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yamaha bbt500h plus 3 cabs help

Discussion in 'Amps and Cabs [BG]' started by bryanonbass, Aug 15, 2007.


  1. bryanonbass

    bryanonbass Supporting Member

    May 13, 2001
    Northern NJ
    so i just want to figure out the best way to run 3 cabs from this yamaha head which only has 2 speaker outs.

    I have the yamaha bbt500h running into 2x bagend 15's (both 8 ohms) and a yamaha bbt110s 1x10 cab (which is 4 ohms)
    so I am running the minimum 2 ohm load correct?

    should I run the one speaker out into a bagend and then another cable from the bagend to the other bagend and run the yamaha 1x10 speaker off the 2nd speaker output of the amp?
     
  2. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    When you connect speakers together via the connectors on the cab, that's a parallel connection. Funnily enough, the two speaker out connections on the amp have the same effect, a parallel connection. So it doesn't really matter how you connect the 3 cabs, you'll always end up with a 2 ohm load.

    The only way you wouldn't end up with 2 ohms is if one of the connections is serial instead of parallel. Given that serial connections require special cables to be made up, I can almost guarantee you this won't be a concern.

    If you want to double check, connect the speakers together in any combination you like, then check the resistance with a multimeter. On a 2 ohm load, you should get a reading on approximately 1.3 ohms or thereabouts.

    The bigger concern with this setup is the power distribution, which is of course governed by the speaker impedances. From memory that amp puts out 500W? At full power, the 1x10 will draw 250W on its own, and the 15's will pull 125w each. It still might sound OK, just be aware of it in case you push that 1x10 too hard.
     
  3. eots

    eots

    Dec 18, 2004
    Morris, IL.
    I agree with Petebass (except the 1.3 ohm part. It should read 2 ohms, no?)
    Ideally, you'd want a 4 ohm 15" cab paired w/ either a 4 ohm 2x10 or a pair of 10" 8 ohms cabs.
    It won't matter if you daisy chain all three speakers from one jack on the back of the amp or any combination there of as far as the amp is concerned, it'll see 2 ohms. Same output, but in your case the single 4 ohm cab will be using 2x the power as either of the other 8 ohm cabs.
    No harm done to the amp so let your ears decide if you like it.
    The placement height and direction of the cabs may determine what you hear also. Might try pointing the single 10" at an upward angle.
     
  4. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    Try it, I bet you I'm right.

    What you're actually measuring with the multimeter is DC resistance. The amplifier doesn't see DC resistance, it sees AC impedance. They're not the same thing, though they are both measured in Ohms which is why it's easy to confuse them.
     

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