Epiphone 339 intonation woes

Discussion in 'Luthier's Corner' started by Telzilla, Sep 23, 2017.

  1. Telzilla

    Telzilla Junior Member

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    I have an Epi ES 339 I got maybe 4 years ago, and the intonation has never been quite right on the G string.

    The original bridge is 11.4 mm by my electronic caliper. As you can see with the pic below, I had the G saddle all the way back and flipped it around, and the 12 fret was still a tiny bit sharp.
    [​IMG]

    So I got a new, wider bridge (14.2mm by my measure). Problem solved, right? Well, you can't turn these saddles around, so I'm still in the same spot- G stringsaddle all the way back, 12 fret still a tiny bit sharp. See below:
    [​IMG]

    Also, and I didn't notice this before, but it looks like the bridge is not parallel with the stop piece. Maybe an optical illusion, but it looks like the string length is slightly shorter on the treble side:
    [​IMG]

    I used the posts that came with the new bridge, and it doesn't seem loose on the posts or anything. Weird.

    Any thoughts? It's really close, and once the drummer hits the crash cymbal it probably doesnt matter much, but I know, and it drives me a bit crazy.

    Thoughts? The action's low, so I could raise it (thinking that might extend the scale length a bit?). Anything else to try?
     
  2. C_Becker

    C_Becker Dat Gibson smell Premium Member

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  3. Paul46

    Paul46 Senior Member

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    It is possible to flip the saddles, but you'll need a small wrench/spanner to prevent the saddle nut from spinning. There's also a couple of tiny washers in there that are very easy to lose!

    I had the same problem with a Fender Coronado. In the end I had to dowel and re-drill.
     
  4. mux164

    mux164 Senior Member

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    Not a pro here but I'd try to flip the g staring saddle around, should be able to get it closer then
     
  5. Freddy G

    Freddy G V.I.P. Member

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    you could flip the whole bridge around.
     
    mux164 likes this.
  6. mux164

    mux164 Senior Member

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    thats why you are the man, I would have probably done what I said. And be cursing up a storm because it's way too fiddley.

    Thanks Freddy
     
  7. Telzilla

    Telzilla Junior Member

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    I was able to flip the saddle. Paul46 was right, there are some tiny washers in there. Problem solved.

    Just a general question- would the height of the stopbar (which I believe affects the string tension) affect the intonation?
     
  8. T00DEEPBLUE

    T00DEEPBLUE Senior Member

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    Raising the tailpiece doesn't affect the distance between the bridge saddle to the nut. So in that regard, it doesn't make a difference.

    However, if you're going to lower the tension of the strings by raising the stop bar up, the fact that the strings are at a lower tension at the same pitch means that that the strings will have a greater tendency to be pulled sharp in the action of plucking them. So to nail the ideal compromise of intonating the guitar to keep it in tune as much as possible under normal playing, you're going to need to move the saddles very slightly further back in an effort to try and compensate for this effect.
     
  9. scimitar

    scimitar Senior Member

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    I'm not convinced that is right, firstly altering the stopbar height does not mean that the string tension for a given pitch is any different, that is a given - for any scale length and string gauge the tension needs to be the same to get the same pitch. However what is different is the pressure on the bridge which affects how easily the strings slide over the bridge if the tension is increased, this makes the string length effectively longer which should actually reduce the amount the pitch raises when fretting - so I would suggest that the saddle would need to move slightly towards the nut for proper intonation?
     
  10. T00DEEPBLUE

    T00DEEPBLUE Senior Member

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    EDIT: Never mind. You're dead right. What you're saying does make sense.

    Any degree of elasticity added to the string is going to move the saddles forward. Because any length of string that needs to stretch is going to need to stretch by an equal amount as another section. And by moving the tailpiece up, you're making the length of string behind the bridge more elastic by lessening the restriction of it's movement. This additional elasticity means that the pitch of a string isn't going to rise as much when it is bent the same amount, because the stretching of the string is effectively distributed over a longer length.

    This helps explain why higher tension strings have their intonation points moved further backwards. Because higher tension strings are generally less elastic, so they cannot compensate for the increase in tension by stretching as much when the strings are fretted. Thus they rise in pitch more, and so the saddle has to be moved back to compensate.
     
    Last edited: Sep 29, 2017

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