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Mastertone setup advice adjusting the string height

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Aug 13, 2020 - 10:30:23 AM
3 posts since 6/29/2020

I recently acquired a 1998 Gibson Mastertone RB250. When I play in any fret above the fifth fret, it seems more difficult to get a clear tone than I would expect on an instrument like this. Since I have very little experience with banjos, I don't really have a good basis for comparison.

That said, I suspect that I need to adjust the neck to bring the strings closer in the higher frets. I've read quite a bit about coordinator rods and truss rods, but it's not clear to me whether I should attempt this myself. Some web sites make it sound simple; other sites make me think I'll over-stress the instrument if I don't know what I'm doing. The local guitar shop says they can adjust it, but I don't know how much they really know about banjos in general and Mastertones in particular. Plus they want to keep it a week.

The string height at the twelfth fret looks to be an eighth of an inch. The neck appears to be straight with no bowing. Is there a "standard" height I should target, if I attempt this? I've seen where some people measure from the twelfth fret and others from a higher fret. Or do you just experiment until you get close as possible without the buzz?

Any advice welcome here about whether I should attempt this, what the risks might be, and how to go about it.

Thanks,
Robert

Aug 13, 2020 - 10:40:29 AM

ChunoTheDog

Canada

323 posts since 8/9/2019
Online Now

Is your issue that the string height is acceptable at the 12th fret, but too high up by the headstock? Or is it too high all across the neck?

Do you happen to know what bridge height is on your Gibson (standard bridge is usually 5/8 or a little higher).

If your neck is straight and you dont get buzzes at the moment, needless to touch the truss rod in the neck.

You can in fact get the action down a hair by forcing the heel of the neck downward via the coordinator rod, we're talking like 1/4 turn of the nut to achieve a very very small lowering of the strings. But an inexperienced person shouldnt mess with the coordinator rods unless they understand what they do and how to use them.
It's not so much a question of breaking anything, it takes a lot more abuse to ruin a rim than tightening down on the coordinator rod a tiny bit. It's more about over tightening it and muting or choking the sound of your banjo.

In short, the quickest/easiest way to lower string height is by using a shorter bridge.

Edited by - ChunoTheDog on 08/13/2020 10:41:25

Aug 13, 2020 - 11:05:26 AM

7616 posts since 8/28/2013

First off, check the bridge height.

I would not touch the truss rod, although a small adjustment of the coordinator rods might help. I don't really think 1/8 inch string height at fret 12 is out of line; perhaps you just haven't yet developed sufficient callouses on your left hand. String height could possibly be adjusted down by 1/32 inch, but that's not much of a change, and any lower could cause fret buzzes.

I would not take a banjo to a guitar shop, just as I would not take a computer to an auto mechenic.

Aug 13, 2020 - 12:04:36 PM
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73295 posts since 5/9/2007

I would first check the head tension.

Aug 13, 2020 - 12:29:41 PM

495 posts since 2/6/2018

Agree, a loose head can dampen your playing significantly. That's typically the culprit given the issues you describe. Invest in a good head gauge.

Aug 13, 2020 - 12:43:05 PM

4187 posts since 6/15/2005

An eighth of an inch at the 12th fret is pretty much standard action for bluegrass banjos, give or take a 64th of an inch or two in either direction. Gibson's factory action was 7/64" at 12 and 9/64" at 22. So see what the action is at the 22nd fret. If it's in the same ballpark, it may just be a matter of your getting used to it.

But do check your head tension, as Steve suggests. Search the HO for his straightedge and dime or quarter procedure. You'd be surprised at what head tension can affect.

One more thing: what is your bridge height? Most banjos come with a 5/8" bridge (Stelling is a notable exception at 11/16", but he sets his necks to accommodate that size). Half-inch bridges usually can be used to lower the action, and .656 bridges usually can be used to raise the action, without having to adjust the neck angle.

Aug 13, 2020 - 1:04:47 PM

13255 posts since 10/30/2008

String height above the frets doesn't really affect tone of a properly fretted string. If the banjo is properly set up otherwise.

I suggest something else may be wrong. If you happen to be accustomer to playing electric guitar, you're going to have to work on a "firmer" left hand touch for best tone from a banjo.

You may find that LIGHT GAUGE strings would make it easier to get a pleasing tone.

Aug 13, 2020 - 1:08:14 PM
Players Union Member

RioStat

USA

5262 posts since 10/12/2009

You say you just got the banjo.....so maybe a new set of strings, if you haven't done that yet.

Aug 13, 2020 - 1:39:30 PM
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11086 posts since 6/2/2008

quote:
Originally posted by rwreagan

When I play in any fret above the fifth fret, it seems more difficult to get a clear tone than I would expect on an instrument like this. . . . I suspect that I need to adjust the neck to bring the strings closer in the higher frets. 


Head tension is always good to check when the main problem is tone.

But if you think your problem relates to string height, tightening the head is going to elevate the bridge and raise the strings a little.

Bridge change is definitely the low-impact way to bring the actiondown. But I think going all the way to 1/2-inch from a likely 5/8-inch is drastic.  With a really low bridge, you have to work harder to keep from hitting the head with your picks. Some people think there's a correlation between between low bridges and low volume.

So do check your current bridge to determine that you don't have an 11/16 or .656.  If you have one of those, then moving to the next one lower would be a logical first step. From 11/16 come down to .656. If that's what you already have, come down to 5/8.

If you have a 5/8-inch bridge and want to try something less tall, Richie Dotson sells a .600. Good sounding bridges. I have one on my '70s RB-250.

More to the point: Why do you think string height is the issue? Is difficulty depressing the strings what you mean by "difficult to get a clear tone"?  Once you get an up-the-neck note fretted is the tone clear?

As to your other questions . . .

1/8-inch at the 12th fret (measured from the top of the fret to the bottom of the string) may well be the average or consensus for comfortable action. I think Deering standard is 1/8-inch at 12. As Arnie said, Gibson spec was a touch lower.

You're right that some people prefer to measure from other frets. I'm one of those. I prefer to measure at the 22nd fret because that tells me the highest action anywhere on the neck. Everywhere else has to be lower. These days, I like 1/8-inch at the 22nd fret. Though 1/32 to 1/64 less than that is good, too.  I guess I liked Gibson spec.

Truss rod affects string height in the low frets by adjusting "relief," the amount of up-bow resulting from the tension of strings pulling on the neck. It has less effect in the upper frets. There, the coordinator rods can be safely used to raise or lower string height a small amount.

Truss rods should only be adjusted if relief is so low that strings buzz in the first 5 frets or so high that action is too high in the middle of the neck.

It's true that incorrect or excessive adjustment of coordinator rods or truss rods can lead to neck damage. Anyone unsure of what they're doing, shouldn't touch them.

But there's enough accurate instructional material on the web that anyone should also be able to measure their current set-up and safely make minor adjustments.

The biggest rule in truss rod adjustment is never force it. If the nut is putting up too much resistance to turn either direction, STOP. Take the banjo to a qualified repair person.

My favorite set-up video to share. First part is about setting the bridge. Skip ahead to 4:58 where Warren's guest, Donnie Little, shows how he uses very slight coordinator rod adjustment to tweak the sound.

Aug 13, 2020 - 3:05 PM

73295 posts since 5/9/2007

Do the simple stuff first.

Aug 13, 2020 - 4:16:57 PM

conniel

USA

741 posts since 5/1/2020

Well written ken! That’s about all I need to see for a good set up! Thanks for your expertise

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