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stupid power amp question...

Discussion in 'Amps and Cabs [BG]' started by khedspeth, Mar 21, 2009.


  1. Looking at a power amp that has the following ratings...

    200W/channel @8 ohms
    830W @ 4 ohm bridged

    If I have 8 ohm speakers, couldn't I just run the amp in bridged mode into my two 8 ohm cabs in parrell to get 415W/cabinet? Am I missing something?

    Thanks for the enlightenment.
     
  2. If the amp has the ratings you specify you would be safe to do as you suggest. The amp should also have a rating of 415W/channel into 2Ω.

    Paul
     
  3. Paul,

    Thanks for the confirmation and you are correct on the 2 ohm rating.

    Kevin
     
  4. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    If you run your amp in bridged mono (830 watts @ 4 ohm) and daisy chain your two 8 ohm speaker cabs together, you'll be seeing a 4 ohm total speaker load and the full 830 watts from the power amp.

    Riis
     
  5. ok, sounds like i'm good to go. Here is the question that now comes up. The amp (QSC RMX850) is spec'd at 830W bridged into 4 ohms. However, on the back of the amp is says minimum load for bridged mono is 8 ohm. If I run inputs into both channels (stereo) but run the output bridged, will I be ok with a 4 ohm load?
     
  6. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    Hold on until we take a look at the manual.

    Riis
     
  7. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    Here's the manual. Print and read before continuing.

    http://media.qscaudio.com/pdfs/manuals/RMX_User_Manual.pdf

    In bridged mono, you use only one input and one output (channel 1 Speakon or the two center binding posts). Can't find a reference on the min. 8 ohm bit but I just skimmed the text. You might want to ask Bob Lee here on TB for a quick, informative, and friendly answer.

    BTW, this was not a stupid question. I'm using the RMX 1450 in bridged mono to drive two small subwoofer cabs (8 ohm each).

    Riis
     
  8. Riis,

    Thanks for spending time on this and helping. I did read the manual and it clears things up alot. Love the support on TB.

    Thanks,

    Kevin
     
  9. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    The RMX850 is okay bridged into a 4Ω load, as long as you are careful to avoid clipping, keep the cooling air flow unobstructed, etc.
     
  10. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    Thanks, Bob!

    I'll take it one step further: the RMX850 will work but I would opt for something with a little more oooomph, given the stated application. I just snagged a PLX 3102 and have been more than satisfied.

    Riis
     

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