Wacko G strings

[Steve Martin]

These mandolins be wicked little beasts sometimes. Here’s my problem. Just put a new set of strings on my ‘94 Flatiron F5. Some sour sounds are coming from the G (4th) strings. Basically, when I tune both strings to the same frequency, the top string goes sharp as I move up the fretboard. The biggest difference between the two strings is around the 5th fret. As I move further up, the difference in pitch decreases so that by the time I reach the 12th fret, the frequencies are roughly the same. I didn’t notice this problem before I changed the strings. I checked both the nut and the saddle, and the strings appear to be seated properly in their respective grooves. Anybody have any ideas about what is going on?

[George R. Lane]

Steve,
I find that same problem with my Yellowstone. I usually bring them up to tune and then I lift the strings to stretch them. I do this a couple of times and that usually solves that problem. Hope this helps.

[Mandobart]

I'm thinking the nut slot on the wacky string is either binding or too shallow. Have you recently changed string brand or gage? I use Big Bends Nut Sauce in the nut slots on every string change.

[Nevin]

I'm thinking the nut slot on the wacky string is either binding or too shallow. Have you recently changed string brand or gage? I use Big Bends Nut Sauce in the nut slots on every string change.

If the nut were to shallow, would't the pitch difference be most pronounced at the first fret, and decrease as you go up the neck?

[gtani7]

1. they could be defective strings, bad core or windings: http://www.mandolincafe.com/forum/sh...string-problem

http://www.mandolincafe.com/forum/sh...tive-or-go-bad

2. graphite in saddle slots, Teflon lube in nut slots. Does it ping in either slot, do the D or G saddle slots have imprints of the string windings in them?

3. Stretch strings gently by tuning a half step over, then tune back down

[Steve Martin]

Thanks for the input. They are new strings, DR MD-11s. I've added a little pencil lead (graphite) to the nut & tried stretching the strings to no avail. Perhaps it is a bad string, but the physics make no sense.

[Larry Simonson]

Since fretting a note requires stretching the string to greater tension, thereby sharpening the note, it seems reasonable to reduce the string height as much as possible while maintaining buzz free good tone and volume. This sharpening on fretting is, in my experience, most pronounced on the lowest frets and at a minimum at the 12th fret and exacerbated by high nuts and actions. I wonder if fret boards are or could be made to compensate somewhat for this problem.

[Willie Poole]

I had the same problem but on the A string only, after trying different strings to no avail I swapped out the bridge saddle and it cured the problem although the slots in the nut and bridge saddle appeared to be OK, I would swap the G strings around with each other and if the same string did it then I would change that string....There have been posts about strings not being the same diameter through out the length of the string, defective strings do happen every now and them...I`m sure DR would like to hear about it if it is a defective string....

Willie

[Mandobart]

If the nut were to shallow, would't the pitch difference be most pronounced at the first fret, and decrease as you go up the neck?

Yes. If the nut slot is too shallow, the string stretches more to contact the lower frets, making it sharp. As you move higher up the fretboard the effect is less. When intonation is off on the lower frets but ok oh higher frets IME it is nut slots.

[ProfChris]

Capo your mandolin at a low fret (1-3 probably), tune the strings to unison, and see if the problem is still there. If so it's almost certainly a defective string, probably it's a little thin in one spot (this means that the mass of the string between saddle and where you are fretting is different between strings, so they ring out different sounds).

If the problem goes away when you capo and retune, then it must be at the nut.

[amowry]

It sounds like the nut slots may be too high, and you may also have too much relief in the fretboard. If adjusting these doesn't help you could have someone make you a compensated nut, which at the very least could distribute the pitch shift more evenly across the lower frets, so it's not so pronounced at the fifth.

[Steve Martin]

I swapped the strings earlier today, and the intonation problem stayed with the string, so I'm pretty certain it's a defective string. I emailed DR Strings and they responded promptly and asked for my address so they could send me new G strings. Later today I removed the offending string and replaced it with a new one. Voila, no intonation problem. Been changing strings for well nigh 50 years and never encountered this before. Thanks for all the input.

[amowry]

Ah, I missed that it was just one string! Yes, I've had a few defective strings, even a few that had their own internal buzzes! Glad it's sorted out.

[Ivan Kelsall]

Steve - You're the second person to come up with exactly the same problem with DR 'G' strings in just a couple of weeks. The previous Cafe member also had a 'dud' G string. I've been using DR MD11's for 18 months or more & fortunately haven't had this problem. I did have the same problem a few years back with a set of J74's & it was weird. I also swapped the strings around & the problem swapped over as well = a dud string. I put on a new string & it was fine.

As a DR user in the UK,i doubt very much if DR will send me any replacements if i get the same problem,so,i'm hoping that DR have a good look at what might be happening & get it sorted out. As a % of the quantity of strings that DR or ''any other maker'' produce,i feel that such problems are minute,however annoying to us,
Ivan