Neck Reset for Sigma?

[Jeremy Steele]

I recently picked up a 20 year old Sigma DR-28 at a yard sale for a very good price. I love the way it sounds (all it seems to lack is a pronounced bottom end) but it needs a neck reset. Are these guitars constructed in a way which would make a neck reset possible? If so, is it worth doing? or should I just tune down a half step and capo the first fret, which is what I'm doing now. Opinions appreciated.

[Antonio Cotichini]

Why does it need a neck reset? What's the problem? Maybe it just needs a truss rod adjustment or a new nut and saddle.
Also if it needs a re-fretting, with consequent fretboard sanding, it worth the expense. You'll have a nice work-horse.
Antonio

[Jeremy Steele]

I performed the test I saw on Frets.com whereby Frank places a straightedge on the frets, and if the end hits the bridge at too low a spot, a reset is called for. The saddle is as low as it can possibly be, and from what I can see a truss rod adjustment will only result in a backbowed neck. Don't most guitars need a neck reset when they get to be 20-25 years old?

[Antonio Cotichini]

Well, when a guitar is old it does need a check for sure, but not necessarily a neck reset. Just if it needs it.
In the case of your Sigma, if the straight edge test was properly done, you have to verify the amount of that low spot and then decide if is possible to correct the gap just planing a bit the fretboard in the direction of the headstock, which is still a convenient solution, or take away the neck and change the angle, which is expensive. But if you love that axe...
Anyway, did you check also the bridge area? Does it belly? Is it inclined toward the sound hole? And are the frets well aligned? The value of an old Sigma is less than the cost of the job.
The decision is yours, Jeremy.
Good luck
Antonio

[Magnus Hultin]

Based on Your measurement it seems like You need a neck reset. These sigmas are full laminate and often grow a belly behind the bridge. On such a guitar I would be prepared to test a bridgedoctor. Chance is that the rotation back to original position of the bridge actually results in that the bridge top ends up lower than it is now, and You may not need a neck reset after all.

Anyway, Sigmas normally have dovetail joints. If the trussrodd access is below a plastic cover in the head, You probably need to loosen it befor removing teh neck. I had such a Sigma (from the 70:s) and the trussrod anchor hooked onto a cavity in the neckblock and came up with the neck. If not loosened, risk is that it tears some wood from the neckblock as it comes up. If the trussrod is adjusted from the soundhole this will be no issue.

Magnus

[Antonio Cotichini]

Bridge Doctor strikes again!!

[Ned Knepp]

I've got an early/mid '70 Sigma that has a belly but the bridge didn't rotate. What I've found is that the long legs of the X brace is starting to roll on the outside edge, causing the inside edge to separate from the top. It's a bit like the brace is twisting one direction while the face is pulling in another. I haven't tried a bridge doctor because I can't see how it would help.

I can't see any way short of removing the back to fix my problem.

Ned

[Magnus Hultin]

The one I have is an early 70:s with "greek-sigma" on the headstock, model GCR-7, which was an OM size.
This one, just as an 80:s Sigma I also have, has an adjustable type of bridge, allowing height-adjustment in each side of the saddlebone. I have never cared particularly for these solutions and am thinking of modifying the bridges for standard fixed saddlebones.

I cant say I have examined the inside of the top carefully, but I have studied the bottomside of the bridge, which has a bolt through the top behind the stringpins. I think I would have noticed if any braces were loose. I have assumed that these laminated tops haven´t been stong enough to withstand the forces pulling upp behind the bridge. I have seen many many similar Greek-Sigmas in this condition.

I have thought of usingthe existing bolt in the bridge to fasten a bridgedoctor type of device.

On my GCR-7 the bridge has tilted forward significantly and one result is a belly between the rear legs of the X. I think the belly starts already in front of the bridge, why I think a bridgedoctor may actually lower the entire bridge.

Magnus