Cabinet and speaker OHM question.

Discussion in 'Amps and Cabs' started by mims2, Aug 25, 2008.

  1. mims2

    mims2 Member

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    I just bought a Lopoline 2x12 diagonal cabinet. I play through a Mesa F-50 head and I have 2 8 ohm Vintage 30's and 2 8 ohm Celestion T75's. Are these speaker together the right ohm for my amp, and if so what speaker output of the amp do I plug it in, 4,8 or 16? Thanks a lot!
     
  2. rockon1

    rockon1 Member

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    If you wire them in series-16 ohms
    If you wire them in parallel-4 ohms. Bob
     
  3. mims2

    mims2 Member

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    How do I tell the difference? I am just using the two jacks for each speaker that came with the cab. Boy I prolly shoulda learned this stuff a long time ago. Can anyone tell me whick output to plug it in on the amp though?
     
  4. fizbin

    fizbin Member

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    How many wires are going between the two speakers themselves inside the one cab? (not to the jacks)

    0 wires between speakers - this means all 4 wires go to the jack, which means parallel, which means 4 ohms.
    1 wire between speakers - this means they are in series, one wire from jack hot to speaker A, one wire between speaker A and B, one wire back to jack ground. 16 ohms
    2 wires between speakers - This means 2 wires from jack to speaker A, 2 wires from speaker A to speaker B, which means parallel. 4 ohms
     
  5. salvatruco

    salvatruco Member

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    here is a link to wiring parallel or series http://www.avatarspeakers.com/wiring diagrams.htm


    If your cab is already set up and you need to now the ohms, you'll need a multimeter that has OHM reading or if you can see the wiring inside the cab and compare it to the above link , you'll be able to know excatly the ohms out of your cab. now, by knowing the cab ohms the only thing you need to do is to choose the right ohms on your amp( I am guessing that your amp has a switch to choose the right ohms). good luck
     
  6. mims2

    mims2 Member

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    none between the 2 speakers. Just two cables from the jack. Both speakers are wired up independently to the jack.
     
  7. fizbin

    fizbin Member

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    Parallel - 4 ohms

    Note that this also means you cannot run another cab off of your head with this 4 ohm cab or it will take the impedance down too low.
     
  8. rockon1

    rockon1 Member

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    If the cab came pre wired its probably in parallel. Do both sets of speaker wires go to the jacks? Do you have a multimeter? You can measure the resistance at the tip and sleeve of the cable. It should be around 3 ohms if its parallel and 14 or so if its series. Whatever you do make sure youve got a handle on it before playing thru it.

    Maybe this will help

    Parallel= 4 ohms with 2- 8 ohms speakers

    [​IMG]

    Series=16 ohms with 2-8 ohm speakers

    [​IMG]
     

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