#1
Hi,

I bought a used Yamaha C-150 and notice that the neck is somewhat not straight and here's some pics:







And here Photo I found on the internet:



The 12nd frets sound normal but the high E string always need to retune because it out of tune frequently.
I haven't change the string yet. Everything untouched.

Sorry, English is not my first language.
#2
The neck should have a slight concave bend. This is to stop strings rattling when you pluck them. The concave bend in a classical guitar is greater than an acoustic guitar because nylon strings vibrate more than steel strings.

From the photo it looks as if the action needs adjusting - this is the height of the strings above the fretboard measured at the 12 fret. If the action is too high the guitar will be more difficult to play. The action is adjusted by lowering the saddle of the bridge - it is not a difficult job but if you are not sure it's best to have it done by a technician.

Look here for info and instructions:

http://www.frets.com/FretsPages/Musician/Guitar/Setup/LowerAction/loweraction01.html
#3
Thank, for reply. I'm sure I can do it myself since I used to take off Guitar neck before (I made a thread about this before and people was like "WTF").

Anyway, will change the new string affect the sound? This string I'm using is somewhat sound really good but one of the string goes out of tune and I need to replace it. The high E string sound really good that, my friend, I can't really describe it to you. And Wounded Nylon vs Steel wounded, Which one will sound better in term of multiple genre?
#4
Quote by sosxradar
Thank, for reply. I'm sure I can do it myself since I used to take off Guitar neck before (I made a thread about this before and people was like "WTF").

Anyway, will change the new string affect the sound? This string I'm using is somewhat sound really good but one of the string goes out of tune and I need to replace it. The high E string sound really good that, my friend, I can't really describe it to you. And Wounded Nylon vs Steel wounded, Which one will sound better in term of multiple genre?


I would recommend that you replace all of the strings with a new set of nylon strings.

It is very important that you use nylon strings and not steel strings which have a much higher tension than nylon ones and would damage the classical guitar. There is a short explanation about classical guitar strings here: https://en.wikipedia.org/wiki/Classical_guitar_strings.

Classical guitar strings are available in different tensions: normal (or soft) tension, medium tension and high (or hard) tension. Any of these would be fine on your guitar - generally the lower tension strings are more mellow and slightly easier to play and the high tension strings are brighter sounding but stiffer so a little harder to play. It's worth trying different makes and tensions to see which you prefer - there are many websites online where you can but strings.

Some more information here: https://www.stringsbymail.com/pages/classical-guitar-string-basics-19.html
#5
I finally found the problem of this guitar. It doesn't have the Saddle. The seller look anxious (if i remember correctly) when I inspect the guitar and I still mess it up. There's no way to adjust the action. I'm pretty sure that he bought this at lower price than fix it and sell it!!!

Can I adjust the intonation? You mention that the classical guitar is slight concave bend and if it does then I don't know why the action is so high. I can't find any Eye point view of classical guitar on the internet at all. Can I have your image of your classical guitar from top view? So, I can get the idea of how the neck work.

EDIT: I measure the 12nd frets and it meet the set up of 4mm on the first string and 3mm at the sixth string.

I also discover why the first E string produce cool sound different from other guitar I've play is because it doesn't has saddle and the string didn't lay on anything so the sound just go off when pluck and then it's produce some cool effect because it has no rest on the saddle. Cool advantage, though!
Last edited by sosxradar at Oct 1, 2016,
#6
I'm no expert on nylon string action, but from what I've seen, the line of the fret tops generally points lower on the bridge than it does on a correctly-set steel string. On a steel string, the frets will ideally point at or very near the top the wood part of the bridge, if you imagine the neck to be straight. I personally would not want a nylon string where the fret line pointed more than halfway down the wood part of the bridge, again assuming that the neck is straight.
#7
Quote by sosxradar
I finally found the problem of this guitar. It doesn't have the Saddle. The seller look anxious (if i remember correctly) when I inspect the guitar and I still mess it up. There's no way to adjust the action. I'm pretty sure that he bought this at lower price than fix it and sell it!!!

Can I adjust the intonation? You mention that the classical guitar is slight concave bend and if it does then I don't know why the action is so high. I can't find any Eye point view of classical guitar on the internet at all. Can I have your image of your classical guitar from top view? So, I can get the idea of how the neck work.

EDIT: I measure the 12nd frets and it meet the set up of 4mm on the first string and 3mm at the sixth string.

I also discover why the first E string produce cool sound different from other guitar I've play is because it doesn't has saddle and the string didn't lay on anything so the sound just go off when pluck and then it's produce some cool effect because it has no rest on the saddle. Cool advantage, though!


OK. Here is a photo of the bridge of my oldest classical guitar:



You can see the white saddle in the slot of the the bridge. The saddle is slightly higher on the bass string side - this is normal because the bass strings vibrate with a larger amplitude than the treble strings. On my guitar the action at the 12th fret is 4mm for the 6th string and 3mm for the 1st string. This is about right for a classical guitar.

I suspect that the saddle has been removed from your guitar to get a better action because the guitar top has risen at the bridge. This happens as guitars age because of the tension of the strings. This has happened on my guitar which is nearly 50 years old - you can see that the angle of the strings where they cross the saddle (called the break angle) is quite shallow - I keep the strings tuned down two semitones to reduce the tension. The next step when the guitar is a little older will be to use ball-end nylon strings to achieve a better break angle. It might help if you use ball-end strings on your guitar. You can buy a saddle at most music stores or make one from a piece of plastic. You can see from the photo that my saddle is only a little bit higher than the bridge - this is to get a good action - it works OK.
#8
If you are DIY-minded, and the guitar doesn't have a truss rod, you can try something like this to set the neck at a higher angle:



This is my old requinto, which was falling apart when I rescued it from my brother-in-law. I cut a wide slot down the heel, then bent the neck back with the guitar face-down on two blocks and weighted with a bucket of water. The joint was filled with slow-setting epoxy, then tidied up with a black faux ebony bog made from epoxy and black powder paint. It is wider then need be because I mucked it up the first time, and had to redo it.
#9
Maybe I don't need to adjust the neck it all because it seem that it's meet the standard. The real problem is the top at the bridge has risen and that why saddle need to remove. I'm using the ball end because otherwise it will has no break angle.

So, My final question is, How long will my guitar last according to your experience with saddle removed? If I'm not correct, my guitar might be about 40 years old.
#10
Quote by sosxradar
Maybe I don't need to adjust the neck it all because it seem that it's meet the standard. The real problem is the top at the bridge has risen and that why saddle need to remove. I'm using the ball end because otherwise it will has no break angle.

So, My final question is, How long will my guitar last according to your experience with saddle removed? If I'm not correct, my guitar might be about 40 years old.


My guitar is almost 50 so with a bit of luck if your guitar is 40 years old you have at least 10 years to enjoy playing it
#11
Oh and sosxradar - I would recommend that you do fit a saddle even if it is only very slightly higher than the saddle slot. Two reasons: 1st the scale length will be slightly less than it should be without a saddle so that may effect the intonation; 2nd the strings - especially the bass ones - will wear down the wood of the bridge over time.
#12
The neck looks good, the bridge has maybe pulled up a little from too high tuning or someone put a set of steel strings on it or a loose brace inside somewhere. Sand down the bridge a little in front of the saddle to provide clearance for the strings. You need a saddle for lots of reasons, tone, sustain and intonation.