Marshall JMP and Plexi Reissue question!!!!!!

Discussion in 'Amps and Cabs' started by mxr2000, May 19, 2008.

  1. mxr2000

    mxr2000 Member

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    Hi i would like to know if its possible to run a Marshall 1959 slp 100 watts reissue on 50watts with just taking the outer power tubes without experiencing any problems ???? and if the same can be done to a 1980 JMP 2203? anybody with some experience doing this?
     
  2. samtheman

    samtheman Member

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    Just reduce the speaker impedance by half when using two tubes ! i.e 16 -> 8 -> 4ohms

    Volume difference between 100/50 watter is only 3db, so its not help much.

    cheers

    /sam
     
  3. mxr2000

    mxr2000 Member

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    do i need to re do the Bias?
     
  4. IIIBOOMERIII

    IIIBOOMERIII Member

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    No to the rebias.

    You will notice that you hit the break up sweet spot without being as loud. Going from 100 to 50 doesn't do much for the over all volume, it can still get loud. But you will over drive the power section much quicker and get that warm power tube over drive without your ears bleeding....as much.

    There is a drawback to this, while cutting the wattage back from 100 to 50 lets you get into the OD section quicker. You will loose a lot of headroom which means your bottom end will start to disappear.

    Then there is always Yellowjackets. These are sockets that allow you to switch over to EL-84 tubes. So a set of 4 Yellowjackets will get you about 40 watts. And you will notice less bottom end.
     
  5. 1973Marshall

    1973Marshall Member

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    The funny thing is you will see a difference in feel and tone. More compression, a slightly "smaller" sound with more bite and less bass/girth. Very sweet all the same.

    You quickly realize there is a difference in tone between the models. Of course, the 100w model still has the large OT's in it. 50w Marshalls are quite a "sweet" tone indeed.
     

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