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Can phantom power fry equipment?

Discussion in 'Recording' started by MAXIMILIAN, Apr 11, 2005.

  1. MAXIMILIAN

    MAXIMILIAN Active Member

    If I were to use a condenser mic and send it to a compressor (xlr i/o) before going into a motu 896 hd with phantom power enabled on the mic input, would I damage the compressor? I was going to use an outboard phantom power adaptor or go directly from the mic to the motu and use a send/return loop for the compressor just to be on the safe side, but I thought I'd ask.
    What pin (on xlr) does phantom power run on?
     
  2. jonyoung

    jonyoung Well-Known Member

    You have to send the mic to the preamp stage of the motu. There isn't enough signal from the mic for the compressor to do anything with. And yes, you'd probably fry the compressor by sending it phantom power. Use the insert scenario instead.
     
  3. MAXIMILIAN

    MAXIMILIAN Active Member

    thanks.
     
  4. jonyoung

    jonyoung Well-Known Member

    You're welcome. BTW, always power up your phantom before connecting a mic to it, and disconnect mic before powering phantom off. Possible voltage spikes can fry a mic.
     
  5. maintiger

    maintiger Well-Known Member

    and you can fry a ribbon real easy if you turn on the phantom power...
     
  6. vaibhs

    vaibhs Guest

    XLR has three pins Left Right and External?? i guess
    am not sure wht the X stands for
    i had read it somewhere but am not sure if its External....i guess am wrong
    anyways phantom power flows through both Left and Right wire

    as it it Balanced connection it is cancelled at the input of the Mixer
    and only the audio signal enters the Mixer

    guys do reply me wht X stands for..
    $*^t man this is basic how can i forget it
    pls help me out with this stupid thing man
     
  7. mikezfx

    mikezfx Guest

    X stands for ground (it is connected to the cable shield).

    Pin 1 (X) = ground
    Pin 2 (L) = + most commonly, or Left
    Pin 3 (R) = - most commonly, or Right
     
  8. EroticPoetry

    EroticPoetry Guest

    If I use mic-preamp(with phantom power)-compressor-multitracker...it wouldnt do anything to the compressor right?

    I need a fairly quick answer, as I'm set to record tomorrow.
     
  9. ghellquist

    ghellquist Member

    Quite few wrong answers.

    XLR is a product series that started out as the X series. Check this place
    http://www.nullmodem.com/Audio.htm

    Has nothing to do with Left or Right.

    There are three pins. Phantom power is connected to both pin 2 and pin 3 (but as long as your cable is not broken, simply use it).

    It will NOT fry ribbon mics as long as it is not broken (unless your ribbon is a vintage model). A broken cable can fry a ribbon mic. A mic made for T - power (came before phantom power), connected to phantom power will most probably be damaged. And so on. But phantom has been a standard for more than 30 years.

    And the phantom power is only on the Mic input side of a preamp. Not on the line output, so just connect your compresser or whatever there.

    Gunnar
     
  10. ErichS

    ErichS Active Member

    I'v always heard the oppisite of this. Wouldn' t having the phantom power on before you plugin a condensor mic cause damage?
     
  11. Reggie

    Reggie Well-Known Member


    Yeah, me too. :?
     
  12. karbomusic

    karbomusic Active Member

    Dont do it with PP on....

    I think you just worded this backwards, the spike comes from pulling the cable while phantom power is on. I would not try this. One of the issues when unplugging the mic with Phantom Power on is the sudden disconnection of the power when the mic is unplugged. The loud pop you hear is the circuit spiking suddenly for lack of a better term. I don't remember my electronic physics enough to use the correct terminology but it is the equivilant of jerking an ac cord of a vacuum cleaner out of a wall while running. You see a big spark which is the circuit trying to jump over and complete... I remember a theortical scenario that states (using the vacuum cleaner example) that if you could unplug fast enough to get the plug 100 miles away from the wall instantly (no time elapsed) that the spark would jump 100 miles to catch it. The point is that jerking a microphone cable out of a mic with Phantom Power on is risky and dangerous. In my early learning years, I remember a few engineers who totally freaked when I did that!

    As far as your monitors go, turn down all master levels before unplugging OR powering down to protect your speakers also...

    So the steps when connecting are:

    1. Turn down those master faders.
    2. Plug in mic.
    3. Turn Phantom Power on.

    and when disconnecting:

    1. Turn down those master faders.
    2. Turn Phantom Power off.
    3. Unplug mic.

    Karbo
     
  13. Hitman

    Hitman Guest

    What about phantom power and dynamic mic's. Will phantom power damage dynamic microphones? Or is it cool to plug a dynamic into a channel that has phantom power on?
     
  14. ErichS

    ErichS Active Member

    Re: Dont do it with PP on....

    Karbo,

    Will it hurt either the preamp or condensor mic if you plug and unplug the mic with the preamp on, but the phantom power off?

    Thanks
    Erich
     
  15. karbomusic

    karbomusic Active Member

    Hi Erich-

    Ive been out of the audio biz for a few years so please excuse me if I mis-state anything... However, as to your question above, I don't think so. The biggest issue with Phantom Power is the 48volts suddenly being disconnected. Connecting a mic to a mic-pre there is no real voltage other than the mic signal which is miniscule compared to 24/48volts of Phantom power. I can say I have never had an issue with mic pre's just pp..

    Best regards-

    Karbo
     
  16. karbomusic

    karbomusic Active Member

    The risk is higher if it is an unbalanced connection. The Sound Reinforcement Handbook by Yamaha says something like this:

    "In a phantom power system, the polorizing supply volatage is placed on both of the signal lines in a balanced connection, with the same polarity on each line. Dynamic microphones connected in a balanced system with a phantom power input are then protected from damage, theoretically, since the system results in a net zero DC potential across the coil. However, a dynamic mic connected unbalanced to a phantom power input may be destroyed."

    In other words if you take a sm57 and plug it into a phantom powerd mic pre using a normal balanced mic cable then you should be safe.

    If you take an unbalanced mic and wire it with a xlr plug so you can connect it to that same input then you could fry the mic. In a balanced connection the 48 volts is runnng parallel down the 2 signal wires. With an unbalanced connection (2 conductors) you have 1 signal wire and ground and doing this is basically completing a circuit that sends 48volts directly to the mics voice coil.

    Can't say I have ever connected an unbalanced mic to a phantom powered mic pre since... if i were to be using an unbalanced hiZ mic I would probably hit a balanced DI first anyway. Or be plugging in to some type of hiZ input that did not have phantom power fed to it to begin with...

    Hope this helps!

    Karbo
     
  17. ErichS

    ErichS Active Member

    Karbo

    Thnaks very much for those replies.

    Erich
     

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