Intonation issue w/ new neck -- do I have to move my bridge
 

I recently replaced the neck on my Fender American Jazz bass with a neck from a Deluxe American Jazz Bass. It was a straightforward replacement, and with some minor truss rod tweaking, the neck is straight and the action is fine. Problem is, it just won't intonate -- it's consistently nearly 20 cents flat at the 12th fret.

My theory on this is that the bass's original neck was the standard Fender 20-fret, while the replacement has the 22-fret neck. Has going to a slightly longer neck without moving the bridge caused the intonation point to move?

If so, is there a fix short of moving the bridge around? I've got tools and am relatively competent, but if it involves anything too heavy, I'm just going to take it somewhere. I just kind of want to satisfy my own curiosity.

Any help is much appreciated -- thanks in advance.

To diagnose, measure the distance between the nut and the saddle*. It should be very close to 34 inches. If it's significantly longer (34.25+) then you need to move the bridge or get a neck with same number of frets as the original. *you can also measure half the scale length by measuring from the saddle to the 12th fret, which should measure very close to 17 inches.

That's exactly what happened. More frets = more notes = longer neck. The 22 fret neck placed in a 20 fret neck pocket has resulted in a longer scale instrument. Moving the bridge to a standard 34" scale placement is the only fix if you want to keep that neck. But changing back to 20 fret neck would be the optimum choice IMHO. If you move the bridge, you'll also affect the base tone of the instrument in an unpredictable way.

Ah, thanks guys. I kind of want to keep the neck for the little bit of extra range, but can anyone else weigh in on how moving the bridge would affect the instrument's tone?

moving the bridge shifts the relative position of the pickups when compared to traditional Fender pickup spacing.

Also, you can get necks that have extra frets which "overhang" without messing up the scale length: http://www.warmoth.com/Bass/Options/BassNeckPocket.aspx

By having to move the bridge to accommodate the longer 22 fret neck, you're also essentially moving the pickups that same distance closer to the bridge.

He's moving it back, not forward...pickups are farther from bridge, no?

Cool, okay. Thanks, everyone!

You could probably finance a Warmoth 22-fret neck with the sale of either of your Fender necks.

No... my first answer was correct.

He's thinking about putting on a longer 22 fret neck. That means the nut will now be further from the bridge. In order to maintain the same 34" scale length, the bridge has to move towards the nut. The pickups are in a fixed position so that means the bridge will actually move closer to the pickups.

Thx.

Uh, from what I recall regarding twenty two fret aftermarket necks like this, the change in size is more an overlap at the neck pocket side, not at all changing the length of the neck or distance from nut.

Picture's worth 1,001 words:

http://www.warmoth.com/Bass/Necks/Ba...retBoards.aspx

Edit: Woops, I see somebody mentioned Warmoth, but it wasn't the OP. The OP said he's using a neck from a Deluxe American Jazz Bass:

1). OP still hasn't measured from nut to saddle; if he did, he hasn't posted;
2). I'd be completely amazed (it's happened, won't rule it out!) But perhaps surprised is better word? If the neck from this American Deluxe is longer than a standard Fender-length neck. BTW OP, I find the American Deluxe on Fender's site with 21 frets, what year is your 22-fret out of curiosity? http://www.fender.com/series/america...uxe-jazz-bass/

I don't like the extended fingerboard necks. There's a chance they can "ski jump" and the access to the extra frets isn't very comfortable.

No more chance to ski jump, than a non-extended fingerboard.

OP: have you made certain that there are witness points at both the nut & saddle? And have you measured the scale length?

I was unable to find out whether the neck pocket is routed differently for a 22 fret neck; if so, you do have a problem. If not, there's something else the matter, here.

The OP said it was a straightforward replacement. I take this to mean that his 22nd fret is where his 20th should be. There is no clean solution to this. Moving the bridge will fix the intonation, but change the focal points of the pickups. (and likely leave scars from the original bridge) The "correct" solution would be to rout the neck pocket and pickgaurd further into the body. But that's not very correct either, as it will leave the neck pocket rather loose. It would also require a custom made pickgaurd should that ever become desirable. The actual correct solution is to get a correct neck for the body.

"The actual correct solution is to get a correct neck for the body." Indeed.

I am thinking we are chasing red herrings here. And the OP hasn't been around in a while, seems a wasted effort anyway. Unless there's significant damage to your original neck, OP, can't think of a reason why you need this new one? That doesn't seem to be working for you whatever the reason?

Hey sorry for the absence.

Yes, it is a replacement neck from a Fender Deluxe American Jazz bass. Original neck had damage to it (chunks out of the back that wood filler was only a partial fix for, some warping) from the previous owner, so I saw the opportunity for a direct replacement (or so I thought) and went for it. The body is from an '03 Fender American JB, the neck from an '08.

I did measure the scale length and found that's it's about 35 inches now, so moving the bridge is probably the only fix. That idea doesn't necessarily bother me, since I'm not a huuuuuge tone purist (actually, the idea of having a wonky, not-quite typical tone is kind of appealing), but I don't want to push a fix that's going to leave scars and/or just seem stupid.

Bummer. I guess the real lesson here is trying to be frugal doesn't work unless you've done your homework. Thanks for everyone's help. Much appreciated.

I did measure the scale length and found that's it's about 35 inches now,
 

Is this twice the measurement of the leading edge of the nut, to the center of the 12th fret?

Were you able to mount this neck using the existing screw holes? Something is just not adding up, here.

This. Confused, but intrigued.