Power Map Ratings/ usage

Discussion in 'Amps and Cabs [BG]' started by Deman669, Sep 11, 2001.

  1. Okay, these are the specs of the Mackie 1400i:

    1400 watts @ 4 ohms bridged
    1000 watts @ 8 ohms bridged
    700 + 700 watts @ 2 ohms stereo
    500 + 500 watts @ 4 ohms stereo
    300 + 300 watts @ 8 ohms stereo

    Now, I have two new 8 ohm cabs on their way. I have a currently have a 200 watt amp, but I'll need more power. I'm considering amps, and how to run them. I could either:

    1) run my cabs in stereo, one per side of the amp (new or old) and get the RMS @ 8ohm power, which in this case is 300 watts per cab. or:

    2) I could bridge the amp, run both cabs parallel, making a four ohm load, and get the RMS Bridged @ four ohm (1400 watts).

    My question: why is there such a difference in the power bridged 4 ohm vs. stereo 4ohm? Shouldn't they just add? Stereo @4 ohm, and 4 ohm bridged is 400 watt difference. why?

    And now it is obvious that I'll just run my amp bridged, and my cabs in parallel. Unless there are advantages to running stereo? Headroom perhaps?
  2. Luis Fabara

    Luis Fabara

    Aug 13, 2000
    Ecuador (South America)
    Audio Pro - Ecuador
    Because each channel is actually sensing Half of the total load.
    In this Case, each chanell feels it as 2 Ohms.
    Thus producing 700 watts each so 1400 Watts total.
  3. Ahh. I see. now, then why would anyone run in stereo? perhaps if you actully need two independant channels I guess...
  4. Because most multi-fx boards / pedals have stereo-output ? stereo VS mono makes a lot of difference when doing stuff like flangers, etc..

    try doing a slide down the B-string while panning from left to right on a gig, that really rocks :)