Upgrade JVM410H with Mercury Magnetics OT and choke (pics)

Discussion in 'Amps and Cabs' started by svdijk, Sep 9, 2008.

  1. svdijk

    svdijk Member

    Messages:
    7
    Joined:
    Dec 22, 2007
    Location:
    Netherlands
    I finaly upgraded my JVM with a Mercury Magnetics choke, the MC-10H, and a Mercury Magnetics output tranny, the MAR-JVM100-O!
    Here are the pics:

    [​IMG]
    There goes my warranty!!
    The choke goes instead of the R106 resistor.

    [​IMG]
    Here you can see the difference of the two tranny's.

    [​IMG]
    Almost ready!
    [​IMG]

    The tranny didn't fit exactly, had to change the hole's!
    [​IMG]
    Here are the wires from the choke.

    [​IMG]
    Up and runnin' again!!

    Good things:
    The amp is smoother now, and reacts much better!
    The mids are sweeeeeet!!!
    The amp sounds bigger, because of the bigger and tighter lowend.
    And the lowend-thump is unbelievable.
    More harmonics.

    Bad things:
    Tranny didn't fit in the original holes.
    Drilling for fitting the choke.
    It's heavier now!
    Warranty is gone.

    The JVM is a very service-friendly amp, so it wasn't that difficult to do the mod!
    The output tranny was 225,- euro's and the choke 24,- euro's.
    And for me it was really worth it!!!

    The reasons why I did the mod, was that I was looking for more lowend in the OD1 and OD2 channels, and a thighter bass-response in the crunch-channel.
    And the feedback of the amp was not very musical to my ears.
    All those things are solved now for more then 100%!!
    Even the OD2 channel is awesome now, and reminds me of a Mesa Mark 4, but with a tighter lowend!!

    I was very used to my good old JCM800 2210 (alsow with MM ot and choke!), and missed some things in my JVM, like the nice feedback, and very big sound, but now the JVM can sound like that amp, and do a lot more then the JCM800!!
    Don't get me wrong, I always liked the JVM from the beginning, just tweaking it, like I did 21 years ago, when I bought my first Marshall, the JCM800 2210, that I still own!!
     
  2. photios

    photios Member

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    Nov 28, 2005
    Location:
    Kansas City Metro Area
    post of the day!!! Someone get this man a fruit basket.

    Big iron means big tone, musical harmonics, articulation and a solid low end...MM is king in my book. Thanks for sharing. I'm a BIG fan of MM tranny's...they're expensive, but if you really want to squeeze that last 10% out of your tone, worth every penny...or quid...whatever.
     
  3. digital jams

    digital jams Member

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    Very nice work!!!!!!
     
  4. Norjef

    Norjef Member

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    Please tell us about your JJ KT77s
     
  5. grayeyes777

    grayeyes777 Active Member

    Messages:
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    Apr 20, 2008
    +1... i hear the 77's are way bigger on the bottom then the 34's in this amp.
     
  6. Pa'ani

    Pa'ani Supporting Member

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    Location:
    So. Cal
    Congratulations on your new Mercury Magnetics Tranny and choke.
    Great job on the install!
     
  7. Melodyman

    Melodyman Member

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    Wow that looks real clean, very nice :)
     
  8. Soothsayer

    Soothsayer (Paul) Supporting Member

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  9. donbarzini

    donbarzini Member

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    I would sure like to play that and see if it "feels" any better playing with the choke installed instead of the stock resistor. Also, the biggest problem I found with the JVM besides feeling solid state, it was just sounding nasty the louder I turned it up, unusual since a Marshall usually likes to be cranked to sound best. You just may need to try out the MM Power Transformer as well.
     
  10. svdijk

    svdijk Member

    Messages:
    7
    Joined:
    Dec 22, 2007
    Location:
    Netherlands
    Those two problems are gone!!
    When I crank the mastervolume the sound is getting bigger, in stead of the hard and stiff sound it had before.

    I think the JVM is a very good designed amp, and such a design deserves quality tranny's.
    Maybe someday I alsow will change the
    powertransformer, but for now I gonna enjoy it this way.
     

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