PRS nut compensation measurements - 25.5" scale

[David L Smith]

Customer brought in a 25.5" scale guitar which was previously butchered by someone trying to install a locking nut. I must rebuild the nut end of fretboard and re-route a new nut slot. What is the distance used by PRS on 25.5" scale length guitars for the nut compensation? Need distance between 1st fret and nut at low & high E strings. Tremonti Baritone hybrid tunes as C# .

[Barry Daniels]

Why would you think that PRS uses compensation at the nut because that would be somewhat unusual. You can determine the uncompensated length from a fret calculator. Stew Mac's online fret calculator gives the distance as 1.431"

[Mark Swanson]

It's done on a lot of guitars. It was originally part of the Buzz Feiten thing, but plain old nut compensation is used now on many. It is effective, I like it.

[Brian Evans]

It's unclear to me whether PRS uses a Buzz Feinten type staggered nut, or just moves a normal nut closer to the first fret than might otherwise be the case. Except in custom signature models it usually has a 25" scale, very rarely 25.5". PRS guitars usually ship with .009 - .042 strings, some with .010 - .046 strings, and the .009's in particular need more nut or otherwise compensation than stiffer strings, in my experience. But there definitely is a lot of talk about PRS and nut compensation. I guess I do a little nut compensation in that I move the nut a half saw kerf closer to the first fret, but I haven't done a serious study on it. If I get the nut slots right I can't measure or hear the need for more compensation that what I put in, I use a wound third string which helps out the whole skinny G string deal, and I usually use .011 - .052's which again reduces the need for additional compensation.

[Barry Daniels]

I know it is done on custom guitars (in fact I do it too), but I didn't think that many factory guitars use nut compensation.

[Joseph Price]

PRS have always used a nut compensation where it is closer to the 1st fret than it "should be"

[David King]

I'd think compensation would dictate that the nut should effectively be further away from the first fret but maybe I don't understand the Buzz Feiten concept. I've always just carved out little hollows on the front face of the nut until the first fret was in tune with the open string.

[Barry Daniels]

I like that Keep-it-Simple approach, David.

I have a 2002 Martin in my shop right now for an intonation fix. Can't decide whether a compensated nut is necessary or not. The bass side of the saddle needs to be moved back about 1/8". I think I will look at your nut fix first.

So when you do this, does it work like saddle compensation? For example, tune the open string, then if the first fret is a bit sharp then you need to lengthen the distance by carving the nut back a bit?

[Mark Swanson]

Barry said, "So when you do this, does it work like saddle compensation? For example, tune the open string, then if the first fret is a bit sharp then you need to lengthen the distance by carving the nut back a bit?"

Not the way I understand it. If the first fret is sharp, then that means the fret is too far away from the nut, and the fret is placed "too far down" the scale length and is playing the note sharp. So, the fix is to move the nut closer to the fret, by removing a little off the end of the fingerboard and reducing the distance between them. The amount you use varies with each string, so you need to move the nut in for the string that needs the most compensation, then cut each string back into the nut from there if they don't need as much.

[Joseph Price]

I've done this on a number of guitars. 0.8mm off the 1st fret to leading edge of nut slot
works well on Fender scale length.

[Clay Schaeffer]

From another perspective-
On you tube, an old guy, James Taylor offers a method for tuning a guitar with an uncompensated nut, which semi- progressively tunes each string flatter. High e -3 cents, b- 6, g-4, d-8, a-10, and low e -12 cents. He's a pretty good guitarist and seems to know what he's talking about.
By shortening the distance the from the nut to the first fret you allow the open strings to be tuned up to pitch, but give the advantages of the "flat" tuning Taylor uses.

[Barry Daniels]

Mark, that makes sense.

[Bill Raymond]

On the MIMF links page (accessible from the Home page) there is a link to Stephen Delft's article on compensated nuts: http://www.mimf.com/nutcomp/

[Paul Rhoney]

Anybody know if this is at all applicable on a neck with a zero fret?

[Barry Daniels]

It won't work with a zero fret.

[Bill Raymond]

All you can do with a zero fret is set it a fraction closer to the 1st fret. Chet Atkins had put a small peg just forward of the zero fret on his favorite '59 Country Gentleman for the G string to make it intonate a bit better, but I've not seen anything more elaborate to compensate each string with a zero fret.

[Dan Smith]

On the MIMF links page (accessible from the Home page) there is a link to Stephen Delft's article on compensated nuts: http://www.mimf.com/nutcomp/

This makes sense to me.
Thanks Bill!
Dan

[Barry Daniels]

I just did a compensated nut on a 2001 Martin D-35 with a bass E-string that the client said was pretty far off. Using Stephen Delft's method, I cut .030" off the end of the fretboard to set the compensation for the e, D, and A strings. The B string received a notch back .030" so it was where it started. The G string got a shim of another .013" and the E string got a shim of .084" making a total compensation of 0.114" for the 6th string! But it made the saddle work pretty much as it was originally made. Everything ended up sounding really sweet. Any thoughts on why this Martin had such a wonky E string?

One additional technique that I used to enhance the Delft method is he does not calculate nut compensation but just keeps adding shims until the tuner says good. I used Frank Ford's method of calculating saddle compensation but used it for the nut, and it seemed to work fine. That method is as follows and was performed after fully compensating the saddle:

NUT COMPENSATION
1) Tune open string.
2) Fret at 12th fret and using a tuner that reads cents determine cents off, sharp or flat.
3) Get the distance from nut to first string based on fret calculator, like Stew-Macs online tool and your guitar's scale length.
4) For each string multiply the 1st fret distance by the number of cents off and divide by 100.
5) If the string was sharp then that product of the step above determines the shim to add, and if flat then how far to notch the nut.
6) Like I stated above, three of my strings were 2 cents sharp so I moved the whole nut closer by cutting a bit off the fingerboard and the other string's compensation values were adjusted accordingly.

[Mark Swanson]

That sounds great! It sure makes a large difference, I think. It's so nice to really hear everything so in tune.

[Barry Daniels]

I did not have much experience with this Martin before the work so I had no basis of comparison. But my client said it not only sounded sweeter, but that it was louder too. I don't know why that would be. I wouldn't think compensation would affect volume.