How do I know if a dynamic microphone is balanced or not?

[mge]

Hi all,

I was wondering how I can tell if a dynamic microphone is balanced or not?  I've been reading the manual for a mixer board that I am looking at buying which can provide phantom power on all the mic inputs or none of them.  Since this is for a home studio setup I'll be using some dynamic microphones and some condenser microphones.

I know that you shouldn't apply phantom power to unbalanced dynamic microphones but I'm not sure how I tell if a specific dynamic microphone (for exampe Shure SM57s) are balanced or not.  I would guess that any dynamic microphone that uses XLR is balanced, but I don't want to be wrong here.

How can I tell?

Cheers!

[rokpunk]

don't worry about phantom when using dynamics. phantom will have no effect on the mics. different story if you are using ribbon mics, but chances are, you aren't.
as per your balanced question, your xlr cable is balanced.

[John Willett]

don't worry about phantom when using dynamics. phantom will have no effect on the mics. different story if you are using ribbon mics, but chances are, you aren't.
as per your balanced question, your xlr cable is balanced.

Sorry - not quite true.....

The dynamic microphone must be balanced - then phantom is no problem - if it's unbalanced you will short out the phantom power.

You are correct about ribbons, of course.

Things like the Shure SM57 and 58 *are* balanced.

[mge]

Things like the Shure SM57 and 58 *are* balanced.

Thanks John.  Is there any hurisitc to figuring out if other mics are balanced or not (another Mic I was looking at was the AKG d112).  Will providing phantom power to an unablanced dynamic microphone damange the mic or just make the recording sound bad?

[Church-Audio]

Things like the Shure SM57 and 58 *are* balanced.

Thanks John.  Is there any hurisitc to figuring out if other mics are balanced or not (another Mic I was looking at was the AKG d112).  Will providing phantom power to an unablanced dynamic microphone damange the mic or just make the recording sound bad?

The only way to know for sure is to open the mic up and see if there is a transformer if there is a transformer inside the mic its balanced. Now that being said most dynamic mics do not have a transformer they simply use the negative side of the dynamic capsule to pin 3 and the positive side of the capsule to pin 2 and the shell to ground pin 1. Shure sm 58 and 57 are microphones that have balancing transformers. So I am pretty sure the AKG d112 is not actually a true balanced microphone. I know the D12 does have a transformer. AKG was hit and miss some of the cheaper mics did not have the transformer some did. Most companies use the transformer as a means of "stepping up" the output of the capsule and providing a good load to the capsule as well as isolation. even if the mic does not have a transformer as long as pin 2 and pin 3 are connected to the capsule it will not short out the phantom supply. The problems arise when some cheap mics short out pin 3 to ground. Then you have a real problem. I think if your mic does not need phantom is should be off.. If you cant turn it off the AKG mic will not DAMAGE your phantom supply and your phantom supply will not damage your mic. So use it as you normally would.

Chris

[John Willett]

(another Mic I was looking at was the AKG d112).

Yes, this is balanced.

[ghellquist]

Simply ask. John knows a lot about mics.

The nice thing about phantom power is that when the mics, cables and pre amps follows the specs you can freely mix and match dynamic and phantom powered mics with no side effects. If it has an XLR mic connector you can be pretty certain it will work. Generally, only very old or very specialized or very cheap mics will not mix and those I´ve seen has different types of connectors.

Gunnar