leg before the other...and this apples to ANY microphone, hence my caution about never patching any mic with phantom turned on.

For reference, here is Royer's (the maker of probably the best ribbon mics on the market) take on the issue of phantom power: RIBBON MICS AND PHANTOM POWER.
 
Okay. Make that any "modern" microphone with balanced connection. My old Sennheiser 415 used AB power but I haven't seen anything using that system in a couple of decades. In any case, a few accidental doses of phantom (my old Audio Developments field mixer could provide either) never actually damaged my 415 which was retired gracefully and sold on eBay.

As for ribbon mics and phantom, that problem is hugely over-blown and, where there are problems, it's generally down to patchfields or faulty XLRs that make one leg before the other...and this apples to ANY microphone, hence my caution about never patching any mic with phantom turned on.

For reference, here is Royer's (the maker of probably the best ribbon mics on the market) take on the issue of phantom power: RIBBON MICS AND PHANTOM POWER.


^^^^THIS^^^^

Ribbons are only damaged from phantom power when a short is created.

This video shows a GREAT demonstration

 
Aside from all the small exceptions and rare opposites to the rule, far as the OP is concerned, I would just say stick the rule of avoid phantom power to ribbons...
 
Well, since the original question was about an SM57, I think all this debate is pretty academic anyway.

However, I'd say the more important rule is "never plug or unplug ANY microphone while phantom power is switched on". A patchfield using any form of jack, or even an XLR with one pin pushed farther in than the other can result in one leg connecting before the other and this is the biggest risk in phantom power. Once all the connections are made, turning on the phantom shouldn't affect any current microphone (ribbon, condenser or dynamic) with a balanced output.

As John Willett pointed out, there are some much older designs where phantom could be an issue--but these are not models that many people on HR are ever going to see.

Since so many mixers and interfaces have a single "global" switch for phantom, trying to stick to an unnecessary rule of "avoid phantom" could be pretty limiting.
 
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