Leaving phantom power on after turning off preamp

I've talked to a few people about this but haven't got a clear answer. What's the possibilities of damaging a mic by leaving phantom power on when powering off your preamp? Is it more of a cautious thing to turn it off before preamp for your monitors or can it damage the mic? Hope someone can clear this up, thanks!

I turn on phantom power after plugging in mic cables but I turn it off before unplugging mic cables. I'd unplug the mic cable before turning off the main power of anything that it's connected to. I do this even for preamps that have protection in place according to their spec.

You usually don't want to be plugging anything in or turning anything off or on (meaning main power supplies) while your monitors are live or while something is routed into the monitors, due to potentially damaging signal levels. I'm not sure if that's what you're asking. I don't think leaving phantom power on or off matters much to the preamp when turning it on or off, but I personally wouldn't leave mics plugged in when powering on/off a preamp. The potential for damage due to phantom power has more to do with the connector, mic and preamp design, likely. Turning on a preamp with a mic connected to it, even with phantom power engaged shouldn't damage it...unplugging it or plugging it in while the phantom power has already been on is what has, in theory, the potential to damage the mic or pre. Other people may have other valid practices or even theories as to why it should be done differently.

Undertow wrote:I turn on phantom power after plugging in the mic, but I turn it off before unplugging the mic. The potential for damage due to phantom power has more to do with the mic components.

I altered your quote a little to fit what I've practiced for years.

Here is an interesting video I found that kind of touches on why I mention connectors being more of a factor. In rare occasions such a connection fault can ruin a pre also. I realize this was meant to be a simple question about possible preamp damage, so I removed the details in this post that started to veer off into theory and shit. Do know though, mpc, most microphones that are designed to be used with phantom power (and even most that aren't) contain resisters or transformers (and obviously phantom power is DC)...so most won't be affected. Hopefully ribbons (just in case, though many will be OK) and externally powered mics were totally out of the equation, as I assume you were asking about preamp damage, not mic damage. Either way, good practice is good practice.

Sorry for going slitley off topic, but I do feel that my question kinda fits in this thread.

I tend to be very carefull with these things, and some people tell me not to shit my pants over it. But I rather being too cautious than ending up with **** up equipment.
Meaning ; I do all the plugging before I switch the power on. And I switch the power off before I re- or de- plug anything.
So here's my question;

Is it in any situation OK to plug or unplug a device from another while power is switched on??
If yes in which case and in which case is it an absolute NO.

Thanks for replys

-niN wrote:some people tell me not to **** my pants over it.

I'd tell you the same thing. 99% of gear made in the last 3 decades has buffers on its input/output jacks. That buffer protects the insides of the gear (as well as providing other facilities like balancing/de-balancing, impedance matching, etc.) from damage when connecting/disconnecting cables. Buffers themselves can be fried (which would mean that they've done their job protecting the rest of the circuit), but that's not all that common, and its a relatively easy fix. Not much to worry about IMO.

The only things I would watch out for are:
1. turn off the power switch before you plug/unplug a power cable, and
2. turn off phantom power before you plug/unplug a mic.

Well, it's usually a good idea to set a device's state to off before plugging in or pulling out it's main power supply.

It depends on what you're unplugging or plugging in, I think. For instance, things like USB (except storage devices) or MIDI cables are fine, while hot-plugging Firewire devices is not advised regardless of what some manufacturers say. You should be fine plugging your gear in before powering on in any case though. As for unique devices, you usually want to read what the manufacturer suggests, if applicable.

Some things you don't want to plug in while powered on are mics on external power supplies. Things you don't want to plug in nor pull out are I/O cables with a device's levels up or instrument cables that are routed directly to your monitors, while the monitors are on. I don't ever turn off anything when using patch cables or such, I just make sure I'm not routed to any of the monitors to avoid those potentially damaging (to monitors and ears) thunk noise or feedback. As far as mics, again, it's good practice to turn off phantom power before removing the cable and on after plugging in the cable...even if most mics won't be damaged...even if it's to avoid applying said power to mics that don't require it, as an extra precaution. You can unplug mics freely while your pre, interface or mixer is powered on. Though it likely won't happen, in rare occasions some pres or mics, notably obscure or older ones can be damaged but this has a lot to do with the connectors (for the same reasons as in the video) and other variables. In even rarer cases will a mic be damaged by phantom power due to it's kind. That's what I think anyway. Again, opinions may differ.
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It seems mp3 was slightly ahead by 2 mins or so. So, there you go.

i heard you can fry a ribbon mic with phantom power;
that's probably where the idea of turning it off as a habit came from. those **** aren't cheap !