Mando help

[Jim Kirkland]

I have been playing for a few years, rebuilt a crushed oval hole 1930 regal, built an archtop octave mando, and do violin repair as a hobby. My MK evolution has a slight sinking top at the clef f hole near the tone bar. Appears to be stable at the moment. Have a hard time keeping in tune, and after taking mando out of the case, at times, there is a loud pop from the body. I have looked inside, and pushed on both tone bars, appears not to be loose or broken. Have checked the tuners for loose screws, all adjusted and tight. Checked the bridge and saddle for fitness and burs, all appear well. Nut is not binding. This mando has an allen tailpiece, mammoth ivory insert in saddle, tusq nut, and an ebony armrest. I am lookin for help as to what could be the issue, other than a pac rim mando. It doesn't bother me to take the back off and do what is necessary. If you have any ideas I would greatly appreciate them

[Michael Lewis]

Do a more thorough inspection of the braces. I think you may find at least one end coming loose. It is not easy to see inside when you have F holes, but keep trying until you can see the entire length of each brace. A dental mirror and lots of light.

[nelson_luthier]

How tightly does the mando fit in it's case? Could be that when you close the cover you are depressing the top causing it to "pop" inward? When you pull it out of the case it may be simply popping back due to the release of pressure. If that's the case you just need a bigger case!

This could also account for the sinking top.

Greg N

[Jim Kirkland]

Thanks Greg, checked the case, fits well, not tight, is the orginal oblong. Michael, I will take a close look tomorrow at the bracing. The sink in the top is just to the high upper side of the clef tone bar, about 2 inches in front and 2 inches behind the bridge. We are very dry here in Las Cruces, NM, and the sink didn't occur until we had a real wet spell. I do keep a humidifier in the case. I will keep you posted as to the outcome. Thank you Jim Kirkland

[Bill Snyder]

What is a clef tone bar? I am not trying to be a smart alec but there is a bass clef and a treble clef (and actually quite a few more clefs) so I am in the dark as to which of the two tone bars would be the clef side. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/rock.gif

[Paul Hostetter]

Clef (never cleff) is not an operative term for mandolin morphology. It literally means key, and can refer to bass clef, treble, clef, alto clef, and so on. Music terminology. Perhaps Deserto was referring to an f-hole which vaguely resembles a treble clef sign? But which one? Does it matter if one of them is sinking?

http://www.ucolick.org/~sla/abcmusic/clef.gif

[Jim Kirkland]

Bill sorry, should of included bass cleff. I am rechecking the saddle and nut to make sure they are not binding. I left mando out of case last night and picked it up this morning and played for approx 15 min, did not tune or make any adjustments, and the pop noise came again. I have repaired a lot of string instruments and rebuilt, about 50 violins, 4 mandos, 8 guitars, and 3 upright bass, and built a baby archtop, cut away guitar body, which I put tone bars in instead of braces, a 20 inch scale neck, tune one octave below a mando, and play like a mando. This problem sure has me scratching my head. I will run the files thru the nut and saddle slots and check for burrs. If that doesn't work for the pop sound, I will take the allen tailpiece and ivory saddle off, one at a time, and listen for the pop. If that fails, the back is comming off. Sure hate to break the finish, but this is a learning process, and I feel there is a fix. I do believe there is a much better mando there, and I am out to find it. This is a MK evolution, and not a bad sounding mando. Well enough for now, you can hear my fustration. Please give me ideas for a fix. Thank you. Jim

[Bill Snyder]

Paul you forgot a few. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif
http://www.johnmcgann.com/clefimages/clefs.jpg
Image from John McGann's website.

[Jim Kirkland]

Got the pop sound fixed. I was going thru a setup and I noticed that the bridge adjustment wheel on the bottom side, E string, had no pressure on it and was loose. Raised it enough to put slight pressure on the wheel, and the pop went away. As to the sink in the top, I got a lot of light inside and did a lot of looking, cannot see anything loose or broken. Did notice that the tone bar on the bass side, G string, was not as smooth and appeared not to be as thick as the the tone bar. I am going to leave it alone for now and after I purchase another mando, I will take this one apart and rebuild it. Thanks for the info. Jim

[bryce]

Have you tried leaving the strings loosened over night to see if the top comes back up at the F hole. I built an experimental mandolin years ago that sagged a little on the bridge sides (inside) of both F holes(so I thought). looking at them later from the tailpiece end I determined that the outside edges of the F hole had in fact risen slightly. Probably slight pull upward from the tailend. It hasn't moved in 5 years. Tremendous sounding mandolin. Probably just built a shade thin. I have reglued a MK tonebar that had let the top sag, but with a light and mirror it was very obvious. Try loosening the strings for a day or two. David