firebox preamp question

Discussion in 'Preamps / Channel Strips' started by wags, Jun 18, 2006.

  1. wags

    wags Guest

    Hello, I have a firebox with the 2 XLR/instrument inputs in the front. What I want to do is record acoustic guitar using a condenser mic and plug the guitar's onboard preamp in the other channel. The problem is I think the phantom power applies power to both mic inputs. Will this harm the onboard preamp on the guitar(it's the kind with a 9 volt battery) if the phantom power is on? As far as I know you can't apply the phantom power to just 1 input.

    Thanks for any input

  2. RemyRAD

    RemyRAD Member

    Sep 26, 2005
    Well, if in doubt, purchase an active direct box. That would plug into the XLR input and require phantom power. Plus with that kind of an input, you are virtually guaranteed not to load down a passive pickup should you ever use one again. When you're not using phantom powered microphones, you can then plug anything you want into the 1/4" inputs as you assumed without phantom power.

    And if I were you, if you were really worried about blowing out your active preamplifier on your acoustic guitar if it sees phantom power, I'd pick up the telephone and call the manufacturer. It's cheaper. Just tell them you need customer support. I used to do that all the time. It's fun and you learn something generally.

    Thinking inside the box
    Ms. Remy Ann David
  3. tallrd

    tallrd Active Member

    Jul 11, 2006
    Madison, WI
    Home Page:
    I would call them/email them directly on that one:
  4. Boswell

    Boswell Moderator Distinguished Member

    Apr 19, 2006
    Home Page:
    As long as you use the 1/4" jack inputs on the combo jack/XLR connectors for your guitar, you won't have a problem with either input impedance (1M Ohm) or phantom power. The phantom power is only present on the XLRs.

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