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Question about hooking cabs up to a power amp?

Discussion in 'Amps and Cabs [BG]' started by xb100, Nov 29, 2004.

  1. xb100


    Mar 24, 2004
    NH, In
    Title says it all.

    How do you?

    I was reading the owners manual to a PV900 power amp, and i dont quite get of how to hooking up cabs.

    Maybe I'm making it to hard but could someone also explain to me how to bridge 8 and 4 ohms or something together?

    I'm going to get a qsc 1450 with either a tech 21 sansamp or a bmax pre amp and how do oyu hook those up to the power amp ax well.
    Thanks i appreciate it!!


  2. xb100


    Mar 24, 2004
    NH, In
    Btw since the rmx 1450 is 450 watts at 4 ohms per channel, does that mean if i hook 2 4ohm cabs to it in stereo mode that ill be pumping out 900 watts???

    ThankS again

  3. IvanMike

    IvanMike Player Characters fear me... Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    yes, if you hook up one 4 ohm cab to each side in stereo mode you will put 450 watts into each cab for a grand total of 900 watts
    plugging a preamp into a power amp is simple, plug the outputs of the preamp into the inputs of the power amp
    you don't bridge cabinets together, you bridge power amps. there are a few ways to hook up the cables once you hit the bridge mono switch on your power amp, so consult your manual. if your power amp can only safely power as low as 8 ohms in bridge mode, you can only use one 8 ohm cabinet in bridge mode. If it will safley power a 4 ohm load in bridge mono load you can power a 4 ohm cabinet or two 8 ohm cabinets, (which can be daisy chained together by running a speaker cable to one cabinet, and running a second speaker cable from the parallel input of the 1st cabinet to the input of the second cabinet
  4. xb100


    Mar 24, 2004
    NH, In
    Ok now that i have figured that out im a whole lot cleaer on how to hook stuff up now.

    But another question i have is if i how would i plug my pre amp in.
    Ivanmike you answered that question but im a little un clear about it.

    I was looking at the owner manual to the rmx 1450 and it has 2 speakon connections and 2 regular speaker cable inputs and thats it.

    What do you mean by plugging the output of the pre amp into the input of the powr amp?? Do you mean plugging it in with a DI thing-a-ma-jig? or something totally different.

    Thanks for all the info though

  5. Luigi


    Dec 3, 2003
    Just use a regular instrument cable (1/4") form the "line out" in your pre-amp to the 1/4" input in the power amp. By the way, the other set of inputs in that power amp are XLR's. The speakons are for the outputs ;)
  6. xb100


    Mar 24, 2004
    NH, In

    Well the qsc rmx 1450 has two 1/4 inputs and two speakon inputs.

    If i were to hook my pre into the channel one 1/4 input wont it just affect that channel one insted of both of the channels if i hook 2 cabs up in stereo?
  7. lo-freq

    lo-freq aka UFO

    Jan 19, 2003
    DFW, Texas
    The QSC amps have what is called a 'parallel' mode that takes one channel input and sends it to the two channels outputs (the levels of each channels' output can be controlled by the level controls on the front of the amp).
    You configure the mode of operation through dip switches on the back of the amp.

    Refer to the owner's manual.
  8. Luigi


    Dec 3, 2003
    Unless my RMX1450 is different, there are no Speakons for inputs. As far as input options, you can switch the RMX1450 to different configurations, one of them allows you to use one input while taking advantage of both channels in the power amp, sort of like using a Y cable.
  9. Eric Moesle

    Eric Moesle

    Sep 21, 2001
    Columbus OH
    Speakons are used ONLY for speaker line applications, NEVER for inputs. You won't find ANY amp manufacturer using speakons for line inputs!