JS-1 intonation problem

swamp2

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I posted this over on talkbass, but then realized I might have better luck over here...

I've got this old ('73ish) short scale Guild JS-1 which was my first bass. I haven't been using it a lot in recent years as it's kind of a one trick pony sound-wise - but I realized it would be ok for the playing in church I do. So, thought I'd drag it out and fix a couple of it's warts. Made a new nut for it and put a set of GHS flatwounds on to turn it into a real thump monster.

Anyway, while setting it up, I found the intonation was a little off on some of the strings. No big deal, right? But on the D string, there's only so much motion of the saddle available as if you try to move it back past a point, the saddle runs into 1 of the 2 allen head screws that adjust the bridge height. I can't get it dialed in as it needs to slide back further than the bridge design will allow.

This is the old style hagstrom bridge with the wood saddles. Has anybody run into this? It's not clear to me I have any options other than changing the bridge or drilling holes which I'd rather not do on an otherwise clean vintage piece.

Thanks.
 

fronobulax

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Welcome.

I don't have a similar problem, as shown below. So either my ear is going or it is possible to get good intonation with the original bridge. How high is the bridge? Is it possible the neck is warped or you don't have the original saddles?

200%26_09_05_Guild%20014.jpg


200%26_09_05_Guild%20016.jpg
 

swamp2

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fronobulax said:
Welcome.

I don't have a similar problem, as shown below. So either my ear is going or it is possible to get good intonation with the original bridge. How high is the bridge? Is it possible the neck is warped or you don't have the original saddles?
Fronobulax, thanks for posting the pix. Very intersting. The bridge height adjustment screws on yours appear to be back quite a bit further than on mine. On mine, the distance from the adjustment screw (between the D & G string) to the bridge mounting screw near the bridge rear is about 1.5", and about 1 1/8" from the front of the bridge. Yours appears to be about 1/2 way between the 2 points. My saddles are a little further back than yours. I check the intonation w/ an electronic tuner, and compare fretted notes on the 3rd and 15th frets. Saddles, bridge are all dead nuts stock on mine, I'm sure of it.

Interesting...
 

fronobulax

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Hmm. After "Welcome" the most common phrase on LTG is "How about some pictures?". While waiting for yours, here's a '67 SF. Dimensions might be closer to what you have. I'll try and get measurements "soon".

200%26_09_05_Guild%20004.jpg
 

hieronymous

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Here's mine:
bridge1cq0.jpg

It doesn't look like it could possibly be intonated correctly, but it's good enough for me! Remember, though, that I play Gibsons and Rics too - as long as it's not a half-step off I'm usually OK with it.

I was thinking, maybe if you tried a different brand/guage of strings (lighter?) it might intonate better? Problem is, short-scale strings aren't the easiest to find...
 

dklsplace

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How was the intonation before you made the new nut? Slot depth/height can effect intonation as well.
 

fronobulax

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I wonder what the difference is between hiero's SF setup and mine. His bridge certainly has no room to push the saddles any further towards the bridge.
 

swamp2

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dklsplace said:
How was the intonation before you made the new nut? Slot depth/height can effect intonation as well.

I'd be happy to stick up a photo but I'm not sure where I need to stick it so it's accessible. Anyway, just to be clear - the intonation isn't so far off as to be unusable, but I'm an engineer by training so it just bugs me the design of this thing won't let me dial it in perfectly. If you look at hieronymous photo and imagine moving the D saddle back - well, you just can't. The slots in my bridge are cut so in theory you could, but the darned bridge height screw is in the way. That's the problem I have...
 

gilded

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swamp,

What is your action height? Why don't you measure it at the 12th fret, by giving us the space between the 12th fret and the bottom of the strings?
In 64ths, yet.

Also, are your strings old, really old, or new??

Are the strings sharp or flat at the 12 fret?

A lot of JS Basses have neck dive problems (mine did, I got it reset) and the action is to high to really crank it down to where it needs to be.

If you want to show some pics, get a free account at photobucket.com,
load your pics there and send 'em over to this thread here at LTG.

If you use the search function here, you can probably find out how to do it exactly by searching under photobucket or photobucket.com.

Good luck!
 

swamp2

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gilded said:
swamp,

What is your action height? Why don't you measure it at the 12th fret, by giving us the space between the 12th fret and the bottom of the strings?
In 64ths, yet.

Also, are your strings old, really old, or new??

Are the strings sharp or flat at the 12 fret?

A lot of JS Basses have neck dive problems (mine did, I got it reset) and the action is to high to really crank it down to where it needs to be.

If you want to show some pics, get a free account at photobucket.com,
load your pics there and send 'em over to this thread here at LTG.

If you use the search function here, you can probably find out how to do it exactly by searching under photobucket or photobucket.com.

Good luck!
Ok, the action from the top of the 12th fret to the bottom of the E string is somewhere around 0.085". Brand new stirngs. It's a hair sharp at the 12th fret. I'd like to get the action lower, but that's about all it can take w/out obnoxious buzz. Not sure what you mean by neck dive? I've adjust most of the relief out of the neck, the truss rod is still fine.
 

swamp2

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Ok, here's my attempt at sticking up a photo...

If it works - the bridge adjusting screw is right between the D and G strings - those saddles can't move back. I probably only need 1/8", but I can't get it...


bridge.jpg
 

fronobulax

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Yep, we've firmly established that you have a problem and it is not one that I have with essentially the same bridge. I'm not a luthier, nor do I play one on television, but in the absence of a manufacturing problem (i.e. bridge placed incorrectly) the other factors that effect string length would seem to be the nut, the neck and the action. Even though I possess a genuine Guild truss rod adjustment tool (aka "nut driver" with "Guild" on the handle) I've never been comfortable messing with the neck so I will defer to your experience when you say the neck is properly adjusted. So if my mental model of movements is correct, raising the bridge plate or increasing the depth at the nut should buy you some wiggle room at the bridge saddle. I'd try the former because it can be easily undone.

In the absence of better advice, this weekend (since I will be "away from base/bass" for a couple of days) I will a) confirm that I am happy with the intonation on my JS II and b) take some of the measurements that might indicate what is different.

On the other hand, the nice thing about playing a thump machine is that no one, including you, knows whether you really played the right note/pitch or not so it may be the case that there is only so close you can get with a JS.
 

The Guilds of Grot

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fronobulax said:
Even though I possess a genuine Guild truss rod adjustment tool (aka "nut driver" with "Guild" on the handle)
Since ya ain't usin' it ya wouldn't be interested in sellin' that would ya?
 

gilded

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What's neck dive?

That's when the 'neck to body angle' is too shallow and the neck appears to 'dive' into the body. Happens a lot with Guild JS basses (Gibson SG-type basses, too).

Think of the fingerboard as a 'straight line' (forget about the relief, just sight down the neck; pretend it's straight). Follow the plane of this 'straight line' and see where it eventually intersects with some point on the top of the bass.

If the 'straight line' hits the bottom of the bridge, or lands in front of the bridge, your 'neck set' either has a very shallow angle or your neck has moved/warped/twisted over the last 30 years and, again', 'dived' into the body.

What are the symptoms of a shallow neck set? Well, the symptoms are what I see in your pic; bridge set absolutely flat, as low as it can go.

As well, your string height is fairly low. By way of example, my Starfire Bass has an action height of 7/64ths at the 12th fret, compared to your .085". I can't give you the height on my JS, because I haven't measured it and won't until I change the strings. Besides, it's fretless.

The low action, shallow neck angle and screw position on your bass, taken as a whole, make for slightly sharp intonation. If you raise your bridge height, the geometry of the bridge is such that the saddles will gradually move away from the 12th fret. As you raise the strings, at some point, your bass will be in tune. You may or may not like the string height or feel, but it will be in tune.......

That's my 2 cents, swamp. Food for thought, anyway.
 

swamp2

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gilded said:
What's neck dive?

That's when the 'neck to body angle' is too shallow and the neck appears to 'dive' into the body. Happens a lot with Guild JS basses (Gibson SG-type basses, too).

Think of the fingerboard as a 'straight line' (forget about the relief, just sight down the neck; pretend it's straight). Follow the plane of this 'straight line' and see where it eventually intersects with some point on the top of the bass.

If the 'straight line' hits the bottom of the bridge, or lands in front of the bridge, your 'neck set' either has a very shallow angle or your neck has moved/warped/twisted over the last 30 years and, again', 'dived' into the body.

What are the symptoms of a shallow neck set? Well, the symptoms are what I see in your pic; bridge set absolutely flat, as low as it can go.

As well, your string height is fairly low. By way of example, my Starfire Bass has an action height of 7/64ths at the 12th fret, compared to your .085". I can't give you the height on my JS, because I haven't measured it and won't until I change the strings. Besides, it's fretless.

The low action, shallow neck angle and screw position on your bass, taken as a whole, make for slightly sharp intonation. If you raise your bridge height, the geometry of the bridge is such that the saddles will gradually move away from the 12th fret. As you raise the strings, at some point, your bass will be in tune. You may or may not like the string height or feel, but it will be in tune.......

That's my 2 cents, swamp. Food for thought, anyway.

Well... I guess I could have a mild case of neck dive. I don't consider it bad enough for a reset, the intonation problem isn't that severe. The action is already higher than I'd like, though. About 6 months ago I picked up a new SG Supreme and am able to run a very low action on that - the contrast between my JS and the SG is not insignficant. It pains me that it might also fall prey to the same issue, although given that the JS is 35 years old - 35 years from now I probably won't give much of a crap that the SG has a little intonation trouble.

Why do these particular models have a tendency to have neck dive? Is it a good idea to keep them in a lower state of tune?

But when all is said and done, it's the design of the bridge that's frustrating. The slots are there for the saddle to move, but it can't be done. Bad Designer! Bad!!!
 

gilded

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swamp2 said:
Well... I guess I could have a mild case of neck dive. I don't consider it bad enough for a reset, the intonation problem isn't that severe. The action is already higher than I'd like, though. About 6 months ago I picked up a new SG Supreme and am able to run a very low action on that - the contrast between my JS and the SG is not insignficant. It pains me that it might also fall prey to the same issue, although given that the JS is 35 years old - 35 years from now I probably won't give much of a crap that the SG has a little intonation trouble.

Why do these particular models have a tendency to have neck dive? Is it a good idea to keep them in a lower state of tune?

But when all is said and done, it's the design of the bridge that's frustrating. The slots are there for the saddle to move, but it can't be done. Bad Designer! Bad!!!

Swamp, 'neck dive' happens in the best of families. :roll:

But, 'why gilded, why?' I would think JS bass necks have a tendency to 'dive' because:
a) the factory missed the neck set in the first place,
b) the join between neck and body joint is relatively insubstantial compared to the several hundred foot-pounds of pressure exerted on the bass over the years by string tension.

Also, the join can be just fine, but the neck can 'pull up' over time because:
c) the wood is 'green',
d) the instrument gets hot, which limbers the wood up and the string pressure pulls it up, etc.
e) none of the above. Ask a real repairman, like Hans.

Hey, I just looked at one of my Guild Bass bridges. I have a clever plan.....

If your bridge is truly flat against the metal piece under the bridge, get a set of allen wrenches and unscrew the offending height adjustment screw, 'right on out of there'. That way, you can move the wooden saddles back an incremental amount, say about 30 or 40% of the width of the height screw (which is .15 or .16" wide), until the metal sliders cant go any further back.

[Oh, I think the string pressure will keep the bridge in place]

If that's not enough movement, then take the bridge off, pop the wooden saddles off (on the appropriate strings), unscrew the metal sliders that hold the wooden saddles in place and turn them 180 degrees (it'll work, honest), which will put the slider tightening-screw in front of the saddle(s). Then, you'll have plenty of movement, so much so that you may even be able to put the height adjustment screw back in (which will make us all feel better!).

You can also move/wiggle all of wooden saddles 'sideways', which will allow you to get around the height adjustment screw-issue, but since your saddles have deep grooves in them, your string spacing will be out of whack.

Before you do all this, make sure that you are working someplace where the carpet/floor is a lot lighter than the brown wooden saddles. The saddles fall off easily, especially once you remove them. I just spent five minutes looking for one! Be careful!!

That's all I can come up with. Good luck.
 

danerectal

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gilded said:
If that's not enough movement, then take the bridge off, pop the wooden saddles off (on the appropriate strings), unscrew the metal sliders that hold the wooden saddles in place and turn them 180 degrees (it'll work, honest), which will put the slider tightening-screw in front of the saddle(s). Then, you'll have plenty of movement, so much so that you may even be able to put the height adjustment screw back in (which will make us all feel better!).

swamp2 said:
Ok, here's my attempt at sticking up a photo...

If it works - the bridge adjusting screw is right between the D and G strings - those saddles can't move back. I probably only need 1/8", but I can't get it...


bridge.jpg

Judging by the picture, the sliders aren't really the problem. It looks like the acutal wood saddle is right up against the height screw for the bridge.

gilded said:
If your bridge is truly flat against the metal piece under the bridge, get a set of allen wrenches and unscrew the offending height adjustment screw, 'right on out of there'. That way, you can move the wooden saddles back an incremental amount, say about 30 or 40% of the width of the height screw (which is .15 or .16" wide), until the metal sliders cant go any further back.

[...]

You can also move/wiggle all of wooden saddles 'sideways', which will allow you to get around the height adjustment screw-issue, but since your saddles have deep grooves in them, your string spacing will be out of whack.

This is probably a better tail to chase in this situation, though it's not my pick on how to fix the issue. If you could get a new saddle made (so as not to destroy the original one) and give it a notch to accomodate the hight screw, you'll probably able to get the movement you so desire.
 

swamp2

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gilded said:
Swamp, 'neck dive' happens in the best of families. :roll:

But, 'why gilded, why?' I would think JS bass necks have a tendency to 'dive' because:
a) the factory missed the neck set in the first place,
b) the join between neck and body joint is relatively insubstantial compared to the several hundred foot-pounds of pressure exerted on the bass over the years by string tension.

Also, the join can be just fine, but the neck can 'pull up' over time because:
c) the wood is 'green',
d) the instrument gets hot, which limbers the wood up and the string pressure pulls it up, etc.
e) none of the above. Ask a real repairman, like Hans.

Hey, I just looked at one of my Guild Bass bridges. I have a clever plan.....

If your bridge is truly flat against the metal piece under the bridge, get a set of allen wrenches and unscrew the offending height adjustment screw, 'right on out of there'. That way, you can move the wooden saddles back an incremental amount, say about 30 or 40% of the width of the height screw (which is .15 or .16" wide), until the metal sliders cant go any further back.

[Oh, I think the string pressure will keep the bridge in place]

If that's not enough movement, then take the bridge off, pop the wooden saddles off (on the appropriate strings), unscrew the metal sliders that hold the wooden saddles in place and turn them 180 degrees (it'll work, honest), which will put the slider tightening-screw in front of the saddle(s). Then, you'll have plenty of movement, so much so that you may even be able to put the height adjustment screw back in (which will make us all feel better!).

Actually, I had tried removing the offending height adjusting screw. On the bass side, I actually don't have it all the way to the bottom - so since the bridge wasn't sitting completely flush against the backing plate, the bridge would actually vibrate very iaudibly and rritatingly with no screw/no tension there. I was able to move the saddle back, of course - total movement needed was probably 1/8" or less - and intonation was fine, but the cure was more annoying than the disease. The screw went back in.

Thanks for the thoughts, I appreciate the inputs!
 

swamp2

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danerectal said:
This is probably a better tail to chase in this situation, though it's not my pick on how to fix the issue. If you could get a new saddle made (so as not to destroy the original one) and give it a notch to accomodate the hight screw, you'll probably able to get the movement you so desire.

Hey Dane, what would be your pick on how to fix it? I may try making up a narrower saddle as you suggest, I imagine that would do the trick...
 

danerectal

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I would say that making a new saddle that has clearance around the height screw is your best option. If I had the bass in front of me, it would be easier to say exactly what my plan of action would be. I think the easiest fix is the new saddle.
 
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