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Hot rodding a J-45...know anyone?


mountainpicker

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I was just over on the AGF and caught a thread on Bryan Kimsey hot rodding Martins, especially D-28's, see his site here http://www.bryankimsey.com/

and was wondering if the Gibson world has an equivalent kind of guy that is into doing some of the same things to get the most out of a J-45/50?

 

Kimsey is so well-known and respected on UMGF. He is really a neat guy too, and has had to overcome some of life's worst adversities.

 

Typically those with 70's Martins will send them to him - he does great neck sets, corrects the often misplaced bridges to correct intonation, plays with a Popsicle brace - although I don't know what that is, and shaves a brace here and there. Neat stuff. I wonder if he works on Gibsons - I think he doesn't because the neck sets might be more difficult, but I could be remembering wrong. Couldn't hurt to ask? Maybe he will do some of the other stuff.

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There are some guys out there doing some serious re-working of Harmony Sovereigns, replacing the ladder bracing with scallop X bracing and such.

 

I would say a lot could be done with 1960s and 1970s J-45s. Bridge and bridge plate replacements and trying to get a bit wider string spacing on the 1960s guitars while those made in the 1970s would certainly benefit from some brace shaving. But it seems like a wiser move just to avoid those guitars unless you absolutely have to have a "vintage" guitar with a thinner neck. I have had popsicle bracing added to Schmidt-made guitars and the bridges re-positioned on a couple. Did not see this as hot-rodding though but more taking care of inherent structural issues. I do not buy a guitar anticipating "improving" how it sounds or making it into something other than it is. If it does not have what I want I will go find a guitar that does.

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MP, the best way to find out if Bryan K has ever modified a J45 is probably to just hop on the IMGF and ask him. I have little idea of what one might do. It seems to me that the "popsicle" brace, that runs straight from top side to bottom side at the top of the sound hole, must be there for a reason - structural integrity? I think that brace has been o every guitar I've ever owned.

 

Shaving already scalloped braces? Perhaps sound could be modified to some extent. Hmmmm. But there's no "going back" once this has been done. I think many of the instruments BK works on must be straight braced D-28s. From my limited play of those instruments, I do prefer the scalloped HD 28s over the straight D-28s.

 

The 2 j-45s I have (TV and Legend) are good the way they are, I can't imagine what "hot-rod" mods might do. Interesting thought. Perhaps one could take a Norlin Era 45 and try and lighten up some of the bracing to make it less "thuddy" ?

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It seems to me that the "popsicle" brace, that runs straight from top side to bottom side at the top of the sound hole, must be there for a reason - structural integrity? I think that brace has been o every guitar I've ever owned.

 

 

If you have ever owned a guitar without them tops without a popsicle brace (at least on ladder braced guitars) can buckle.

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Browsing around The Interwebs, its looks much of what he does is set-up and parts: "tweak the nut and saddle, slot the bridge, replace the pins with black water buffalo horn, dowel the tuner holes". He'll also "slightly shave the back braces, and the controversial removal of the "popsicle brace" (which as noted, voids the warranty).

 

re the prose and vcon of popping the posicle, here's BKs take: "Popsicle brace removal: The popsicle brace is a long flat brace under the fingerboard (See one!) that was added in the late 40's to help prevent cracks where the fingerboard lies on the top. This brace inhibits vibrations coming down the neck from working the upper bout. Removing the popsicle brace will give you a slightly more "airy" and complex sound. The most common comment I get is "my guitar sounds 10 years older". There is a litle risk involvee: There may be some small gouges and scrape marks. Most of the time, the braces will come out quite cleanly. Other risks include potential for cracking in years to come. Pre-war Martins and many modern guitars do not come with the popsicle brace at all."

 

and here vox contra from FRETS: "Many of us "old-timers" feel that the area above the soundhole is not particularly significant in resonating, but instead is more important to the structural integrity of the instrument. Too many folks presume that because some of the "golden era" Martins were made without the brace, that removing it in the modern ones would capture that old sound. [back then] the brace was simply left out after the switch in 1930 from 12 to 14 frets (the body was shortened so they just left the brace out). I'd bet that they reintroduced the brace after noticing the tendency for the top to crack along the edge of the fingerboard. As a repairman, I've sometimes added an extra wide version of that brace on an instrument that was made without one, to stabilize a cracked top. I've not heard a comment about the change in tone, and have noticed none myself."

 

You decide, as the man says, but it soudns like that mod might be a case of making a fetish of vintage detail at the expense of the long term life of the instrument.

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As long as its been brought up, I am curious about two things:

 

1.) Would pre - 1950 Gibson owners take a peak and let us know if there IS a "popsicle" brace?

 

2.) Anyone here actually have had a Bridge 'slotted" Any observations? I am of the mind that it would make little difference. The reason I say this is because my custom shop SJ was slotted, but I did not note any easier string install or discernible properties that made me want to do it to any other guitars.

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As long as its been brought up, I am curious about two things:

 

1.) Would pre - 1950 Gibson owners take a peak and let us know if there IS a "popsicle" brace?

 

 

Well, my L-OO Legend, which is supposed to have exactly the same top bracing as its 1937 predecessor, has one.

 

My 1948 J-45, unfortunately, has a 1968 Gibson-replaced top, which has the popsicle brace.

 

Structurally I believe its primary function is to prevent local buckling, as well as reducing the chance of sheer fractures of the top grain next to the neck. This area has a lot of compression load generated by string tension on the neck, which is complicated by that gaping soundhole interrupting the top box-beam flange (the soundboard). Purely from an engineering perspective, the top of an F-hole guitar, or one with an offset soundhole, it probably stronger.

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From Mr Kimsey himself:

 

 

 

http://www.bryankimsey.com/popsicle/

 

 

 

 

BluesKing777.

Ah Ha ! Brace #1 is what I've always (erroneously) assumed was the "popsicle brace. Not correct - thai you BK and BK. Perhaps the Gibson folks don't even use the true "popsicle brace - as per Tony's video review of Gibson bracing patterns: http://musicvilla.wpengine.com/gibson-acoustic-guitar-bracing-explained/

 

Note: I do not have any Kentucky Bourbon in the house, so am not able to "imbed" the video. [biggrin]

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Perhaps the Gibson folks don't even use the true "popsicle brace - as per Tony's video review of Gibson bracing patterns: http://musicvilla.wpengine.com/gibson-acoustic-guitar-bracing-explained/

 

 

Yes, they do. At least it's there on all three of my Gibson flat tops. Unless you have the strings off, you can't get your hand in there to feel it, but you can certainly see it with an inspection mirror. "Popsicle brace" is an appropriate term because it's shaped more or less like a popsicle stick. It's not a brace in the traditional sense. It's pretty much like the centerline back cleat, backing up an are that may have an inherent weakness.

 

From an engineering perspective, I think two things are going on. String tension on the neck is trying to shear the top grain alongside the fingerboard, and that same tension, because it's not applied along the neutral axis of the neck, is trying to press the fingerboard down through the top as it bends the neck up at the headstock.

 

In any case, some variant on the popsicle brace probably makes sense.

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With Gibsons, I've always seen the small brace that is sometimes positioned between the bottom of soundhole and the intersection of the x brace referred to as a Popsicle stick brace, as it is about that size. Reinforcement strips like this always seem to be to the left and right of the sound hole, but are sometimes below it, too. I guess it stands to reason that any flat strip of wood used to reinforce the top could be called a Popsicle stick.

 

Red 333

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B. Kimsey is a great guy with loads of knowledge and theories. Very straight and focused - not much fikumdileikum.

 

I been lucky to communicate with him several times and have learned a trick or 2.

 

He usually doesn't see'n'touch many Gibsons. .

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Here fx, is a part of our exchange about the popsicle brace - no harm done in bringing that further. .

 

Me :

But how exactly does that stick influence sound. Hard for greenhorn me to

imagine as the shoulders seem to be a terrain vague when it comes to acoustics.

 

Mister K :

What's attached to the upper bout? The neck. The more vibrations you can

send down the neck, the more the upper bout will vibrate. Thus, if you

leave the big heavy tuners in place, you might as well leave the popsicle

alone.

But remove the tuners and you immediately make the neck stiffer (in archery, using 125 grain tips vs 100 gr vs 85 gr will change the stiffness

of the arrow dramatically). Stiffer neck puts more vibrations into the upper bout.

That's the hypothesis anyway.

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Thx, Em7. Interesting to hear Bryan Kimsey's thoughts about this, and another discussion that was recently on the forum. Was the tuner-weight-as-a-factor comment initiated by Mr. K?

 

Also of interest: On the Kimsey site, the Chladni Plate images of differing frequencies, used supposedly to look at effects of bracing changes to guitar tops. Could something like this help to quantify ANY change in a guitar before/after the controversial ToneRite device? Sand or filings sprinkled on a guitar top would make an approximation of the Plate when the ToneRite was in use. Maybe a photo 90sec in, vs 9 days later. Not that any observed change in the Chladni Plate image would correlate to a more "opened up" guitar, but as it stands now, most ways of attempting to prove any value to ToneRite are fairly subjective.

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Here fx, is a part of our exchange about the popsicle brace - no harm done in bringing that further. .

 

Me :

But how exactly does that stick influence sound. Hard for greenhorn me to

imagine as the shoulders seem to be a terrain vague when it comes to acoustics.

 

Mister K :

What's attached to the upper bout? The neck. The more vibrations you can

send down the neck, the more the upper bout will vibrate. Thus, if you

leave the big heavy tuners in place, you might as well leave the popsicle

alone.

But remove the tuners and you immediately make the neck stiffer (in archery, using 125 grain tips vs 100 gr vs 85 gr will change the stiffness

of the arrow dramatically). Stiffer neck puts more vibrations into the upper bout.

That's the hypothesis anyway.

 

I'm not sure if he is saying that reducing the total mass (weight) of the neck by going to lighter tuners will stiffen the neck, or if reducing the mass at the end of the neck (drawing on his arrow analogy), once again by going to lighter tuners, is what you are after. In other words, is it total mass, or the distribution of total mass, that is causing increased stiffness, which should translate into improved transfer of vibration?

 

Along similar lines, I watched a video today comparing the tap-tones of various fingerboard materials, which was quite interesting. There's certainly a lot that goes into determining the final tonal character of any guitar, and it has given me a better understanding of how nominally-identical guitars (shape, tonewoods, construction) can have significant variations in character, even when there is a strong family resemblance.

 

I've become interested in the physics/engineering of guitars recently, probably the result of a bit too much free time. I should be practicing more instead.

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I withdraw this post and rethink - stand by. .

 

 

Em7, I'm not disagreeing with you. Just trying to figure out the physics of what he seems to be saying, which would suggest that you want the lightest set of tuners possible. Think of all those poor old D-28's out there with those heavy rotos on them.

 

Would they be better with waverlies, or sta-tites?

 

Serious questio9n, actually.

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Em7, I'm not disagreeing with you. Just trying to figure out the physics of what he seems to be saying, which would suggest that you want the lightest set of tuners possible. Think of all those poor old D-28's out there with those heavy rotos on them.

 

Would they be better with waverlies, or sta-tites?

 

Serious questio9n, actually.

 

But Nick - I haven't chestnuts in this fire - was only listening and trying to learn.

 

Believe I got him wrong in the first place, , , and can't get him right in the second (now !).

 

 

 

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But Nick - I haven't chestnuts in this fire - was only listening and trying to learn.

 

Believe I got him wrong in the first place, , , and can't get him right in the second (now !).

 

 

I'm not sure if you got him wrong or not, but I'm not sure if his analogy is correct. I don't know the physics of an arrow in flight, but we've all seen super-slow-motion film of an arrow being released, in flight, and hitting a target. There is certainly a resonant frequency to an arrow in flight, I'm just not sure how it translates into the vibration of a guitar neck. He may be onto something, but it's really hard to sort out.

 

And a guitar neck certainly vibrates when you hit a string.

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I'm not sure if you got him wrong or not, but I'm not sure if his analogy is correct. I don't know the physics of an arrow in flight, but we've all seen super-slow-motion film of an arrow being released, in flight, and hitting a target. There is certainly a resonant frequency to an arrow in flight, I'm just not sure how it translates into the vibration of a guitar neck. He may be onto something, but it's really hard to sort out.

 

And a guitar neck certainly vibrates when you hit a string.

 

I'm not interested in the arrow analogy really.

 

When I first read the hypothesis, I concluded that heavy tuners would make the neck vibrate so much that it would equal out the effect of the removed popsicle brace

 

Now as I re-read, it gets diffuse. Here's my continued original response to which he didn't oppose -

 

Mister Me :

Quite a piece of math there, but guess the bottom line is that heavy tuners make the neck vibrate more and thus equal a taken out popsicle-b.

In other words : If you go to lighter tuners, fx ovals, then it's reasonable to remove the pop. That is of course, if you want more high shimmer, , , , which I btw. don't.

 

 

 

(notice that removing the popsicle primarily should affect the high end).

 

 

 

 

 

 

 

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Tell Mr. K we're all messed up on this, here, and could he please join us. Unfortunate that he did not comment on your heavy make the neck vibrate more part.

 

As the 10 lb ball of clay is not currently handy, a fun little experiment is to clamp the fretting hand firmly over the top of the headstock, where the clip-on tuner normally goes. Grip with a few pounds of pressure. Now, give a few open strums, alternating between lighter and heavier ones. Listen for any change in tone at the end of the decay. Grip on and off as the notes decay. Lighter seems to be more noticeable.

 

 

damping.

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Thx, Em7. Interesting to hear Bryan Kimsey's thoughts about this, and another discussion that was recently on the forum. Was the tuner-weight-as-a-factor comment initiated by Mr. K?

 

It was, yes. . .

 

 

Tell Mr. K we're all messed up on this, here, and could he please join us. Unfortunate that he did not comment on your heavy make the neck vibrate more part.

 

 

Not a bad idea, , , let me try. . .

 

 

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