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GK700rb ohm question

Discussion in 'Amps and Cabs [BG]' started by etaym, Feb 2, 2006.


  1. etaym

    etaym

    Mar 28, 2005
    Newton, MA
    Hi. i own a GK 700rb amp and a 2x10 eden 4ohm cab. i would like to add an 8ohm 1x15 but i understand this would be a problem.

    someone told me i can connect the 2x10 to the amp and somehow connect the 1x15 to the 2x10. i would like to hear your opinion since i have no knowledge when it comes to electronics.

    from my basic basic basic understanding: the amp is 4ohms. i want to connect 4 an 8. the amp will not appreciate this :meh:
     
  2. Tony G

    Tony G

    Jan 20, 2006
    NY
    You are correct for the most part here. The lowest your amp will go before damaging itself and/or the speaker is 4 ohms. You're best bet if you wanted to use two cabs, is to have two 8 ohm cabs connected directly to the outputs of the amp (in parallel), it would result in a 4 ohm load. As I was corrected by tornadobass, "Whether you plug both cabs into the amp or daisy chain cabs, it's still parallel wiring and results in an impedance below 4 ohms". If you connect both cabs directly to the back of your amp (in parallel), it would result in a 2.66 ohm load, which is not good for your amp. Here is a couple of links to read that easily explain what you are going through:

    http://www.musiccenters.com/vol.html

    http://www.crutchfield.com/S-BwWmqE3YmpO/tech/kb334.html
     
  3. etaym

    etaym

    Mar 28, 2005
    Newton, MA
    thanks!! one question then - if i connect the 8ohm to the 4ohm you say the result will be 12ohm and will not take advantage of my amp. The what WILL happen? will i get a weaker output then just the 4ohm? will i lose lower/higher frequancies?
     
  4. tornadobass

    tornadobass Supporting Member

    Nov 20, 2000
    Iowa City, Iowa
    Endorsing Artist: Black Diamond & SuperSensitive strings
    Nope...this isn't correct. Whether you plug both cabs into the amp or daisy chain cabs, it's still parallel wiring and results in an impedance below 4 ohms.

    To get series wiring, you need to either get a special cable or make up an outboard box that accomplishes series wiring.

    But then you'd still have unequal power to the two cabs, with the 4 ohm drawing more.
     
  5. Tony G

    Tony G

    Jan 20, 2006
    NY

    Ok. Thanks for clearing that up. I wasn't completely sure about that.
     
  6. etaym

    etaym

    Mar 28, 2005
    Newton, MA
    now im really confused :(
     
  7. In the most simple terms....do not use a 4 ohm cabinet and an 8 ohm cabinet with this amp because it will fry...


    Even if was able to go to 2 ohms, it is still better to always use matching cabs (ohm wise) just so that each cab is drawing the same amount of power
     
  8. The only way this amp could power both cabs is to bi-amp. However, the 8 ohm cab would only receive 50 watts, not likely enough for a 1x15. Further, it'd be pointless to send the highs to a 1x15.

    You may want to check out (2) 8 ohm cabs.
     
  9. tornadobass

    tornadobass Supporting Member

    Nov 20, 2000
    Iowa City, Iowa
    Endorsing Artist: Black Diamond & SuperSensitive strings
    Keep in mind, too, that on the 700RB, only the real highs...clicks and finger noise go to the high freq amp. This is quite different than the 800RB, where you can split the frequencies to actually involve the woofer.

    The 700RB's high freq amp is only in the range of the tweeter.
     

  10. I didn't realize that. Would it be the same for the 1001rb, and2001rb models?
     
  11. tornadobass

    tornadobass Supporting Member

    Nov 20, 2000
    Iowa City, Iowa
    Endorsing Artist: Black Diamond & SuperSensitive strings
    Yes...same thing...for the 1001RB. If you look at the PDF manual, you'll see that the woofers can run either full range or be trimmed at 5Khz (IIRC) and the tweeter can be capped at, I think, 10Khz.

    But the crossover frequency is fixed. From the GK manual:

     
  12. Thanks for the info. I have been looking at the 800rb, now it's even more interesting.