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Thread: Bridge location on an A5 build

  1. #1
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    Default Bridge location on an A5 build

    I am starting an A5 style mandolin, and based on suggestions from the forum I got a copy of Adrians F5 plans, and the A2 plans from GAL with the understanding is the shape is from the A2 and the top and back gradations are best from the F5. In laying the gradations on the A2 body I am finding the bridge is not located on the center of the dome, and it is also not located in the widest part of the body. I recall reading a thread about this but have not been able to find it. Can someone give me a pointer to it?
    Thanks a lot
    Bob Schmidt

  2. #2

    Default Re: Bridge location on an A5 build

    Search "Griffith" Lloyd Loar A5.
    Seems like there was quite a bit of information on the Girouard's website on that mando, too.

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  4. #3
    Adrian Minarovic
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    Default Re: Bridge location on an A5 build

    The A style body from teens was not designed for f holes and long neck so you need to make some compromises. You can have a look at the Griffith Loar A-5 to see how folks at Gibson did it but I myself prefer some modern approaches both from structural point and design point of view.
    Keeping the neck sama as F-5 (including forward shifted position of crosspiece) will move the bridge way forward and you either need to adjust arching so the apex is closer to bridge (like Kentucky KM900 series did) or leave it and live with the bridge on the downhill - this is probaly what folks at Gibson did on the Griffith. Both have advantages and disadvantages. The large area behind bridge is prone to bulging out under string tension. On the KM-900's they widened the resurve under taipliece to move the arch forward and that place is also spot of potential weakness if left thin or carved too deep. They tend to have deeper voice (somewhat thumpy) because of this large open area and smallish f holes.
    If I were to make Griffith copy with long neck, I would at least partially move the arch towards bridge without widening the recurve, which would require somewhat flatter curves from tail to bridge and/or adjust thicknessing to stifffen the area behind bridge. Perhaps I would move tonebars to more parallel position (closer to centerline towards the tail end) and leave the spine of back a bit thicker from tail to bridge.
    My personal favorite approach is also shortening the neck a bit - I think 14th fret at crosspiece should be OK and keeping the crosspiece down where ovals have it would move the bridge 1/2" down making the whole thing more balanced and giving a bit more space for f-holes allowing adjusting their size.
    Most modern makers just shrink the body a bit so it can be overlaid over F-style with the same neck/ arching geometry.
    Adrian

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    Default Re: Bridge location on an A5 build

    Siminoff sells a set of "Mrs. Griffith A5" plans, and they're comprehensive.

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    Default Re: Bridge location on an A5 build

    The discussion on the Griffith A5 was what I remember reading, I will go back and take a look at it now that I have studied the 2 sets of plans a bit it will make more sense to me. Using the 14th fret sounds like an interesting approach to consider, that would put the bridge closer to the apex and perhaps ballance it a bit better.
    I have already cut the top, but have not started to carve it yet so it would also be possible to reshape it a bit and make another mold.
    Thanks a lot
    Bob Schmidt

  9. #6

    Default Re: Bridge location on an A5 build

    I don't think it matters as much as you might think. Speaking here of JUST the bridge position, obviously all these decisions (location of bridge, body shape and size, sound hole shape,size, and location, bracing, arch height, graduations) all add up.

    Here's one with a 15th fret neck joint:


    And another one with bridge placed on the crown of the arch:


    They sound a little different, we're talking about different woods and graduations (redwood over soft bigleaf maple vs. Alaskan yellow cedar over similar soft bigleaf maple). If anything, the mandolin with the "non-optimal" bridge position is louder (not that I would attribute it to that bridge position).

    Just my two cents - in my opinion, moving the bridge forward or back a couple centimeters is not a Huge Deal.

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  11. #7
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    Default Re: Bridge location on an A5 build

    Quote Originally Posted by HoGo View Post
    Keeping the neck sama as F-5 (including forward shifted position of crosspiece) will move the bridge way forward and you either need to adjust arching so the apex is closer to bridge (like Kentucky KM900 series did) or leave it and live with the bridge on the downhill - this is probaly what folks at Gibson did on the Griffith.
    Adrian, do you have any opinions on why this seemingly suboptimal bridge placement seems to work so well acoustically? Mrs. Griffith has a lot of fans, and not simply because she’s the only Loar A5, as do her modern tributes.
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  13. #8
    Adrian Minarovic
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    Default Re: Bridge location on an A5 build

    Quote Originally Posted by pheffernan View Post
    Adrian, do you have any opinions on why this seemingly suboptimal bridge placement seems to work so well acoustically? Mrs. Griffith has a lot of fans, and not simply because she’s the only Loar A5, as do her modern tributes.
    All of this is purely subjective. Just like evaluating sound. I can offer some OPINIONS. I never played the Griffith A-5, just listened to the recordings closely (especially on Grismans Tone poems you can compare it to bunch of others) and I guess VERY few people actually had a chance to play it in person as the mandlin is locked somewhere in an instrument collection. I played bunch of the KM900s that are modelled quite close to Griffith A and they show some common timbre. It's hard to describe by words but I would call it thuddy somewhat muddy "woof" behind the string. Of course much depends where and how you attack string but generally. There's the impression of volume with the woof behind each tone but I didn't make any direct comparisons or played with others to see if it cuts. I personally like the typical F-5 tone more than this but sure many folks like the bassier tones and makers like Gilchrist deliver that modern BG tone very consistently even on F-5 (the video comparison of Nuggett, Gilchrist and one of mine from few months ago shows that at least to my ears). To me the instrument is fine but is just one experimental piece we don't know what would happen if they built whole batch of these or many more. There are inconsistencies among F-5's so perhaps some of these would not be favored as much as this existing one. The sample is just too small to do any definitive conclusions.

    For me as a builder however the structure doesn't seem very stable. Perhaps from this viewpoint we could call the placement suoptimal. They just did what they were asked for and stuck F-5 neck on A body and cut f holes within the limited area it offered. We don't know how they carved the arch of the top but they likely recarved prepared oval hole top. From the pics I've seen (and they are posted on MC as well) I think there's at least some degree of bulging under tailpiece going on - even most ovals have it though the brace above bridge acts as leverage point and bulging occurs only closer to tail block under tailpiece.
    I've seen many mandolins with collapsing or bulging tops and I would like to avoid that in my builds. Many of those mandolins were built quite thin to start with (and Griffith is certainly not overbuilt) and the large open area just begs for bulging and center seam breaking. As a maker I would be a bit nervous to send that out as the tops are typically carved very close to the structural limits and you players don't have to add too much negligence to cause problems. I carve my tops with apex right under bridge but after some time the arch just deforms and the apex "moves" a bit south on every one. I get to see some of my mandolin regularly and I see this effect within 10 or 15 years. Even on newly strung mandolin the top will no more fit the arch template. Wood is plastic in the long term and I want my mandolins to work a long time.
    Adrian

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    Default Re: Bridge location on an A5 build

    Thanks for the comparison Marty, they are both beautiful instruments. More food for thought. I do like Adrians reasoning from a geometry standpoint it makes more sense to have the bridge on the apex, so I will probably work towards that goal.
    Thanks a lot
    Bob Schmidt

  16. #10

    Default Re: Bridge location on an A5 build

    And just where is Mr. Condino?
    No doubt pushing his bicycle up some mountain road in Valle d' Aosta.
    He's been promising a technical package on the Griffith A, for what seems like years...
    I am not tired of this investigation into the Griffith A.

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    Default Re: Bridge location on an A5 build


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  20. #12
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    Default Re: Bridge location on an A5 build

    Looking at this a bit further, is there a reason the 15th fret marker is placed where it is or can that be moved which would put the 15th fret on the marker although in reality it would be around the 14th fret location if it we to stay in the place on the A2 plans. Does it have to do with the size of the headblock and the extension placement?
    Thanks a lot
    Bob Schmidt

  21. #13

    Default Re: Bridge location on an A5 build

    Bob - The world is your oyster (or bag of popcorn)!

    The "15th fret" on your new mando will be where you put it, or the nut, or the bridge. They are related and cannot be considered separately. They also relate to the top plate geometry, as Marty and Hogo suggest, so all these points have to be considered together to sort out the geometry and placement on the mando.

    It sounds like you are doing it, but just to make certain I'll mention the suggestion often offered from Sunburst: draw it out to scale to sort the geometry and sense of how it comes together.
    The Griffith A-5 had its 15th fret way up north near end of the nose of the A model. If you move your new nut-15th fret-bridge trio to register the 15th fret somewhere between where Griffith was and the old A-model at 14th fret you should be golden, huh? This brings up the question of what kind of neck joint you intend to use...it's all connected...

    Mr. Condino traded his bicycle in for a 100-year anniversary Moto Guzzi...apparently no help coming from him any time soon.

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    Default Re: Bridge location on an A5 build

    I am currently thinking of using a dovetail joint, but will probably do a bit more research.
    Thanks a lot
    Bob Schmidt

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  25. #15
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    Default Re: Bridge location on an A5 build

    Mr. Condino? Is my grandfather or father on the mandolincafe now?????

    Me thinks that the popcorn button has evolved into more than just dissin' on vegan snackfood around here!

    I'd likely be pedaling the Valle d' Osta, rather than pushing my bicycle...and the ancient little village of Condino is in Trentino, so more likely to find me hanging around there!

    My dream gig is the Festival of Sound in Val de Fassa, pretty much in the neighborhood: https://www.fassa.com/EN/Main-events...the-Dolomites/

    As for the Griffith A5....well...there is nothing that I nor anyone else has said about it that cannot be found with the search button. There is extensive commentary on it from folks who know, including some crumudgery & disagreement.

    Yes, I have had it in my hands & nerded out with hacklinger guage and measuring tools and played it hard.....that is where the greatness lies. Playing it. In my humble opinion, having played close to 50 of what many would call the best Lloyd Loar signed F5s in the world, many with significant provenance and famous player-itude attached to them, the Griffith is one of the top 5, perhaps top 3 Loars in the world. If it had a scroll, there would be no conversation. But it does not, so scroll wankers aghast and abound. The simplicity in the well executed design and the beauty in voice are what attract me to it. In our ever increasing world of complexity, simple clean designs are refreshing. #@$%!!!! In addition to mandolins and the guitar family, I build double basses- I don't need more complexity in my woodworking life!

    I have plenty of notes and documentation that would make for a very nice technical paper on everything I can tell you about it, but guess what? Whenever I submit it to an editor, the response is always,"...but mandolin players only care about F5s and scroll envy and such, so it will never sell or have commercial merit." Every student that visits my shop gets extensive access to all of that information and literally hundreds of more significant instruments and very cool practical application of how to use it in your mandolin builds.

    Physically, I could care less if the binding is the same as Herbert Hoover's binding or if the the ghost of _________ ________ can be seen in the old varnish, or any other non musical hogwashed unicorns and fairy dust. What I want is mellfiluous magnitude and harmonious balance and an instrument that inspires me to play beyond my current levels of satisfaction with ample variance in the tonal spectrum and enough headroom that non mandolin players inquire, "Ooooohhhhh. What is that? I've never heard a mandolin sound that nice! You nailed it on that one!"...and may absolute favorite: the rare moment when the guitar player shouts out for someone else to not play so loud (!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!). The Griffith has all of these and scads more.

    Unfortunately for the rest of us mortals, it is currently locked up in private hands that are extremely difficult to get access to which complicates mandolin-ness for the sake of bettering the craft or the future of such instruments.

    From a technical standpoint, the Griffith is a one off custom order instrument where by the folks at the factory just grabbed what was handy, put them together as fast as possible, and then moved on to the next instrument. Anyone that has ever worked in a factory understands that- no unicorns and fairy dust to sweep up back into mythical little boxes for the trolls at the end of the night. Very few builders that I know attempt to copy it down to every last detail because....well...why??? Just so you can waste endless hours of your life on anal retentive details from 100 years ago??? Like it or not, the F5 has become the industry standard, so it makes more sense for modern builders to keep most of the build geometry the same and just modify the shape. Nobody is getting rich making mandolins, so keep production efficient.

    If you don't like the neck joint, change it. If you want a different air volume, change it. Old Lloyd would have endlessly laughed out loud at the dogmatic insistence on stopping with his designs. He was a constant tinkerer and creator who always pushed the limits on an eternal search. You are going to spend a couple of hundred hours building a mandolin. Take the essence of what history showed us and then lighten up, have a little fun, inject some of your own personality into it. There are already 1000s & 1000s of same old same old baby s#!t brown mandolins out there.

    Don't be afraid to think for yourself. If that is not you, then just take the photos, and all of the information that is readily out there, and blindly make a copy as best you can. Guess what? They will both sound like pretty good mandolins. I find body cavity air volume, plate / neck dimensions, and neck angle geometry more important than moving a fret or two.

    As for my A2 plans being different- that was the whole point- it IS a different instrument, so of course the layout is different....as are the neck and the plates and almost everything else. There is a giant paragraph of text printed on page one to go with the spirit of the design, not to clone it...


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  27. #16
    Adrian Minarovic
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    Smile Re: Bridge location on an A5 build

    Here it is! Mr., ehm, James, we didn't expect any less from you :-).

    I don't doubt the Griffith A sounds great but we will likely have no chance to try it anytime soon. :-(
    Whether this design is worth coping closely is everyone's own decision. Builders have to sell for living and F-5 is time proven model for sound and sales. Griffith, being one-off build in a factory may not be a good representative of how that model will generally sound, could be just happy accident.
    I'm not in the US and don't live out of building so I can build whatever I want but I happen to love the F-5. I have enough information to create quite faithful Griffith A-5 styled mandolin, but with my limited space and time this has to wait.
    I wonder about the Girouard Griffith in works? I haven't heard about that for a long time...

    BTW, James, didn't you consider publishing the info you have yourself? I did that with my F- drawings. Didn't have to ask anyone to publish. I would certainly be interested in getting a copy whatever it is. One can never have enough first hand information.
    Adrian

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  29. #17

    Default Re: Bridge location on an A5 build

    "Here it is!" Indeed.
    I had to poke the bear, twice, to get it.
    (Don't misunderstand my ribbing. I enjoy the stories and geography. I would love to get to Northern Italy. Or Banska Bystrica - the images on the computer of that town look lovely...)

    I may have made an error in my thinking that Bob is intending to build his mando along the lines of the Loar A-5. That was why I was pushing to get James involved.


    Was the Loar A-5 neck joint a tapered dovetail?

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  31. #18
    Registered User j. condino's Avatar
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    Default Re: Bridge location on an A5 build

    Yes; standard issue Gibson tapered dovetail from that era.

    Build one. It is a cool design and the results are surprisingly good for a modest effort.


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  33. #19
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    Default Re: Bridge location on an A5 build

    Thanks for all the comments.
    I play Irish trad music, and I have an older Gibson A that I use for that. It has a nice sound but is a bit overpowered by fiddles and pipes. My interest in building an A5 is to make a comparison and see if I can get a bit better projection in a session setting.
    I don't have a particular initerest in copying the exact details of the Griffith. Since I am a new builder it is the basic fundamentals of building that I am concerned about.
    I have no problem with adapting different stratagies, and have already had to do so in small degrees to compensate for mistakes, but you have to understand basic mathamatical principles before you tackle calculus and likewise in this craft, the basic principles of sound design are what I am looking for. The cafe has been a tremendous help in that regard, and I really appreciate all of the input.
    Thanks a lot
    Bob Schmidt

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