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Marshall JVM and Midi Controller

  • 27-10-2007 2:49pm
    #1
    darrenw5094
    Closed Accounts Posts: 2,126 ✭✭✭


    I have just purchased a Marshall JVM 100w combo.
    It comes with a foot controller with 6 switches on it. 4 for the 4 channels, one for switching between the 2 master volumes and one for switching on and off the FX loop.

    Each of the 4 channels ( Clean, Cruch ,OD1 and OD2) has 3 modes, where the overdrive is slightly greater every time you click on the footswitch.

    When i go into mode 2 and 3 in each of the 2 OD channels, i am getting alot of feedback when i pause between notes.

    It also has midi capability. The midi input is in the back.
    I am wondering if i could lose the foot controller and use a floor midi controller to store and use some custom tones and sounds from the amp.

    Is this possible, and if so, how do i do this?

    Has anyone got any feedback problems from the new Marshall JVM series?

    Hanx :rolleyes:


Comments

  • #2
    feylya
    Moderators, Music Moderators Posts: 23,363 Mod ✭✭✭✭feylya


    Stupid question but did you check the manual? You will not be able to store patches via midi for the amp more than likely. The midi will only be used for channel changing.


  • #3
    Voodu Child
    Closed Accounts Posts: 6,706 ✭✭✭Voodu Child


    I bought an amp off a guy recently who was saying he had feedback problems with the JVM, and heard of others.

    Tbh, as with 90% of valve amp issues, it's probably a valve related problem (preamp valves in this case). Marshall have just been using a lousy supplier.

    Have a look at the preamp valves, standard checks (replacing one at a time etc). I'd wager that'll clear it up.

    The bias of some brand new JVMs has found to be way off too, might as well check that if you know how. It's not related to this problem, but it's worth having the bias set right anyway.


  • #4
    darrenw5094
    Closed Accounts Posts: 2,126 ✭✭✭darrenw5094


    feylya wrote: »
    Stupid question but did you check the manual? You will not be able to store patches via midi for the amp more than likely. The midi will only be used for channel changing.

    I am a numpty. There is a foot controller/midi button on the front panel.
    Which means i can store patches from the JVM on the foots controller that comes with it.

    You are the boards.ie king Feylya.....imagine not reading the fricken manual. Huh.

    :):):):):):)


  • #5
    darrenw5094
    Closed Accounts Posts: 2,126 ✭✭✭darrenw5094


    voodoo_child wrote: »
    I bought an amp off a guy recently who was saying he had feedback problems with the JVM, and heard of others.

    Tbh, as with 90% of valve amp issues, it's probably a valve related problem (preamp valves in this case). Marshall have just been using a lousy supplier.

    Have a look at the preamp valves, standard checks (replacing one at a time etc). I'd wager that'll clear it up.

    The bias of some brand new JVMs has found to be way off too, might as well check that if you know how. It's not related to this problem, but it's worth having the bias set right anyway.

    Bloody unbelievable that in this day and age we get these problems from a new Marshall or any new amp.

    Also when i switch from one channel to the next, there is a slight pause for about half a second. It is very noticable in the middle of a song or even going in or out of a solo.

    I don't even know what bias is either.

    Flip. Flip. Flip.


  • #6
    Voodu Child
    Closed Accounts Posts: 6,706 ✭✭✭Voodu Child


    darrenw5094 wrote: »
    Bloody unbelievable that in this day and age we get these problems from a new Marshall or any new amp.

    Also when i switch from one channel to the next, there is a slight pause for about half a second. It is very noticable in the middle of a song or even going in or out of a solo.

    I don't even know what bias is either.

    Flip. Flip. Flip.
    Ah, it's not a problem, just a bad (microphonic) preamp valve hopefully. It happens.

    The pause when channel switching is just the nature of the switching method used. Some amps make loud pops, some go silent when channel switching, some take ages, others are perfect. There's lots of ways of approaching the channel switching circuit, I guess the JVM just uses a method that's a little slower than you'd like. Again, not a problem with the amp, nothing to worry about or take it back over. Just the way she goes.

    Biasing isnt really important for now, i just thought i'd mention it in case you knew how. Most amps should be biased perfect out the factory and you don't even need to think about it until the first re-valve, but like I say, i've heard reports of a few guys who put a multi-meter on their JVMs and found they were running cold.


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  • #7
    darrenw5094
    Closed Accounts Posts: 2,126 ✭✭✭darrenw5094


    I have just noticed that i do NOT get the feedback problem when i use my Ibanez Jem with the Marshall.

    My Gibson had a pickup change about 6 months ago and sometimes gives off a buzz noise. The buzz goes away when i tap one of the volume pots....very strange. I only get the feedback problem with the Gibson Les Paul.


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