Running 4 cabs???

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by lookslikemeband, Dec 26, 2004.

  1. lookslikemeband

    lookslikemeband Member

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    Hey gang -

    With my current rig, I run two amps (and A/B between them). I've got two Mesa 2X12's that I'd like to try to run on top of my Marshall 4X12's for a little extra "ummph".

    The Mesa's are wired for 8ohms, and my Marshalls can do 4/8/16.

    Can I run into the Marshalls on 4ohms, then parellel out to the Mesas??

    Any ideas??

    Thanks!

    Lance
     
  2. John Phillips

    John Phillips Member

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    Probably better to run the Marshalls at 16 ohms.

    You can't actually use them at 8 ohms unless you only want to run two speakers, which will defeat the point of wanting more 'ummph'.

    The sockets on the Marshalls aren't usable as in/outs - but the ones on the Mesas might be, I can't remember. So you need to go amp > Mesa > Marshall. Or, if the amps have two output sockets, simply run each to one of the cabs.

    Set the amps to 4 ohms if they have that option, or 8 if they don't. The true total impedance with a 16-ohm and an 8-ohm cab is 5.33 ohms, which is a safe mismatch from either 4 or 8 (if they're tube amps).

    2/3 of the power will go to the 8-ohm Mesa cabs.

    If you're absolutely sure the amp will take it, you could run the Marshalls at 4 ohms, then 2/3 of the power will go to them and 1/3 to the Mesas - it's still a safe mismatch from a 4-ohm output since it gives 2.66 ohms. You MUST set the amps to 4 ohms if you're going to do that. Don't try it with a solid-state amp.
     
  3. lookslikemeband

    lookslikemeband Member

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    Man... That is awesome! Thanks!

    For my current rig....

    I do have several outputs on my heads (they're Mesa/Boogie Dual Rectos. One is a Trem-O-Verb, for clean, and one is a Solo, for dirty). Do you know if it's safe to run cables out of the heads from different outputs??

    For example: Could I safely run a 4ohm output to the Marshall cabs AND an 8ohm out to the Mesa cabs??

    And yes, the Mesas are wired to be input/output jacks.

    Thanks again for all of your help!

    Lance
     
  4. John Phillips

    John Phillips Member

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    If they have two sockets and a selector (I think the T-Verb is like this, if I remember right?) it's safe to run two cables out of the amp. Set the amp to 4 ohms, whichever way you run the Marshall cab.

    If they're like the Solo and have two 4-ohm and one 8-ohm sockets, you can use the two 4-ohm sockets together, but NOT a 4 and the 8 at the same time... with one complicated exception:

    If you're with me so far ;) - you can run a 16-ohm cab from the 8-ohm socket and an 8-ohm cab from one 4-ohm socket at the same time. Since this is the combination you have, you may want to try it - you'll get slightly better power distribution between the two cabs.

    I think this may all be in the owner's manual for the amps... it is with mine (DC-5).
     
  5. lookslikemeband

    lookslikemeband Member

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    WOW! Thanks man!

    You guys here are AWESOME!!!

    I'm gonna try it.... If I blow up, it's been nice chattin!

    :D

    Lance
     

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