1st string raise
Moderator: Shoshanah Marohn
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Marc Weller
- Posts: 280
- Joined: 11 Sep 2000 12:01 am
- Location: Upland, Ca. 91784
1st string raise
The first string raise on my MSA returns flat when I release it. I thought maybe my string was slipping but I replaced it with no improvement. Any help trouble shooting this would be appreciated.
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Tucker Jackson
- Posts: 1605
- Joined: 8 Apr 2004 12:01 am
- Location: Portland, Oregon, USA
Hi, Marc.
Question: what happens if, after it returns flat, you press on that string inside the keyhead near the tuner? I realize that 1st string is a really small segment so...it's hard to do.
If it comes back to pitch, that indicates the roller nut is not turning freely. Ideally, it should allow changes in string tension to transfer freely over the roller such that tension is equalized on both sides of the nut. But when the roller binds, tension does not completely equalize for a second or two... and raised strings return flat.
Try loosening the string and seeing if the roller will turn. Lubricate it. And then make sure you have the string wound onto the tuning post such that it as much in a straight line with the longer piece of string on the other side of the roller nut as is possible.
If you're interested in the physics of why a raise (confusingly) comes back flat, your knee lever force is strong enough to overcome any roller stickiness, so there's no problem on the raise part of it -- but when you release the knee lever, the force in play to lower the pitch is just string tension that's being released. This isn't as strong as your knee lever force, so if there is any stickiness in the roller, a problem can now appear.
The issue is that, due to the roller binding and not letting the string move freely, all of the released tension isn't properly distributed across the roller nut and down the entire length of string all the way to the tuner; instead, it's just concentrated on the segment from the changer to the sticky roller. And on the other side, the tiny string-segment inside the keyhead ends up with a little too much tension leftover from when you did the raise -- tension that wouldn't properly release back over the roller nut when you released the knee lever. So you momentarily end up with too much tension on the keyhead side of the nut... and not enough on the other side of the nut (leaving your pitch flat). Over several seconds of hitting that string, it will generally come back to pitch as the vibration coaxes the string to wiggle a little over the nut to the left to equalize tension on both sides of it.
Question: what happens if, after it returns flat, you press on that string inside the keyhead near the tuner? I realize that 1st string is a really small segment so...it's hard to do.
If it comes back to pitch, that indicates the roller nut is not turning freely. Ideally, it should allow changes in string tension to transfer freely over the roller such that tension is equalized on both sides of the nut. But when the roller binds, tension does not completely equalize for a second or two... and raised strings return flat.
Try loosening the string and seeing if the roller will turn. Lubricate it. And then make sure you have the string wound onto the tuning post such that it as much in a straight line with the longer piece of string on the other side of the roller nut as is possible.
If you're interested in the physics of why a raise (confusingly) comes back flat, your knee lever force is strong enough to overcome any roller stickiness, so there's no problem on the raise part of it -- but when you release the knee lever, the force in play to lower the pitch is just string tension that's being released. This isn't as strong as your knee lever force, so if there is any stickiness in the roller, a problem can now appear.
The issue is that, due to the roller binding and not letting the string move freely, all of the released tension isn't properly distributed across the roller nut and down the entire length of string all the way to the tuner; instead, it's just concentrated on the segment from the changer to the sticky roller. And on the other side, the tiny string-segment inside the keyhead ends up with a little too much tension leftover from when you did the raise -- tension that wouldn't properly release back over the roller nut when you released the knee lever. So you momentarily end up with too much tension on the keyhead side of the nut... and not enough on the other side of the nut (leaving your pitch flat). Over several seconds of hitting that string, it will generally come back to pitch as the vibration coaxes the string to wiggle a little over the nut to the left to equalize tension on both sides of it.
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Larry Bressington
- Posts: 2809
- Joined: 6 Jul 2006 12:01 am
- Location: Nebraska
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Lee Baucum
- Posts: 10326
- Joined: 11 Apr 1999 12:01 am
- Location: McAllen, Texas (Extreme South) The Final Frontier
Re: 1st string raise
How many cents flat?Marc Weller wrote:The first string raise on my MSA returns flat when I release it.
~Lee