Can phantom kill a dynamic??

[buzzaudioguy]

So a couple of months ago one of my D112's died at the end of a live set I was recording. I was using a pair of Firepods. The phantom powers up in groups of 4 and I happened to have the D112 plugged into one group that was active. Now, I've run mics before on boards with phantom that was basically on or off for all channels, and I've never killed one of my dynamics. I've never liked the idea, and I've always heard and or read it wasn't the best idea, but can you actually kill a dynamic that way? I'm just wanting to know if anyone else thinks it's happened to them or if it's even possible. If it is, why the hell doesn't EVERY manufacture make phantom selectable on every seperate channel!

[JGriffin]

why the hell doesn't EVERY manufacture make phantom selectable on every seperate channel!

money.

[A-Barr]

I think if the mic has a transformer (SM57, SM58) it will "ignore" the +48, but if it doesn't (SM7B) the voltage will be sent right through the capsule. Remember that a dynamic element is basically a little tiny speaker hooked up backwards. So what happens when you run DC through a speaker? Instead of pushing and pulling the cone/coil back and forth as it does with AC, it'll just push and with a lot of voltage it could push hard enough that it could tear the cone or the foam or push the voice coil all the way out, I think it could also overheat the voice coil till it melts the insulation and shorts out.
I agree, that is LAME to not have individually selectable phantom! It saves them money, I guess, but come on, all you need is an SPST switch per channel, that's like a $2 part!

[lyman]

i'm a total space cadet and often throw a dynamic mic into a pre-amp and forget to switch the phantom power off. it's never ruined a mic so far(knock on wood).

[bluesman]

I use dynamic mic's all the time without switching off the phantom power. I have never lost a dynamic mic to phantom power yet.......drum sticks yes, phantom power, No.

[ToddP]

I think if the mic has a transformer (SM57, SM58) it will "ignore" the +48, but if it doesn't (SM7B) the voltage will be sent right through the capsule.

It isn't the transformer, it is the balanced signal that makes phantom power is invisible to any dynamic that is correctly wired. It has been known to hurt ribbon mics that were not wired correctly, or had bad cables connected to them. I would not suspect phantom power as the culprit in this case however. What makes you suspect it?

[wesimel]

so if i do a tape op mod to my 57, and run phatom power through it, it will bust the capsule?

[A-Barr]

It isn't the transformer, it is the balanced signal that makes phantom power is invisible to any dynamic that is correctly wired

Ahhh, ok, that makes sense. If you're putting +48VDC on the + and - terminals of the capsule, there is no voltage difference so the DC does not run through the capsule!

[philbo]

It isn't the transformer, it is the balanced signal that makes phantom power is invisible to any dynamic that is correctly wired

Ahhh, ok, that makes sense. If you're putting +48VDC on the + and - terminals of the capsule, there is no voltage difference so the DC does not run through the capsule!

Yup. The only way this might kill a capsule is if one side of the capsule is grounded by deteriorated insulation or maybe being mis-wired. (OK, there might be other ways... )

[buzzaudioguy]

I think if the mic has a transformer (SM57, SM58) it will "ignore" the +48, but if it doesn't (SM7B) the voltage will be sent right through the capsule.

It isn't the transformer, it is the balanced signal that makes phantom power is invisible to any dynamic that is correctly wired. It has been known to hurt ribbon mics that were not wired correctly, or had bad cables connected to them. I would not suspect phantom power as the culprit in this case however. What makes you suspect it?

I don't suspect it so much as I just wanted some other opinions. I've never had anything like this happen before but I always wondered if something like this might happen. So when the mic died it just made me think. Point is I don't want to fry any more mics if indeed it is due to phantom power, but it sounds like this isn't the case. I do know to watch it with ribbons, but aside from that I think I won't sweat it next time I have to plug another dynamic into a hot channel. Thanks!

[DaViDB112]

You should open the mic up and check that capsual . i have never lost a microphone , dynamic that is , through the use of phantom power.

[Professor]

I agree, that is LAME to not have individually selectable phantom! It saves them money, I guess, but come on, all you need is an SPST switch per channel, that's like a $2 part!

True enough, but remember that the average price structure in the audio world is 3x parts cost equals dealer cost and 5x parts equals MSRP. So a $2 part means $10 more at MSRP across maybe even just 4 channels means $40 more and that means somebody buys the Behringer board instead. That's the same reason meters leave the boards quickly even though they are so essential, especially for novice users.

As for the phantom power killing a D-112, I would really doubt that. If it could have possibly done so it would mean there was something wrong in the wiring that caused a short or something - in which case the short killed the mic.
My guess would be that there was a weak/loose/cold solder joint inside that broke off, or the transformer was bad and shorted internally, which wouldn't harm the mic capsule but would shut it down.

Phantom does, however, have the ability to kill ribbon mics dead.

-J

[swishniak]

[quote="A-Barr"]
Phantom does, however, have the ability to kill ribbon mics dead.
-J[/quote]

yeah - apparently neither dynamics or ribbons should be affected by the phanton power (thats what that 3rd little prong is for?) but shouldnt actually be plugged into a phanton powered strip. at least according to most manuals i've read.

ive always been way more careful with my ribbon than with dynamics - but this makes me think..

i guess thats why they call it phantom - lurking there, waiting for an unsuspecting victim.

[Judas Jetski]

Who knows what evil lurks in the hearts of men (and their consoles)? No, wait. That's the Shadow. Sorry.