Quote:
Originally Posted by thesilentdrummer
Dynamic mics have some circuitry that bypasses phantom, even if it is active.
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On a balanced cable you have three connections, hot, cold and ground. The audio signal uses hot and cold and the ground is used for cancelling any difference between the hot and cold, ie noise. Your dynamic can still work with just the hot and cold (you just lose the noise cancelling and drop some level due to reasons I won't go into). So they put the positive of the phantom, usually 48V dc, on both the hot and cold and the negative on the ground.
What this means is that the capsule of the dynamic gets 48V +ve on the hot and 48V +ve on the cold. As voltage is actually a measurement of potential difference, the difference between +48V and +48V is zero so the capsule does not see any phantom.
Picture it like two 48 storey buildings right beside each other. To walk from the roof of one to the other is no problem (providing there is no gap of course!) as they are at the same height but, if you walk off one of the buildings to the ground, you will fall 48 stories
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The condenser is wired to allow it to actually use the 48V.
This is one reason why good cables are so important. A miswired cable can give the dynamic mic 48V difference across the capsule and this can fry it.
If you are using phantom you should never plug in or unplug any input whilst live as the pins don’t all make or break at the same time so you can, inadvertently but momentarily, apply phantom to them. Plus if you do this you will normally get a big pop through your system.
Baron