Re-stringing a twelve is not too difficult if approached logically while being mindful of the much greater tension exerted on the instrument compared to six stringers, and it is therefore usually best to adopt a one string at a time approach when replacing them(actually a good approach for any guitar).
This guitar, a Japanese-made Jumbo branded for Bell Ltd music shop of Surbiton, Surrey (where Eric Clapton apparently got his first guitar) circa late ’60s was already missing some of its strings. However these trapeze tail piece designs are much better able to handle the stresses compared to string-through bridge types, and bellying of the soundboard is less likely to be an issue. This one, made out of solid mahogany and spruce, even employed the fan bracing construction typically found on nylon string classical guitars, rather than the stronger ladder or X bracing usually needed with steel strings. While it has a ‘steel reinforced’ neck (a la pre ’69 Martins), this is not an adjustable truss rod design, so the relative bridge position under string tension is critical to the action obtainable.
And indeed when fully strung and to pitch the bridge and top weren’t displaced much, and there was a reasonable action – pretty essential when you have two strings per course to fret. As the guitar’s fan braced top is so resonant I used a 9s twelve string set, which are considered light, to reduce the string tension a little. Another preservation approach for 12-stringers is to down tune a half or full step and use a capo on first or second fret; and releasing the tension on the strings is also a good idea when it’s not being played for an appreciable time (good tuning practice too). Since this guitar is principally for slide, a low action higher up the neck wasn’t a priority requirement. The trapeze tail piece made intonating the guitar easier than a string-through bridge, since the bridge is floating (another good reason for one at a time string change, so it doesn’t fall off), and can be angled and positioned for best intonation. The bridge is obviously non-original; I first thought it might be ebony, but in fact it’s hardwood painted black. I flattened the bottom off for better soundboard contact, and re-profiled it’s saddle slightly to help the strings’ break over positioning a little for the intonation. The actual break over angle itself is not as critical, as trapeze tailed guitars vibrate the sound board by moving it up and down, compared to string-through bridges where it is fundamental since there is more of a lever type rocking transmission of the sound vibrations.
This guitar did produce the characteristic chorus-like 12-string warble played acoustically, and had good tone and volume from the construction and old woods, but that wasn’t the end of the story.
It also has a ’50s era DeArmond 210 single coil pickup fitted across the sound hole (which has its on board volume control), and these need some adjustment to get a uniform signal balance across the strings when playing electric. This involves finding the best positioning in the sound hole (not necessarily vertical), and adjusting the height of the six individual magnet pole pieces in the pickup itself for the best volume balance. Although they have a respectable dc resistance (9.6 k ohms on this one), the magnets are relatively weak so they are pretty low output. It is at best all a compromise (later versions had fixed poles with the B string pole piece set much lower than the rest in an attempt to try to get the strings balanced better – the same theory as with Fender’s late ’50s staggered pole pups); plus I think really this pickup was designed for six string guitars. Proper electric strings (nickel) are best so that the plain and wound strings are better balanced, though this may limit the guitar’s voicing if say phosphor bronze strings are preferred for acoustic use.
But once set up, when played through a good valve amp having plenty of headroom (I used my silverface Fender Twin Reverb) it made a nice jangly sound, and it really got atmospheric with a little reverb dialed in. A dirtier sound can be interesting too (though I quickly tired of it) – if you can keep the feedback under control.
However, a Rickenbacker 360/12 it is not. (Rics have a different string ordering in the courses for a start.)