Wait to unplug with phantom power

Question

When I use a mixer (Behringer 4-track), the instructions say to wait about ~30 seconds after turning off the phantom power before unplugging anything. They say not doing that could damage the equipment.

Now I have an XLR-to-USB connection that provides phantom power (48V, like the mixer), and there's nothing about that in the instructions. Is it safe to unplug the mike right away?

score 5 · Answer 1 · answered Aug 28 '12 at 18:21

5

In general, if you unplug anything from a power amp, you could amplify small currents into a pretty loud pop...which could be enough to damage speakers or amplification circuits.

With phantom power, the problem is that when you unplug, the power to circuits is dropped quickly so you get current surges from inductors and capacitors, and these can be much higher than a simple pop.

So the recommended plan is:

mute the channel - ideally mute the input, rather than the output :-)
power down phantom power
unplug mics/DI boxes etc

answered Aug 28 '12 at 18:21

Rory Alsop

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With this, is there any chance of damaging the microphone as opposed to the speakers/other system components? – Sep 01 '12 at 22:21
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I have never heard of one being damaged this way - the amps/speakers would be the most likely as they amplify small signals up, so are very sensitive to large signals. – Rory Alsop Sep 01 '12 at 22:24
Alright that makes sense. – Sep 01 '12 at 22:25

score 0 · Answer 2 · answered Aug 28 '12 at 18:14

The only reason I can think of to have to wait before unplugging your mic is to allow any capacitors to drain. I don't believe this can take more than about five seconds. I have always waited about this long anyway since that's how long it takes me to reach up and grab the mic to pull the cable out after turning off phantom power. By convention I prefer pulling the cables out of the mic first, then the preamp.

Wait to unplug with phantom power

2 Answers2