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The ‘Gibsonbacker’ 12-string Electric Guitar

Ever since hearing John Lennon play on his Rickenbacker Guitar in the sixties, I longed to possess and play one myself. Adopted by so many groups during the sixties, the beautiful jingle-jangle found it’s way onto many of what still are my all-favourite records. Although I have played guitar now for over 35 years, I was never ever able to play one of these instruments, firstly because of their scarcity, then latterly because of cost, but now when there are plenty available and the cost is reasonable, I’ve found that there is simply insufficient room on the fretboard for my fingers! Naturally, I’ve looked for alternatives and these too, all have fretboards too slim for me to play without muffling notes.

Awhile back in 1997, I was working in London during the week, returning to Newcastle at weekends. A colleague and I had rented one of the new riverside-apartments in Rotherhithe. (posh name ‘Surrey Quays’) During one of my rare weekend stopovers in London, I went up to Denmark Street and bought an Epiphone Les Paul guitar. I already had a Fender Stratocaster and wanted to add an alternative ’sound’ to my arsenal. It cost me £149.95 and has been worth every penny. I brought it home, re-strung it with heavier strings, adjusted the set-up and let fly. It’s a bit of a beast, possessing a subtle tone that can be turned into a growl with just slight increase of plectrum force. I liked it so much that a year or so later I bought a ‘real’ Gibson Les Paul, that is truly magnificent – Black body and gold fittings and sounds as good as it looks.

This short article documents what I did to my Epiphone Les Paul to give me a playable electric 12-string. First some words of warning. If you fancy doing something similar there are a few things to be borne in mind:

  1. Sound Quality? If the candidate guitar sounds like a dog now, it probably will sound worse after conversion. A better pick-up may rectify this – but check first.
  2. No going Back? You may need to modify your instrument in such a way that should you not be satisfied with the result, you can’t return it to its original condition.
  3. Final value? DON’T attempt to modify a vintage instrument that has any real value because of it’s age or history – your modifications will not be appreciated by collectors, should you wish to subsequently sell.
  4. Risks? The major risk is the effective total destruction of your guitar. This can come about in several ways, but the most obvious is the application of more stress on the body, neck and headstock than what the guitar was originally designed for, due to the installation of 6 more strings. I discuss this later, in an effort to ameliorate the effects of adding more strings.

These comments refer to a guitar similar in design and construction to a Les Paul. I have added notes at the end which I hope will help those wishing to convert a Fender-type guitar.

My approach to the conversion is to make small, controllable changes, testing each in turn, with careful consideration to points 2 & 4 above. This way, you will remain in control and avoid disaster.

First of all take off the 2nd string (B) , and loosen the first (high E). Now thread an identical E string (either 0.009” or 0.010) through the hole in the body for the E string and over the 1st bridge part, with the down-most string (on a normal right-handed guitar) located in the original grooves on the bridge and nut and fastened to the 1st tuning peg.

Lie the duplicate E string a short distance away from the 1st E string on the bridge and nut and fasten it to the 2nd tuning peg.

Note. Don’t make ANY cuts at this point. The pictures below show the relative positions of the strings at both the bridge and nut, with the down-most E string in its original position and the duplicate located a short distance away.

Bridge, Showing String Positions

Bridge, Showing String Positions

Nut, Showing String Spacing

Nut, Showing String Spacing

More words regarding string-pair spacing.

Please note that string spacing is an individual thing – no two persons fingers are the same. I left a relatively large space between each string pair, as there is sufficient width on my Epiphone Les Paul fretboard, to do so. If there is insufficient spacing between siblings, then rattles and buzz will result from over-enthusiastic plectrum action. Also playing style can affect the effective distance between pairs. For example a finger placed on a string pair at an angle will tend to force the strings closer to each other. On my guitar above, you will notice a greater spacing on the 3 lowest string pairs for this very reason.

 
Now tune up the new E strings, so that they are of identical pitch. Plug in to your favourite Amp and try out the guitar (remember you’ve removed the B string!) Be gentle with the E strings as only the down-most is securely located. Adjust the spacing of the duplicate E string so that it is comfortable under your fingers, and you can fret both E strings without them fouling each other or the phantom B string – if it was there! If you don’t like what you hear – then give up and remove the extra string, once more returning the guitar to it’s original condition. If you do like the result, note the final position of the duplicate E string at both the nut and bridge, (I used very fine write-all pen) then go on and do the same exercise to the 6th string, (low E) again without making any cuts to your guitar. This time using regular gauge 6th string and a lighter-gauge octave string. I was lazy and purchased a pack of D’Addario XL Regular Light 12-string Cat. No. EXL150, The lighter E string should again be located parallel and upper-most to the original 6th string which occupies it’s original grooves in both bridge and nut. After tuning, power-up and test the new string combination. If you are happy then continue reading this, if not, simply re-string your guitar as normal, and the exercise has only cost you a little time.

 
If you are happy with the sound tests above, then it’s time to forage for a set of individual tuning pegs that will be added to the guitar headstock. I wasn’t concerned with the aesthetics of the finished product, (pretty it ain’t) so I bought a cheap set of pegs from a dealer on the Web. On my guitar there was insufficient space to add all six guitar pegs around the perimeter of the headstock, so I substituted two banjo/ukelele pegs for location in the centre. (see pic below)

Headstock, Showing Extra Tuning Pegs

Headstock, Showing Extra Tuning Pegs

I proceeded in what I hoped was a logical fashion, starting with high E, (1st string) partially dismantling the new peg mechanism, offering it up to the rear of the headstock and carefully marking the position of both the peg-hole and fixing screw holes with my fine write-all pen.

I was prepared to measure everything and try to maintain symmetry – this idea was abandoned for two reasons:

  • The guitar headstock is not symmetrical. Examining it closely reveals subtle differences between each side of the headstock – presumably for aesthetics.
  • A need to fit the extra pegs in a way that will not unduly weaken the headstock – this may mean offsetting pegs rather than having them all in a straight line.

I then drilled (on the rear of the headstock) the fixing screw holes with a fine drill, (1mm) and also drilled through the headstock with this fine drill for the peg-hole, repeating the peg-hole drilling in turn with 2mm, 4mm and 6mm drills, this time from the front of the headstock. Be very careful with the peg-hole drilling, especially the largest size operation – splitting the headstock will ruin your guitar. In fact a good idea of what you are drilling into will be obtained by removing one of the existing tuning pegs and inspecting the peg-hole. I discovered that the headstock on my Epiphone Les Paul is some sort of composite material – easily drilled and not prone to splitting as there is no grain – be careful anyway! The new tuning pegs come with a ferrule which is to be inserted into the front of the peg-hole. These vary in size, so you should check the diameter of the ferrule, and use an appropriate drill. They are serrated laterally and are intended to be a push-fit. DON’T make the holes too small – undue force whilst fitting a ferrule into an under-size hole risks splitting the headstock. Better loose than too tight. In fact after taking one of the original pegs out to ascertain the type of headstock material, resulted in the peg ferrule dropping out onto the floor – a silent comment on the build quality of these Korean-made guitars.

After completing each peg installation, location of the duplicate string on both the nut and bridge was carried out. (after a sound test) I cut shallow notches in the plastic nut using a fine coping-saw blade, and filed a notch in the bridge-piece using a fine triangle-section needle file. On my guitar, the holes in the stop tail-piece were too small to accommodate an extra ball-end. My solution was to clip off the ball-end (and twisted string) and thread the string through the centre of the sibling string ball-end, twisting the string back on itself (gently) and soldering the twisted section to secure. Both strings are now terminated on one ball and can be inserted in the tail-piece easily. Note that where you have a plain wire and a wrapped-wire pair (heavier-gauge), always remove the ball-end from the lighter-gauge string, and thread this through the middle of the ball-end of the heavier-gauge string.

With each peg/string installation, try to maintain the straightest pull-line of each string – especially beware with the lower-most and upper-most strings – too acute an angle to the nut may break off the end of the nut where you have cut the new notch.

May the force be with you….. A few words here on the extra stresses introduced by fitting another 6 strings. A helpful table is provided on the rear of the D’Addario EXL150 12-string pack, giving useful information on the tensions required on each string for correct tuning. I’m sure D’Addario won’t mind if I reproduce part of the table here, so that putative string users are given an idea of the forces involved.

Table 1. D’Addario EXL150 12-string pack details

String No.

Ball-end Colour

Diameter (inches)

Tension (Lbs)

Extra Tension

1:E

Silver

0.010

16.2

 

2:E

Silver

0.010

16.2

16.2

3:B

Purple

0.013

15.4

 

4:B

Purple

0.013

15.4

15.4

5:G

Green

0.017

16.6

 

6:G

Green

0.008

14.7

14.7

7:D

Black

0.026

18.4

 

8:D

Black

0.012

18.5

18.5

9:A

Red

0.036

19.5

 

10:A

Red

0.018

23.4

23.4

11:E

Brass

0.046

17.5

 

12:E

Brass

0.026

23.2

23.2

As you can see by totting-up column 5, your guitar will be subjected to an extra 111 Lbs or so tension from headstock to bridge. My Epiphone Les Paul shows no signs of being uncomfortable with this extra tension, other than the action being a little higher than with the original 6 strings only. I decided that I was quite happy with that, (I have big strong hands) so have not adjusted the truss-rod to compensate. If you are in any doubt as to the strength of your guitar build, then proceed with caution, fitting one extra string at a time, tuning up, and checking the action, listening for any ominous creaking noises etc., before moving on to add the next string. Proceeding in this way will at least save your guitar from total destruction in the event of it being too frail to take the extra strings. It is entirely possible to reduce the loading on the guitar by substituting strings other than those of the diameter given. In this case the use of either a digital-vernier or micrometer to measure diameters is very useful. BTW I discovered that some strings are not exactly the diameters stated by the manufacturers, sometimes being out by up to 2 thousandths of an inch – it may not sound much but the reality is that it’s 20% on a 0.010 gauge string!

What’s in a name?

I nicknamed my creation ‘Gibsonbacker’, to reflect it’s split personality.

Anyway, I salute Gibson for making available a superb guitar at such a reasonable price, and Rickenbacker for inspiring me to jump in with both feet in converting the guitar into an easily-playable 12-string electric that has a truly amazing sound.

The Completed Instrument

The Completed Instrument

Notes for players wishing to convert Fender-style guitars.

The major difference in converting a Fender-style guitar is with the bridge assembly. Each bridge piece on the Fender has 2 grub screws for height adjustment and a laterally inserted screw for adjusting the effective length of the string. You will need to remove each bridge piece in turn, remove the grub screws for safe keeping and turning the bridge piece over, carefully file a quarter circle in the slot on the opposite side to that which previously supported the single string. Do this for the 1st E string only at this point so that you can test the result before proceeding. Re-fit the bridge piece and original string together with its new sibling laying the 2 strings on either side of the slot on the radius you have just made. The strings should be joined at a single ball-end as described for the Les Paul guitar. Tune up and try the new E string pair out, adjusting the new duplicate at both the nut and bridge to give sufficient spacing. When you are satisfied, mark the new E strings position at the nut, and the position of both E strings at the bridge, then remove the bridge piece and grub screws, locate bridge piece in a vice and file notches in it and a new notch in the nut, before re-fitting and testing again. That’s it really. Follow the text above for my remarks on fitting the extra tuning pegs. The picture below shows a Fender-style bridge with 4 strings added. (Pignose guitar converted for bouzouki tuning)

Pignose Bouzouki

Pignose Bouzouki

The following were added 1 June 2009 hopefully showing the headstock a little clearer.
Headstock FrontHeadstock RearClose-up showing bottom tuners clear of neck

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