Topic: Changing mic capsules with 48v on

[larsrindsig]

Just for the record: you're not meant to do that, right? (I haven't, mind; just checking here )

[JasonSobel]

yeah, pretty sure that's a bad idea.

[dnsacks]

ditto with plugging in/unplugging xlr connectors

[audBall]

It does sound like a bad idea, but can someone explain why?  To me, it seems that power is either going to the mics, or it isn't. 

I always make sure my phantom is off before I turn my pre on/off while mics are plugged in, but that moreso a habit now.

[Church-Audio]

A regular electret capsule will not be damaged by doing this, if it is two wire low voltage 1.5 to 10 volts. Even with 48volt phantom most mics only see 10volts. It is the same as unplugging a two wire electret mic from a  battery box. The danger is with three or more contact mics that use more then 10 volts bias, they can be damaged due to the high voltages. The only real danger with most capsules is the huge pop created by this act, to the input of your preamp. Because such a spike can damage the opamps in the mic pre. So yes you can do it in most cases with no damage but, You always have to be carefull with the mic preamps input section. Its generally not a good idea. The other danger is shorting out the mics power supply and frying the mics preamp.

Chris Church

It does sound like a bad idea, but can someone explain why?  To me, it seems that power is either going to the mics, or it isn't. 

I always make sure my phantom is off before I turn my pre on/off while mics are plugged in, but that moreso a habit now.

[audBall]

Thanks, Chris.

[Church-Audio]

Not many mics use 60 volts they use +200 or +150 or 10v but not to many mics use +60 And many professional "real" mics use 10volts. Including Neumann

It does sound like a bad idea, but can someone explain why?  To me, it seems that power is either going to the mics, or it isn't. 

I always make sure my phantom is off before I turn my pre on/off while mics are plugged in, but that moreso a habit now.

Because REAL recording gear sends 60 MUSICAL F'n VOLTS to the caps.  That's why!

SIXTY!

Can you imagine if you touched your tongue to that?


That's right.. it would taste SPITTY ;-)

Now imagine how your caps feel.

You don't want 60 MUSICAL F'n VOLTS getting shorted into your mic buffer circuit, pre amp, etc.

[Church-Audio]

Got ya

Not many mics use 60 volts they use +200 or +150 or 10v but not to many mics use +60 And many professional "real" mics use 10volts. Including Neumann

Actually... Most schoeps polarize the capsules to 60 volts.  Many/most Neumanns too. I haven't measured the MGs.

But that wasn't really the point of my original reply ;-)

[Steve J]

But that wasn't really the point of my original reply ;-)

 

[Massive Dynamic]

The only real danger with most capsules is the huge pop created by this act, to the input of your preamp. Because such a spike can damage the opamps in the mic pre. So yes you can do it in most cases with no damage but, You always have to be carefull with the mic preamps input section.

On a related note, is it bad to change patterns of a multi-pattern mic while powered up? I've done this with my LSD2, so I was hoping this was different.

[Church-Audio]

Most mics are fine with changing the pattern U47 tube AKG414 solid state most mics are 100% ok to change patterns while they are on ( that way you can hear the difference the pattern makes

The only real danger with most capsules is the huge pop created by this act, to the input of your preamp. Because such a spike can damage the opamps in the mic pre. So yes you can do it in most cases with no damage but, You always have to be carefull with the mic preamps input section.

On a related note, is it bad to change patterns of a multi-pattern mic while powered up? I've done this with my LSD2, so I was hoping this was different.