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hello,

I did some repair work on a freinds guild 12 string( first 12 string i worked on) re-glued/repaired bridge,new saddle and nut an new jdl bridge doctor to counter bellying behind the bridge. by the way cant play just build so this im not sure if there was a general string space mainly between strings of the same tunings. i could measure the space on the old nut and saddle but i dont know if they are right. also is the action different than a six string? and would the saddle be slightly notched to maintain string spacing?


thanks for the help
brent

Hi Brent,
12 strings are usually about the same action height as 6's. Depends on how hard you pound it. As far as spacing of pairs, 3 mm usually works on the bass side and maybe 2 on the treble...depending on the string guages. Depends on the tuning of the instrument too. Most 12 strings are tuned down from E.

Brent, different 12 string players can have fairly different opinions on what setup they like. I'll tell you what I like, but first, a clarification. I play fingerstyle with a fair amount of slide. I downtune and use open tunings on three different 12's. Here is how I set them up.

I use pretty standard 0.110 - 0.120 spacing from the edge of the fretboard to the outside strings. I also like about 0.110 between strings. The closer you make them at the nut the easier the course is to fret, but if you get them too close at the saddle there is a change the vibrating envelope with clash together. Spacing at the saddle is set by pin holes and any ramping - if you used the original bridge there isn't much you can do there. I have heard of players who like wider spacing at the saddle and can pick each string of each course individually - I just stick with about 0.110 on all the courses, maybe less on the trebles.

I set the nut action basically to the zero fret line just like you would do with a sixer and about the same 12th fret action. I like 20 inch radius fretboards for slide, but see no reason to set the action particularly high - somewhere around 0.080 high E and 0.090 low E seem to work fine with around 0.040 relief and 12's tuned to D.

You can affect the sound of a 12 string by which strings are anchored closest to the saddle - my old D12-28 has the octaves closest but I think there is some advantage to putting the primaries there (the new Martin J12-40 is that way). Obviously not something you can change unless you are replacing the bridge. You can also really help the up the neck playability by compensating each string individually - takes a little more time but 12 strings usually have pretty bad intonation.

Last comment, when my D12-28 developed a bit of a belly I tried a JDL but it made the break angle so shallow (I used the kind with the holes in the pin heads) that there was almost drive to the top. Resetting the neck (which it really needed) reduced some of the bulge and gave much better break angle.