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How do I hook up my preamp to my poweramp running two cabs in stereo, 1 per channel?

Discussion in 'Amps and Cabs [BG]' started by ::::BASSIST::::, Jun 10, 2005.


  1. ::::BASSIST::::

    ::::BASSIST:::: Progress Not Perfection.

    Sep 2, 2004
    Vancouver, BC Canada
    [​IMG]

    If i want to run two cabs in stereo, one per channel, how do i plug in my preamp (Fishman pro platinum)?

    I will be using a stewart Pro Reference 1000, which is pictured above. Do I have to run a "Y" cable from my xlr output which would go to each input on the stewart?

    This will be my first attempt at hooking up such a setup.

    :)
     
  2. That's how I did it with my BBE BMax.
    "Y" cable from pre amp out, to power amp inputs.
    Then just hook up your speakers, and you're in business.
     
  3. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    yes. a y cable is the ticket. in my case i was only able to find a planet waves 1 male to 2 female y cord. i had to get two very short male to male patch cords to run the output of my single output preamp into the inputs of my stereo poweramp.
     
  4. ::::BASSIST::::

    ::::BASSIST:::: Progress Not Perfection.

    Sep 2, 2004
    Vancouver, BC Canada
    so if i wanted to run to one channel and have a di for the sound man I could use one of the sides of the Y for the poweramp and the other to the board (perhaps using an adapater)?

    While using the Fishman is there another way i can have one output for the soundman and one for my poweramp? it does have a 1/4 output as well, but I assume the output signal is from the 1/4 is not hot enough.

    when i use a Y cord is the output signal reduced?
     
  5. zombywoof5050

    zombywoof5050

    Dec 20, 2001
    If you use a y-cord, don't you only get half the signal strength to each line?
     
  6. Masher88

    Masher88 Believe in absurdities and you commit atrocities

    May 7, 2005
    Cleveland, OH
    Are you trying to run 2 effects through the 2 separate cabs? Like, distortion on one side and chorus through the other? If not, then can you bridge the amp and run the 2 cabs in parrallel? Your amp can get 430 watts bridged to a 4 ohm load. You'll be much louder than running a "dual mono" setup. What are the ohm ratings on your cabs? Your bass is a mono instrument to begin with, so there is really no benifit to getting a y adapter and running stereo unless you are having fun with stereo effects like delays and flanges and choruses.
     
  7. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    with a short y cord you'll get very little signal loss. (and no, using a y cord doesnt mean each side automaticaly gets 1/2 the original signal level)

    to run a signal to the board you'll need a DI box (if the fishman doesn't have a DI out). The signal from the output of the preamp isn't appropriate for this. The output of most preamps is a high inmpedance line level unbalanced signal intended to be run into a poweramp input.

    A DI signal intended to be run to a board is a low impedance balanced low/mic level signal (sometimes hotter, but not as strong as a line level signal in most cases). Even if a board is able to take the hotter line level signal running a long cord with an unbalanced high impedance signal will result in signal loss, signal degredation, and noise.
     
  8. ::::BASSIST::::

    ::::BASSIST:::: Progress Not Perfection.

    Sep 2, 2004
    Vancouver, BC Canada
    Thanks guys.

    It looks like I will have to get a sabddi, I was debating it, but if I need a di... might as well.

    Masher88 This is a stewart Pro Reference 1000. The reason i want to run two cabs, one per channel is b/c this will give me the most watts from the power amp.

    here are the specs:

    FTC Power Rating
    <0.1% THD
    20Hz-20kHz
    both channels driven 200W x 2 @ 8 Ohms
    350W x 2 @ 4 Ohms
    FTC Power Rating
    bridged mono 400W x 1 @ 16 Ohms
    725W x 1 @ 8 Ohms

    Since i have one 4 ohm cab ( and will be getting another one eventually) I will have to run one per channel>>> 350w x2 @ 4ohms= 700w.
     
  9. ::::BASSIST::::

    ::::BASSIST:::: Progress Not Perfection.

    Sep 2, 2004
    Vancouver, BC Canada
    Thanks Smash.

    Worse case scenario he could just mic the cab right?
     
  10. Bob Lee (QSC)

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

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    No, a Y cable will put the same signal voltage from the preamp output into both inputs. That's the way to do it unless the amp has a switch or switches for connecting the inputs in parallel.
     
  11. mrpackerguy

    mrpackerguy Supporting Member

    Jul 3, 2004
    Madison, Wisconsin
    So on an RMX850 if I'm running my two Acme 2x10 cabs in parallel, will the RMX850 send 300W to each cab?
     
  12. Bob Lee (QSC)

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

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    RMX 850 power:

    200W/ch into 8 ohms (EIA)
    300W/ch into 4 ohms (EIA)
    430W/ch into 2 ohms (EIA)

    I can't answer your question with more specificity because I don't know the impedance of your cabinets. If they're 4 ohms each and you connect one to each amp channel (not connected in parallel), then the RMX 850 will be able to put out up to 300 watts to each one. I hope that helps.
     
  13. mrpackerguy

    mrpackerguy Supporting Member

    Jul 3, 2004
    Madison, Wisconsin
    Yea, I could've explained it better. I'm running two 4ohm cabs in the QSC's parallel mode with one input into the amp. My question then is: am I getting 300W into each cab running them in parallel?
     
  14. Bob Lee (QSC)

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

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    The RMX 850 is rated at 300 watts per channel into 4 ohms.