Proper Method to Connect Separate 8 and 16 Ohm cabinets to a Marshall?

Discussion in 'Marshall Amps' started by Sacalait, Aug 22, 2019.

  1. Sacalait

    Sacalait Active Member

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    I did a quick Google but didn't really find anything. Both my JVM205 and SV20 have three "sets" of speaker jacks- 1-16 ohm, 2- 16 ohm (8 ohm load), and 2- 8 ohm (4 ohm load) speaker outs. I get that I plug two 16 ohm cabs into the 2- 16 ohm outputs to have a safe 8 ohm load on the amp. But what's the proper method of plugging an 8 ohm and a 16 ohm cab?
     
  2. Sacalait

    Sacalait Active Member

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    I'm guessing one cab into one of the two 16 Ohm sets and one cab into one of the two 8 ohm sets. But I don't wanna guess!!
     
  3. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    Do you mean connecting both a 16 ohm and a 8 ohm cabinet at the same time?

    If so, the 16 ohm cabinet gets plugged into an 8 ohm output jack and the 8 ohm cabinet gets plugged into a 4 ohm output jack.
     
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  4. ampmadscientist

    ampmadscientist Well-Known Member

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    Start the reactor. free Mars!
    If you use 16 ohm + 8 ohm, the total is 5.3 ohms.
    The amp must be set 4 ohm out to run that load.

    Speakers formula

    Speaker 1 X speaker 2
    -------------------------- = total load
    Speaker 1 + speaker 2
     
  5. Micky

    Micky Well-Known Member VIP Member

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    Not with a JVM...
     
  6. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    did not catch on to this yet
    short attention span
    :shrug: :D


    Or with an SV20 as well. :yesway:
     
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  7. Jethro Rocker

    Jethro Rocker Well-Known Member

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    Any amp with multiple outputs including SJ Reissues can be used in this way. Amps with an impedance switch cannot.
     
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  8. Sacalait

    Sacalait Active Member

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    All agree?
     
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  9. Jethro Rocker

    Jethro Rocker Well-Known Member

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    Yes. We don't all have to ahree, really. It's a fact.
     
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  10. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    Well you know I make shit up and I also state that I do not know anything. :D
     
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  11. LPMarshall hack

    LPMarshall hack Well-Known Member

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    Wait, so on those modern Marshalls with all those cabinet configuration jacks, you can use speakers of different ohms?

    I always thought that was a no no.

    Good to know I can plug my 16ohm 4x12 and my 8ohm 2x12 cabs into my JMD. Is this right?

    Edit: looks like the JMD does nit have a 4ohm out.:mad:
     
  12. JohnH

    JohnH Well-Known Member

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    its cool, and was confirmed for us years ago by Santiago (JVM desgner) on this forum

    Each speaker goes to an amp tap of half its ohm rating, and hence each provides half the load that the amp needs, and each gets half the power. All perfectly good and logical.

    Its not put in the manuals though, too hard to reliably explain to the average Joe Rocker.
     
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  13. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    You can always use a 32 ohm cabinet and a 16 ohm cabinet with your JMD:1. :D
     

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