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[quote="Jake Archer"][The design with the JLD is basically, what you see is what you get. There aren't really any secrets with it..
quote]

I was wondering, since the weight issue comes up quite a bit, what would happen if you cantilevered the block to the North? Wouldn't more of the weight be hanging off of the front of the bridge? Might change something tonally for better or worse? Or if you reversed it and had the weight hanging to the South? And it would weigh less because the rod would be shorter? And with the option of leaving it hanging straight down, that would be three ways to do it on one guitar? And if you made two sets of each, one out of mahogany and one out of bass wood, six ways to do it on one guitar?





Why does the big hunk of wood have to hang down so low? I would change the name of "big hunk of wood" to "slimline tone enhancer" or something like that. If it was shorter leaving the rod closer to the bridge, wouldn't it take more force on the rod to rock the bridge flat? Hence driving more of the vibrations or whatever into the tail block? Or would it need to come down so far to find a sweet spot that works better? And would it change anything if the rod hit the tail block by the top, in the middle, or on a piece of homemade kerfing with a hole in it where the back and the tail block meet? One way might leave the guitar more responsive for finger style and one way might leave it better for heavy strumming?

I could do all of these experiments myself but, since you are right there thinking about it and doing it anyway?

Glen

I dont see much difference in how the weight of the unit hangs .. its still just a mass hanging from where ever the thing attachs. If it was heavy enough, liek a piece of steel, then it would impart its own torque to the bridge - but not made out of spruce - too light to really ahve an effect. Making it shorter wont do much either IMO, the reason its longer in the first place is simple physics .. torque = force x distance ... so with the longer piece hanging from the bridge, the less force it will take on the rod to correct the top's belly - which is what these things were designed for in the first place.

Note - David doesnt use it to correct top belly in his baritones - he uses it to alter the attack of the notes. I like the way mine sound the way they are .... so no JLD for me.

I also dont see how where it hits the tail block will make any difference in tone ... the tail block adds nothing to the tone of a guitar, its pretty inert I would think ...

Also your S shaped piece will actually weigh more than if it were just straight like the real thing ... so making the rod shorter is offset by the added wieght of the block.

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Tony Karol
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Hi Tony

Thank you for the response.

I don't see much of a difference on how the weight of the unit hangs either. But it might make a difference. And it might not. What's a couple of grams one way or the other? But when you strap strings to it and hit the big E chord, it might make more of a difference when the thing is bouncing around all over the place. Then again it might not. Maybe it should be made heavier to impart it's own torque on the bridge one way or the other? Who knows?

I'm not thinking that we are going to put a bridge doctor in a Gibson L1 and have it blow away all of the guitars at the next Montreal guitar show. I don't think that that is going to happen.

Actually I could care less if someone put a JLD in one of their guitars or not. But if someone brought a guitar to my shop that needed one, I would certainly like to have some info about what to do, and what not to do, with one before I went hacking into someone's family heirloom. That one I would care about. A lot.

For example: Say someone had an old guitar that they wanted to, or needed to, put in a JLD. If installing it one way killed 15% of the total responsiveness of the guitar, and installing it another way only killed 5% of the total responsiveness of the guitar, wouldn't it be nice to know which direction to head for from the start? And what if someone figured out how to make the guitar 5% more responsive with a little bit more bass with one? And then shared their findings with someone else who in turn learned something else from it? Wouldn't that be cool? It probably wouldn't make the Gibson king of the next Montreal Guitar Show. But it should make the owner of the Gibson about 5% happier.

Less force on a longer hanging piece to correct the tops belly makes sense. What is the difference in poundage to correct a tops belly with the rod 2" from the bridge as opposed to 3" from the bridge? How much poundage does it take to correct the belly in a top? Does anyone know? And how do you measure it?

"I also dont see how where it hits the tail block will make any difference in tone ... the tail block adds nothing to the tone of a guitar, its pretty inert I would think ..."

I would think that the tail block is not inert. When I play my guitars they vibrate from the end pin to the tip of the headstock. And the tail block is right in between those two points. If doing something as simple as cleaning the dirt off of a guitar, or changing the bridge pins from plastic to ebony, will change the voice of the thing, one would think that changing the tail block from bass wood to cocobolo should do something. One or the other should be filtering out certain frequencies more then the other. Let alone stabbing it with a rod that is connected to a big heavy block hanging from the bridge. We all know what happens to the tone when we add weight to a tail block.





I don't believe that the S shaped block is going to weigh more then the straight block. For one, I don't know how much a bridge doctor weighs. And I have asked. And I have not built an S shaped one yet. I'm pretty sure that with some space age technology and some hide glue, I should be able to laminate something together that is just as strong and lighter then a square block. Maybe T shaped. The part that hangs down only needs to be wide enough to hold the rod? And maybe drill some holes in it to make it lighter yet. Which might make it strong and flexible. Which might work better yet.

I'm not trying to be argumentative. I was just wondering how these things work because, I have one of my guitars that someone left in the hot car in Arizona with medium gauge strings on it about 500 times. And it is going back for more. I may need to be putting one of these things in it soon.

Thank you for giving me some more things to think about.

Glen

The earliest Breedloves had bridge trusses made in house. These were a wider block that tapered both back and down and had a smaller dowel. Then there was an adjustable, i.e., distance between the two contact points, that was made with wood and PVC -- not the best system. Then they changed to the current model which isn't perfect, and I modify mine.

I'm not sure what advantage one would get from the aforementioned "S" shaped block. There's more than enough leverage as it is. I think adding mass would be counterproductive. You're already adding probably 20g extra weight that you would otherwise no have, and you have the resistance of the dowel resting on the endblock. Properly adjusted, this dowel is only tight enough to keep it from rattling and the dowel can be rotated by hand with no string tension. Adding mass would further restrict vibration. If there was a way to have it functional and not have it be as heavy, that would be better.

Another reason for the long block is so that the dowel can be below the centerline of the endblock so there is room for the end pin or jack.

Some good ponts David ....

on my previous post .. the unit, if the width is the same , has to weigh more in the S shape - there is simply more side area vs a straight one - might not be much, but its there.

does adding mass via the cam clamp anywhere else on the body edge do the same thing ?? - if so, then the neck block really has no effect - its purely the mass of the clamp. I understand the sides vibrate, that makes a bunch of sense, but they dont add to the guitars tone like a back or top does.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Can this bridge doctor be used on a lattice top classical? I have e that has a rolling bridge. The a guitar top below the bridge is raised a bit and is indented slightly in front of the bridge. Pats post of a TUBBY sound with little sustain is exactly what this guitar has. Is this a potential fix?
Kent Bailey

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So if I reversed the rod making it pull from the neck block instead of pushing from the tail block that would change the tone???????????

I guess I have some experimenting to do?

Thanks!

Glen

Kent, the guitar is tubby probably because its underbraced in some fashion. You might try using different strings, higher tension and perhaps composites. This will help. The Bridge Doctor wasn't really designed for what you're dealing with.

Thanks D!

I suppose I could angle the rod any direction that I wanted to. Landing it just about anywhere inside the box that I wanted to. Might have to glue in a little block with a hole in it to keep the rod from sliding around. That would be easy enough to do.





Glen

Interesting: this discussion ranges from, "Those can't work", from those who have no experience with JLD, to, "Here's how they work", from those that do.

Breedlove guitars sound terrible, and have failed in the marketplace--and it's all the fault of the JLD, right? Heh heh...

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First:
A couple of grams one way or the other at the bridge can make a difference in the tone. I'd think keeping something like the Bridge Doctor as light as possible would be a good idea.

Second:
There's a world of difference between the forces the BD puts on the tail block, and what you get from adding a honking big clamp. I have known some very smart people, and good guitar makers, who added weight to the tailblock to reduce it's motion. The best one I know gave it up after a while, as it didn't seem to make much difference, but the reasoning behind it made a lot of sense.

The BD is mostly pushing the block in and out along the center line of the box. I've never seen a structurally sound guitar in which the block could move much in that way, so I question how effective that could be in producing sound. OTOH, these things are complicated enough that almost anything could happen. I'd want to see some good strong documentation, though.

[quote="Alan Carruth"]First:
A couple of grams one way or the other at the bridge can make a difference in the tone. I'd think keeping something like the Bridge Doctor as light as possible would be a good idea.
quote]

I would think so too. I wouldn't be above replacing the bridge with one made out of Koa to keep it all a little bit lighter. Having the rod pull from the neck block instead of pushing from the tail block, you could use a thinner rod? Saving some weight there too? But then the guitar community would probably scream like a gut shot cougar if you could see the rod through the sound hole. And you could probably save more weight, make the rod almost invisible, get the needed pull from the neck block that you needed, with a couple of strands of dental floss. And then there would be the big debate about what sounded better? Waxed dental floss? Or un-waxed dental floss?

I'm just thinking about how to put one into an existing guitar without changing the voice of the thing. Or, if it makes it better, that would be cool too. Or which way would be the least destructive to the voice of the thing. Any ideas of how to do that, or what not to do, from anyone, would be greatly appreciated. Of course, having no one else see or hear the guitar first, it would all be speculation at this point. But I'll take what ever I can get.

Thanks everyone.

Glen