Can't fix back bow with truss rod.

[Nlelith]

Ok, so my Carvin DC700 neck developed a back bow. When I press 1st string against 1st/24th frets, there is no gap between it and the frets, and when I press 7th string against 1st/24th frets, there is veeery little gap. This is not normal. Treble strings buzz like crazy on the first few frets, really annoying. Truss rod is all the way counter-clockwise, it won't move any further.

I already had this problem with this very DC700 around in Feb 2014, and couldn't do any significant adjustment to the neck, until one day it fixed itself... Now this problem is back, but in a completely different weather season, and once again, I can't do much about it. I live in an apartment, and store this guitar in the same environment throughout the year. Why is this even happening (considering that Carvin guitars have 2-way truss rods, and this should be easy fixable), and what should I do about it? Wait for the day it fixes itself, again?

Note: we don't have any guitar techs that can do luthier tier stuff around here, only minor setup...

 

[FifthCircleSquared]

Are you actually measuring relief with some feeler guages?

The reason I ask is that I've had similar trouble with a CS624, even though the neck was just about straight as an arrow. Turns out that I need a new nut, as the orignial was cut about as low as possible, and then I went and put 12-60's on it before going back to 10's, which widened the slots and lowered them just that little bit where it went from awesome to rattle city.

To test:

Fret or Capo at third fret. Pluck behind the string. Does it ping like behind the nut at the headstock? If so, good. If the string is dead, the nut slot for that string is too deep.

Hope this helps.

 

[jerm]

Have you contacted anyone at Carvin? What'd they say?

 

[Nlelith]

UlonProg, not with the feeler gauges, but I do this "fret string at 1st/last fret" pretty often, so I can tell that relief got bad, not what it used to be.

Nut slots on my DC700 are about as low as possible as well, and I did use .11 sets before (been a while, though), using .10 strings now. I know about this "fret at the 3rd fret" method as well, and it was the first thing that I checked when noticed the buzz, slots are fine. Also, it wouldn't fix itself last time if this was the case. However, I guess that getting new nut with slots not as deep could potentially fix the problem, right? I'll keep this in mind... Edit: just realized it won't fix the buzz on the first frets.

jerm, I did contact Chris when I had this problem last year. He said he'll forward my mail to their tech and I never got an reply since then, but that was about the time when neck fixed itself... Just checked my gmail, and noticed that it was in the middle of June! Hmmm, so last year it started in February, and lasted till summer. And this year problem re-occurred a little later. I'll email Chris about this, and hope this time I'll get some advice on what should I do.

 

[FifthCircleSquared]

Just one more quick thing to try:

Does your DC700 have the tune-o-matic bridge? If so, maybe the posts are screwed down a little bit more than usual. They turn VERY easily when changing strings, etc, and I recently had to turn mine up almost TWO full turns to get the action back to 1/16" at the 12th fret.

 

[Nlelith]

^ Nope, bridge is Floyd Rose.

 

[FifthCircleSquared]

Hmm, I don't know what to tell you man. I'd still check the action on the guitar, although it is quite a bit more involved to make changes with a Floyd bridge. There are some good resources around here for setting trems.

I understand there may not be very many good techs around where you are, but are there any really experience musicians? Maybe you could put your heads together.

 

[Alexander_Wiebe]

Its really hard to explain how to fix the truss rod, just go to a music shop and invest the money and ask the person if he/she can show you how to fix the truss rod