Here’s one of those recurring questions. Both of these examples came to us in the same day.
“Will it damage my dynamic mics (or the board) to have the phantom power on while leaving the dynamic and condenser microphones connected at the same time? My mixer manual says NEVER have the dynamic mikes plugged while phantom power is on, however, my Home Recording book says other wise, dynamic mikes are capable of handling phantom power without damage. Can you clear this up?”
“If I turn on the phantom power for a condenser mic, will the other things using the XLR ins (JV-1080, XP-10, GSP2101, etc) have their outs burned? Do I have to unplug everything else from the other XLR’s to use my mic?”
Okay boys and girls, today we’re going to take a field trip. First lets go to the Sweetwater Sound Home Page. On that page there is a place where you can perform searches (known as a search engine). Type in the word “phantom” and hit the Search button. You will find that “phantom” finds 114 pages on the Sweetwater Web site. However, if you look at the top three entries you will see that each of them is from a past TTOTD that is relevant to these questions. Then, the fifth entry is also a past TTOTD that is relevant. The sixth entry is the WFTD Phantom, which we defined some time ago. Most likely you will find sufficient information there to answer these questions.
If you ever want to specifically search on the TTOTD archives we have a page specifically for that you can get to from the inSync Home Page. Just click on TTOTD Archives to bring yourself to the TTOTD search engine. There is also a link to allow you to simply browse all of the TTOTD entries available at that page. Every tech tip and inSync we’ve ever done is archived on our Web site in these pages so don’t hesitate to use the search engines and archive listings to find answer to your questions. Who knows, maybe someone has asked your exact question before.
For those seeking the quick answer, phantom power can be left active for virtually all dynamic microphones. The word “virtually” is used only because there probably is some obscure microphone somewhere that can’t deal with phantom for some reason. If you’re using dynamic mics made in the last 30 years you should be fine. With ribbon mics you need to be a bit more careful, but again, anything made in the last 30 years should be fine. Either way, the risk is not to the mixer, only the gear you would plug into it. The main things you need to watch out for are devices with line outputs, like the direct out of a bass amp or keyboard. The GSP2101 and synthesizers mentioned above are a good example of things that could be fried by coming into contact with phantom power. Since the phantom voltage is applied across pins two and three of an XLR connector it is virtually impossible to have it be an issue for any unit with a transformer on its output. Therefore a great way to connect line outputs to XLR microphone inputs is with a direct box. Besides it is really not appropriate to connect line level outputs directly to the mic inputs on mixers anyway. A direct box (also known as a “DI”) lowers the impedance to make the signal more fitting for the mic preamp to deal with. If you want to make a direct connection (no direct box) just use the line input on the mixer.