Question about disabling distortion in a Roland JC amp

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Neer, Jan 1, 2018.


  1. Neer

    Neer Member

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    ok, yes, I love using a JC-45 amp for my steel guitar on gigs. The clean sound works for me and my multi-effects unit sounds great with it. I’d prefer to use my 100 watt Twin with JBLs, but let’s be real.

    The problem is, no matter what I do, I always seem to end up with distortion knob creep—even the slightest movement of the knob destroys my sound.

    How can I completely disable that circuit or bypass that pot to eliminate this issue? Is there something I can do with the footswitch jack to keep the distortion off permanently? The only solution I've been able to come up with is to leave a footswitch connected in the back of the amp in the 'off' position--I'd prefer something more permanent and less reliant on an external gadget.

    Thanks.
     
    Last edited: Jan 1, 2018
  2. Jeff Gehring

    Jeff Gehring Silver Supporting Member

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    I can find no example of a Roland JC-45 schematic to look at. The gist of what you need to do is to:
    • determine what type of connnector is used to plug into the footswitch jack (that controls the distortion), and buy one, and
    • determine what the real footswitch does to disable the distortion, and
    • wire up your plug that you bought to provide a permanent 'no distortion, please' connection to the amp's footswitch jack electronics.
    It shouldn't be very hard, unless the plug is a weird/unobtanium style. In the 80's JC120's, all the footswitch does to disable the distortion is to provide a connection between ground and another point, both of which are available at the footswitch jack connections.

    If you can link a JC45 schematic, you will get more specific help, I'm sure...
     
  3. Neer

    Neer Member

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    Thanks, man. Yeah, it's a JC-40, sorry. I kind of figured there would be a simple solution. Without going inside and seeing the jack situation--I'm guessing probably a circuit board and a nylon jack--an external fix might be the only option to bypass at this point. I'm currently using an old, simple one button footswitch.
     
  4. Jeff Gehring

    Jeff Gehring Silver Supporting Member

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    So, it looks like all you need to do to disable the distortion is get a right angle 1/4" plug, solder it so it is tip to sleeve shorted, plug it into the distortion FS jack on the back and party on.
     
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