Hi from the Straits of Mackinac in northern Michigan. 
For those who ever wanted to have a bouzouki but were scared away by the price, 
this super easy 'conversion' of a regular 12-string guitar into a bouzouki 
might fill the bill.

While this article may be of some interest to bouzouki hotshots, 
it's primarily meant for anyone not having a bouzouki but wanting 
to get into playing one.    In general, if the guitar sounds & 
plays nicely as a 12-string, it'll prove likewise when bouzouki-ized.
I like playing this conversion every bit as much as playing my commercially 
made zoukis. For a lot of tunes, I like it even a bit more, given it's droney 
sympathetic strings.

All that's involved is simply changing the gauges of the guitar's strings. 
Doing this means less (not more) overall string-tension on the 
instrument - 197.2 lbs of total strain (at regular string  pitches) 
on the bouzouki conversion vs 263.4 lbs total using standard Martin 
M190 12-string guitar strings.*

I used an nice old Epiphone/Gibson 12 string for this conversion. Nothing need 
be modified or changed on the guitar - just the strings.

For reference in this article, I've numbered the strings like this (1st string 
referring to the guitar's high E).   After a LOT of experimenting, 
I ended up using these gauges:
1st string pair   - .010/.010 (bouzouki E)
2nd string pair - .014/.014 (bouzouki A)
3rd string pair - .024W/.012 (bouzouki D)
4th string pair - .040W/.016 (bouzouki G)
5th string pair - .016/.016 (sympathetics but occasionally played)
6th string pair - .012/.012 (sympathetics but occasionally played)
Lower-pitched wound strings were initially used for the 5th & 6th pairs but the 
thinner, plain steel ones seemed to resonate better.
elderly.com in Lansing, Michigan sells individual strings.

To have the sympathetic strings resonate in different keys:
I either tune the two extra string pairs to resonate sympathetically with whatever 
key the bouzouki strings are being played in OR you can keep the thing in 
(high-to-low) EADGGD tuning (optimum sympathetic string tuning for playing in 
the key of G) and simply reposition the capo accordingly:
Key of A, put capo on 2nd fret
Key of C, put capo on 5th fret
Key of D, put capo on 7th fret
The higher the capo goes, the more it starts to sound like a regular mandolin 
rather than a bouzouki, because of this I like to retune the sympathetics when 
I play in D.

RE.  Suggested sympathetic string tunings:
D, G and A (& their relative monors) are the keys I mostly play in and I tune 
the sympathetics accordingly. Here are some suggestions. Generally you can tune 
the sympathetic pairs to any note of the desired chord - 1sts, 3rds, 4ths, 
5ths & minor 3rds (note that the 5th string pair in this conversion is a 
purposely heavier gauge than the 6th string pair):
Key of D sympathetic string tuning: 
A
A
D
D
Key of G sympathetic strings tuning:
G
G
D
D
Key of A sympathetic strings tuning:
A
A
D
D

Key of C sympathetic strings tuning:
G
G
C
C
The key of G is my favorite on this instrument - especially when the 
sympathetics are occasionally hit along with the bouzouki strings. 
Resonance abounds what with 8 strings sounding a G chord. I tend to 
keep the instrument in G: (high-to-low) EADGGD.

A quick few words about (hi to lo) EADG vs DADG tuning:
In my alternate world of Celtic/O.T. fiddling, I greatly lament that 
so many are forsaking using variant tunings. Much is often lost by 
playing tunes in standard tuning that are meant to be played in tunings.
Having said that, on bouzoukis, I prefer to use (lo to hi) 
EADG instead of DADG tuning (for several reasons I'll not get into 
here) but this conversion will obviously work fine for either EADG 
or DADG -- perhaps a thousandths thinner high-D strings if desired.

While the thing works fine with the bouzouki strings tuned to regular 
pitch, for over a half-century, whenever I play in the key of D on a 
fiddle or mandolin-family instrument, my personal preference is to 
raise the lowest note from G to A. On this instrument this makes for 
the bottom 10 strings all sounding in a D chord.
Likewise, if you raise the bouzouki part's G to A and it's D to E, you 
get all 12 of the strings singing away when you play tunes in the 
key of A.

If you'd rather not retune the sympathetics when you play in different 
keys, there's yet another way - a "compromise tuning" that can be used 
- albeit with lessened resonance:
Tune the four individual sympathetic strings like so:
G
A
E
D
At least two of the four strings will resonate sympathetically whenever 
you play in the key of D, G or A (just one of the sympathetics will 
resonate in the key of C).

I have a couple of nice commercially made bouzoukis & have played many 
more but because of the extra sound provided by the sympathetic strings, 
I've become especially fond of this converted 12-string.

If you don't have a 12-string guitar: not only a 12-string guitar can be thus 
converted but if you only have a regular 6-stringer, this conversion 
is well worth the effort if you ever thought you'd like to diddle with 
a bouzouki. Of course you'd only have a single string instead of two 
strings for each note but it's still a lot of fun & opens up a portal 
into the world of bouzouki/octave mandolin playing. 
String gauges for six stringer:
1st string -   .010 (bouzouki E)
2nd string - .014 (bouzouki A)
3rd string - .024W (bouzouki D)
4th string - .040W (bouzouki G)
5th string - .016 (sympathetic but occasionally played)
6th string - .012 (sympathetic but occasionally played)

Some fussy people might complain that guitar-shaped bouzoukis 
don't sound like a bouzouki -- that line of thinking doesn't 
stop numerous luthiers from building & selling a variety of 
guitar-shaped bouzoukis. Case closed.

That's about it as far as this conversion goes. 
Additional but related information is below:
---------------------------------------
*
FIGURING TOTAL STRING TENSION
Total string tension on the 12-string conversion tuned EE AA DD GG GG DD.  
I used phosphor-bronze type for all wound strings. Other sympathetic 
tunings may affect the total pull but not by much and certainly within 
the instrument's capabilities, especially when tuned a step low & 
capoed at the second fret (see below).
Total string tension on converted instrument (at regular string pitches):
.010 = E, 16.2 lbs
.010 = E, 16.2 lbs
.014 = A, 14.1 lbs
.014 = A, 14.1 lbs
.24W = D, 16.9 lbs
.012   = D, 18.5 lbs
.040W = G, 20.1 lbs
.016     = G, 14.7 lbs
.016     = G, 14.7 lbs
.016     = G, 14.7 lbs
.012     = D, 18.5 lbs
.012     = D, 18.5 lbs
TOTAL:  197.2 lbs
IN COMPARISON, 
Total tension on unconverted 12-string guitar using a set of Martin 
M190 12-string guitar strings (at regular string pitches):
.012      = E, 23.3 lbs
.012      = E, 23.3 lbs
.016      = B, 11.6 lbs
.016      = B, 11.6 lbs
.025W  = G, 32.8 lbs
.010      = G, 5.7 lbs
.032W  = D, 30.5 lbs
.014      = D, 8.3 lbs
.042W  = A, 29.9 lbs
.020      = A, 28.9 lbs
.053W   = E, 26.0 lbs
.030W   = E, 34.1 lbs
TOTAL: 263.4 lbs
---------------------------------------
LOW TUNING
A few words about tuning a 12-string guitar as well as this 
conversion a step low:
My preference for tuning any 12 string guitar is to give the 
instrument a break by tuning the whole thing a full step (2 frets) 
low and then using a "permanent" capo on the second fret. 
I've seen way too many 12 stringers with bowed-up soundboards & 
pulled-up bridges. I recommend this not only for 12 string guitars 
in general but for this bouzouki conversion as well.
To give you an idea of how much easier this is on the instrument:
A set of Martin M190 12-string guitar strings exerts a pull of 263.4 
pounds when the guitar is tuned to regular (concert) pitch. The same 
set of Martin strings exerts a pull of only 212.8 pounds when tuned 
one step lower than regular pitch & capoed at the 2nd fret.
Similarly, the strings described for this guitar-to-bouzouki conversion 
exert a pull of 197.2 pounds when tuned to regular (concert) pitch but 
the same strings exert a pull of only 156.6 pounds when tuned one step 
lower than regular pitch & capoed at the 2nd fret. 
This lower overall tuning does adversely affect the tone, but negligibly 
so in my opinion. Tuning lower & capoing is well worth doing.

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