String or tuner slipping in cold weather

[violmando]

This may have been discussed before, but I couldn't find the right terms to find any threads.....

I have a Larson/Stahl mandocello from the 20s with the original tuners; they have always worked fine for me until this past week. First, the other night at rehearsal, one of the G strings kept going flat and I had to constantly retune, until I had been inside for about 45 min., I'd say.
Tonight, my quartet had a gig and the same thing happened with my outside A string, even MORE drastically, and this time it lasted almost an hour before finally settling to pitch; it would go out during the tune, I'd tune between each piece. And I wasn't playing much on the As at all. (It would go as low as G#)
Temperature here in Ohio is low 40s, high 30s at this time. At home, practicing, of course, it stays almost perfectly in tune. The only tuning peg that has ever given me any trouble is the upper D and I've always thought it's because I use a soft case and it gets more wear taking the case on and off.

Strings are Thomastik-Insfeld, less than 2months old. I've used them most of the time w/o problems. Any suggestions? REALLY frustrated about this one. Of course, I will try to arrive at places sooner, but there is a limit to how quickly I can get there sometimes, you know?
Yvonne, member of the Dayton Mandolin Orchestra & Odyssey Mandolin Quartet

[allenhopkins]

OK, what makes a string go flat? Obviously, the tension of the string is lowered, possibly due to:
1. Slippage of a tuning peg
2. Bending of a tailpiece hook
3. Distortion of the tailpiece
4. Sinking of the top arch
5. Stretching out of the core or winding of the string itself
6. Lowering of the bridge saddle

And there may be more, but those are what comes immediately to mind. If only one string is affected at a time -- i.e., all the strings don't go flat at once -- it's probably not anything affecting the geometry of the instrument's body, or the entire tailpiece or the bridge. Problems there would affect all the strings, not just one.

I'd check to make sure that strings aren't hanging up in the nut or bridge slots, that the tuners aren't slipping -- tune a string to pitch, then take it between your fingers and give it a yank, and see if the pitch goes down. I'd check the tailpiece to make sure that the string loops are firmly seated on the string hooks, and that none of the string hooks is bending.

Temperature changes could be involved, but chances are those would affect all the strings, perhaps not equally, but perceptibly. If your 'cello's at 40º, and warms up to room temperature, chances are that it will go sharp, and that you'll find this affecting all the strings, not just one.

Alternatively, of course, you could have a bad string, and one of the first "quick fix" strategies is to replace one or both of the problem strings. With a mandocello, that's not so cheap, but defective strings are always a plausible culprit.

Good luck! And, of course, having a repair person look the instrument over never hurts.

[violmando]

Thanks, Allen. I'm going with number 1 or 2. When it first happened, I thought it was the particular string and I DO have single replacements for some of them, since I also own a bass domra which I strung with single TI mandocello strings and I also have a set of LaBella mc strings. But I'm pretty sure it's something to do with the tuners....I have 2 gigs this weekend to get through and then if it's still going crazy, it's off to Mark Kaiser at Fretworks to see what's wrong. I'm just afraid it won't act up for him, like it doesn't act up at home! Yvonne

[Big Joe]

It could be the nut is needing some attention as well. Sometimes they can get dirty in the slots or the strings can bind a bit and cause it to not tune well. The same with the saddle slots. If you have never had an issue with this instrument before it could be that....or the strings just need to be replaced. Tuners are usually about the last thing to be the problem, though if they have adjustment screws they can be tightened a bit and that may help. However, it is likely one of the above more than the tuners themselves.

[man dough nollij]

I've seen it posted here on the Cafe that it is impossible for string tension to cause the tuners to slip, just by nature of the worm gear. From a mechanical perspective, that makes sense. It would be interesting to do an experiment to see if typical worm gear tuners can ever be turned backwards by string tension. :confused:

[violmando]

This morning, while checking out/tuning/practicing before the gig this afternoon, I found the problem. I had been rigorously checking everything since this problem started, but I guess this was in flux...The bottom seam is now unglued, very close to the tailpiece, a place it had been when I got the instrument 3 or so years ago. I bet that's what's been bugging it; it wasn't open the other night nor yesterday am when I practiced, but it was coming open and that was the problem, I guess. Oh well....two more days and then the repair shop. I am lucky enough that my pal down the street owns one almost identical. (Somewhere here on the Cafe there's a pic of our Larsons together). THANKS for the help! Yvonne

[allenhopkins]

So in fact the tailpiece was creeping toward the bridge, as the bottom seam let go? Still don't understand why this wouldn't affect all the strings, since the lowering of tension as the tailpiece moved, should have been distributed across all eight...

In any case, hope the fix is complete and reasonably priced!

[violmando]

Really don't know, but once the seam came open, I had my normal intonation problems...It just went slightly flat here and there as I played at the two gigs. And I'm talking teeny amounts that bug only me.....It was a BIG relief. Having a friend with a "twin" is a REAL BONUS so I can still practice and qtet can rehearse while it's in the shop, too. THANKS for the advice, Allen. Yvonne