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Thread: KM-900 and 950 bridge location?

  1. #1

    Default KM-900 and 950 bridge location?

    One of the distinctive feature of the Kentucky KM-9s is the location of the F holes. They are up higher toward the neck than typically seen. I think this is consistent with the original Loar (Lloyd) A-5.

    The bridge on the Kentucky 9s are centered on the F hole points, as is typical. But because the F holes themselves are closer toward the neck, likewise the bridge ends up closer to the neck. Basically the bridge is less centered on the body than we usually see. Or at least that's what my eyes and my crude scaling from pictures tells me.

    I know this isn't a problem. But I'm curious how the bridge/body ratios are seemingly different on the Kentucky K900-950 and still work. I'm missing something obvious here.

  2. #2
    Registered User brent1308's Avatar
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    Default Re: KM-900 and 950 bridge location?

    The scale is the same as most f-5 or a-5 style mandolins and the neck joins the body at the same fret, so the bridge is no closer to the neck than any other. The bridge may appear closer to the top of the sound board as compared with an F style because of the added percieved length made my the combo of the scroll and point.

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    Default Re: KM-900 and 950 bridge location?

    The bridge lines up right in the little notches of the F holes on my KM-900 and the intonation is spot on...As far as the bridge being in the center of the top it does appear to be closer to the fingerboard....I assume that is because before the A-5 the A models were all "short necks" and Gibson just made the tops the same and installed a "long neck" and that meant the bridge would have to be located closer to the fingerboard for the correct intonation.... that is just my opinion...

    Willie

  4. #4

    Default Re: KM-900 and 950 bridge location?

    Quote Originally Posted by Willie View Post
    The bridge lines up right in the little notches of the F holes on my KM-900 and the intonation is spot on...As far as the bridge being in the center of the top it does appear to be closer to the fingerboard....I assume that is because before the A-5 the A models were all "short necks" and Gibson just made the tops the same and installed a "long neck" and that meant the bridge would have to be located closer to the fingerboard for the correct intonation.... that is just my opinion...

    Willie
    That makes sense to me. Thanks Willie.

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    Registered User brent1308's Avatar
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    Default Re: KM-900 and 950 bridge location?

    Except there were no F holes to compare prior to the intro of the long neck. Maybe the lower bout is longer than in comparable A-5s. That I don't know.

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    Default Re: KM-900 and 950 bridge location?

    In comparing most A5's (my Dearstone included) and pictures of KM 900, it seems to me that most A's don't cut in as quick toward the neck as the old oval hole A's. The body shape of the 900's seem more like the old A's giving the illusion of the F holes and bridge being closer to the fingerboard. If memory serves, pictures of the real Loar a5 is shaped like the old Gibsons, so the 900 & 950 are a closer copy, at least in the loosk of them.

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    Registered User mandobassman's Avatar
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    Default Re: KM-900 and 950 bridge location?

    I believe Mandoplumb is right on the money. The KM900 has a "rounder" body than most modern A5's. Most modern A5s have a more gentle slope to the shoulders where the body joins the neck whereas the KM900 has a more drastic turn into the round part of the sides. I think this creates a optical illusion of the bridge being farther forward.
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  8. #8

    Default Re: KM-900 and 950 bridge location?

    Here is the Mandolin Store's link for all A-5 style mandolins. Scale a Pava, Breedlove, Lafferty, or Collings from the bottom of the instrument up to the bottom of the bridge. Hold that measurement and then start at the bottom of the bridge and see where the scale lands on the fretboard. It lands approximately at the 15th fret. Now do the same thing with the KM-900 and see where it lands on the neck. It's not around the 15th fret like the others.

    http://www.themandolinstore.com/scri...?idCategory=51

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    Registered User brent1308's Avatar
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    Default Re: KM-900 and 950 bridge location?

    Optical illusion. It definitely is the same length from the bridge to 15th fret, unless the mandolin in the picture is improperly intonated. But if you want to believe the 900 is shorter scaled, go for it.

    My 900 is a little less than 6 1/2 inches from bottom of the bridge to 15th fret. Same as on my F.
    Last edited by brent1308; Apr-10-2014 at 9:34pm. Reason: I measured

  10. #10

    Default Re: KM-900 and 950 bridge location?

    Quote Originally Posted by brent1308 View Post
    Optical illusion. It definitely is the same length from the bridge to 15th fret, unless the mandolin in the picture is improperly intonated. But if you want to believe the 900 is shorter scaled, go for it.
    I don't believe it is shorter scaled and I don't think I suggested that it was. Scale length if from the nut to the bridge. The measurement I am referring to is from the bridge to the bottom of the instrument.

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    Default Re: KM-900 and 950 bridge location?

    Since the same size top was used for the "long neck" A-5 as Gibson used for the oval hole "short neck" A models that meant the bridge would have to be moved toward the fingerboard and since they also wanted to use the little nooks in the FF holes to help line up the placement of the bridge the FF holes also had to be moved closer to fingerboard... In comparing my 900 with an F-5 I find that the FF holes are farther back on the top...Maybe just an optical illusion but maybe not.....A "short" neck doesn`t mean a shorted scale length, it just means the neck is joined to the body at a different place on the fret board...

    Willie

  12. #12
    Registered User brent1308's Avatar
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    Default Re: KM-900 and 950 bridge location?

    Quote Originally Posted by Canoedad View Post
    I don't believe it is shorter scaled and I don't think I suggested that it was. Scale length if from the nut to the bridge. The measurement I am referring to is from the bridge to the bottom of the instrument.
    I think I understand. You are saying that in all the other instruments, the distance between the tailpiece and the bridge is the same as that from the bridge to the 15th fret, but not on the Kentucky, making the lower bout longer? If that is the case, I measured mine and it is also just under 6 and 1/2 inches from the tailpiece (the bottom binding) to the bridge.

    Knowing that the scale lengths are all the same, the bridge would be closer to the dovetail joint on the A-5 with the longer neck than that of the short-necked oval hole instruments, but the bridge should be the same distance for all similarly scaled A-5s with the neck joint at the 15th fret. The lower bout between the bridge and the tailpiece could presumably vary, but I'm not sure it does based off of the measurements I took. By the way, my F is the same way, approximately equidistant from bottom to bridge as bridge to neck joint.

  13. #13
    Formerly F5JOURNL Darryl Wolfe's Avatar
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    Default Re: KM-900 and 950 bridge location?

    The original Loar A5 is the same size as the oval hole A-model counterparts made at that time. That shape has a considerable amount of length in the upper area of the body that the F-body does not have. On the F-model counterparts, that length is shorter. In short, the A-model body is longer than an F-model body. Modern builders, including Gibson generally base their A-model body dimensions off of the F-model to maintain the bridge in the center of the body

    One way of looking at the phenomena is this. If the Loar A-5 had an F-model peghead instead of the snake peghead, it would not fit in the Loar case of the period. It would be too long.

    Another way to look at it is this....the dimension from the nut to the tail end of the instrument is longer on the A5, although the fingerboard is exactly the same scale as those on the F5. In fact it's the exact same fingerboard.

    Gibson obviously simply determined the f-hole location on the A5 by pllacing them at the bridge as on the F-5

    So, the KM-900 is a nearly exact copy of the Loar A-5, not a contemporary A5

    Here is a photo I prepared a number of years ago...the most significant point is that the distance from the 15th fret/crosspiece to the upper end of the body matches the F-5 dimension.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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    Darryl G. Wolfe, The F5 Journal
    www.f5journal.com

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  15. #14
    Registered User brent1308's Avatar
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    Default Re: KM-900 and 950 bridge location?

    Of course, Darryl is right. I went back and measured with the ruler flat against the bridge down to the side of the tailpiece. It is a little less than 1/2 inch longer on the km-900 vs the f. 6 1/2 as I mentioned above vs a little over 6 on the f. Interesting stuff. The A-5s and their exact clones have a longer lower bout than most modern mandolins. So, now, when people debate whether an A sounds different from an F, do we have to specify a body type to account for the larger air chamber on the true a-5?

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