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yamaha trb jp problem

Discussion in 'Hardware, Setup & Repair [BG]' started by southernconfort, Jan 7, 2012.

  1. southernconfort


    Feb 11, 2011
    croatian bass player

    i have strange problem adjusting dual truss rod on my yamaha trb jp
    bought 6 month ago and first day make change from roundwound to flatwound rotosound
    before on my old bass when i replace round to flat string, need just a 1/4 turn on each truss rod and everything was fine
    but on trb jp after 8 whole tour was enough to get right relief
    so i release all 2 truss road to a minimum and make quarter turn every half hour and make relief good but not perfect
    problem is next:

    If i setup both truss rod on 4 full laps, on bass side i have a good relief, but on the treble side is too much
    If I reduce for 2 full rounds treble side off relief is not perfect good, but the c string is too close to the first fret?
    After I lifted string on bridge about 1 inch seems ok but it is simply too much for normal play
    I tried to lower treble truss rod until I came to a minimum but still not enough
    when i press 24 fret on c string, string also touching first fret
    c string is too close to 1 fret ***?
    2 truss rod : one is on 4 rounds and 2. is on 0 and still not enough
    with this setup relief is almost good???
    it is simply impossible to make a harmonic slide because when i make little pressure on c string like when you play harmonic, string is touching the 1 fret
    the G string is in little better situation and the other looks all ok


    If the dual truss road are parallel its setup a equally
    If they are in v position, treble side setup a normal and bass side just a little to assist him
    in my case is not good neither

    what to do???
  2. I feel your pain. I hate it when "repair techs" fool around with my truss rods. Yamaha did a great job selecting the wood for the neck. I have had it since it was new and of all my basses, my JP has only needed adjusting twice. Having said that, "you gotta do, what you have to do." This is a trick I learned from a great tech and player Danny Joe Carter. As you slowly make you adjustments, equally on each side; i.e., both truss rods at the same time. Turn the bass over, lay it in your lap with the neck supported. Gently, very gently push down on the back of the neck as you hold the neck with your left hand. You will feel the neck flex just a little, one push no more than two. turn the bass over and tighten the truss rods a little. It is important that you measure with a ruler at first and then a feeler gage. Try to get .015. When measuring be sure that the first fret has a capo at the first fret. hold the string with one finger where the neck joins the body. Slip the feeler gage at the seventh fret for the .015 or .381mm.
    I don't know what is going on with your bass, but the reason why you gently push or flex the back of the neck is to help loosen the truss rod. Could be a little glue or just tight. However, if you push the neck too hard it will break!!!!!!! If you over tighten the Truss rods they can also break or do great damage. Its like a chiropractor cracking a back. Tune the bass up and leave it alone then come back to it later.

    Finally, the techs at yamaha are awesome. You will find them to be a wealth of knowledge. Oh, one other thing. These basses need a little relief for the B string to sound deep a punchy. When you talk to the people at yamaha ask what the spacing should be at the first fret! If it is too low you will never get a good setup.

    This is how I do it, it works for me. Best of luck to you!

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