distance from nut to 12th fret

[madlee]

I have a Fender MIM Precision Bass that I'm trying to intonate. I can tune all four open strings, but once I begin to move down the scale, it starts to go sharp.

I measured the distance from the nut to the top of the 12th fret and it is about an 1/8" short of being 17". How precise should this distance be and if it should be exactly 17", do you think I have recourse with Fender? I bought this bass a little over a year ago. It has a lifetime warranty.

I haven't done any modifications to this bass.

[J.D.B.]

The strings are tuned to pitch open, are they at their respective octaves at the 12th fret? Check this out. Generally, on a 34 inch scale instrument, the distance from the bottom of the nut to the crown of the 12th fret should be 17", and then 17" to the nearly fully extended saddles. The length to compensate won't be shorter than 34" but it may well get longer. There is always a compromise in between these hard points as to fret locations. I usually find the notes a tad sharp as I move up the neck on a properly set up instrument. A tad, not a ton. If you have the hard points dialed in on the instrument and are very sharp in between then the "fret location compromise" is too far off and you'll need to find a better neck or live with it. I've seen some instruments set up with slightly flat basic intonation to mitigate the note sharpness in between. An 1/8" short from the bottom of the nut to the crown of the 12th fret isn't uncommon to find. The closer to 17" the better, but that's part of the money spent. If you're up to it, you can remake the nut to get the last 1/8". It'll help but not a helluvalot. This compromise that is the fretboard has been somewhat remedied by the method of installing the frets "fanned" as in the Ralph Novak "Novax" necks. Have fun learning and manipulating this stuff. It's quite addictive.
Josh

[madlee]

I believe it's about 2-5 cents sharp (at the 12th fret). I remeasured it and it actually is 1/16" off, from the bottom of the nut to the center of the 12th fret. Still, it seems odd that it would be off by that much. That is a considerable amount of wood to remove to insert the nut.

Thanks for the info. I had no idea that it was as much of an issue, and makes me think that maybe the neck isn't so bad after all.

[fretlessrock]

Adjust the saddles so that the 12th fret harmonic matches the 12th fret while fretted. While you are dialing it in you can forget about being at perfect pitch and just get them to match, then tune to pitch and make any minor correction if needed.

[Bofee]

Don't pay any attention to the nut to 12th distance, that's totally irrelevant. It is what it is. Set it up for intonation. Plug into a decent chromatic tuner, open tune the bass, then check the pitch up the neck with the tuner. If it's going sharp, increase the string's speaking length. Repeat. Simple.

[madlee]

It turns out that the issue is probably because I switched to the jamerson set of flatwounds and didn't adjust the neck. I put the roundwounds that came with the bass back on this morning and voila...it's completely in tune.

I guess I'll leave the roundwounds on for the time being.

[knuckle_head]

Originally Posted by madlee

It turns out that the issue is probably because I switched to the jamerson set of flatwounds and didn't adjust the neck. I put the roundwounds that came with the bass back on this morning and voila...it's completely in tune.

I guess I'll leave the roundwounds off for the time being.

If you change brands this phenomena is more frequent, but it's normal even when changing strings. You should always check your setup and intonation with every string change even if you're keeping with the same brand of strings.

It's more a bridge adjustment than a neck adjustment, and a pretty simple one at that.

[madlee]

I meant to say I'll leave the roundwounds on...

the labellas are much heavier and must've impacted the neck. I tried adjusting the intonation at the bridge, but no matter how much I lengthened the string, it still was sharp.

[knuckle_head]

It is also fairly common to have factory set bridges located too far forward - its something you don't notice until you go to B or up your gauges significantly.