Converting my B-25 3/4 to a requinto guitar?

[hillin]

I have a little Gibson B-25 3/4 (reissue) guitar, a very cute one with only 22 3/4" scale length. Typically I use medium gauge strings to balance the short scale, but recently and idea has come across my mind: why not convert it to a requinto guitar?

By borrowing the term "requinto" from nylon-stringed guitars, I mean a steel-stringed guitar with higher register of pitch, say, tuning to a fourth higher than a standard guitar (A2-A4).

I do have several (scale length, size and tuning-wise) standard guitars, so I can spare this one to have some more variances in my armory.

I'm really curious, has anyone done this before?


Here is some boring maths:

I found this formula to calculate string tension:
(from http://www.daddario.com/upload/tension_chart_13934.pdf)

T = (UW x (2 x L x F)²) / 386.4
where
UW- Unit Weight expressed in pounds per linear inch (lb/in).
L- Scale Length. This is the vibrating length of the string. This is determined by
measuring the distance from the nut to the bridge of the instrument in inches (in).
F- Frequency or pitch. This is the pitch at which you will be tuning the string
expressed in cycles per second (Hertz)

So the idea is, modify F and M to keep T in a safe range:

• because a requinto guitar is tuned a fourth higher in pitch, the F is increased to 2^(5/12) = 1.335 times
• and the scale length of this guitar is only 22.75/25.5 = 0.892 times of a standard 25.5" guitar, the L is reduced to 0.892 times
• so we have to reduce UM to 1/(0.892 x 1.335)² = 1/1.418 to balance the tension
• or we have to reduce the total mass of all strings to 1/(1.418 / 0.892) = 1/1.590 to balance the tension

That means to achieve a similar tension as on a standard guitar with 25.5" scale length and medium gauge strings, this requinto guitar needs a set of custom gauge strings, around 0.009-0.042.

[drive-south]

Thats still a bit long for tuning A-A.

Have you considered Nashville tuning for this little Gibby? This involves using the octave strings from a 12 string set.

[hillin]

Originally Posted by drive-south

Thats still a bit long for tuning A-A.

Have you considered Nashville tuning for this little Gibby? This involves using the octave strings from a 12 string set.

Wow TIL about Nashville tuning! Thank you! I will definitely give it a shot - it's a great idea to apply such a tuning on a guitar like my B-25 3/4, whose shiny and sweet treble is adorable but sometimes you'd like to avoid the boxy bottom end.

Speaking of A-A, what would you expect might happen if I do it on this guitar? A set of 0.009 gauge strings seems doable.

[drive-south]

Tacoma Papoose is 19.1" scale and tuned A-A with light gage strings. You may be able to tune the Gibson G-G with lights or custom lights. If you play open tunings such as open G you might experiment with this guitar in various tunings and string gages. If you're not interested in open tunings I would go Nashville tuning. That guitar would be ideal for Nashville. You can buy strings made specifically for Nashville.

[Wade Hampton]

Give it a try, see how well the guitar handles it. You’re going to want to keep an eye on the neck, obviously, but watch how the bridge, top and overall neck set geometry respond, as well.

Personally, I think it’ll be just fine, provided that you use extra light strings. Those little Gibsons tend to be fairly robust.


Wade Hampton Miller

[hillin]

Originally Posted by drive-south

Tacoma Papoose is 19.1" scale and tuned A-A with light gage strings. You may be able to tune the Gibson G-G with lights or custom lights. If you play open tunings such as open G you might experiment with this guitar in various tunings and string gages. If you're not interested in open tunings I would go Nashville tuning. That guitar would be ideal for Nashville. You can buy strings made specifically for Nashville.

Yes, Nashville tuning sounds promising, but it seems I have to make a new saddle for it. I'll definitely give it a shot sometime.

Originally Posted by Wade Hampton

Give it a try, see how well the guitar handles it. You’re going to want to keep an eye on the neck, obviously, but watch how the bridge, top and overall neck set geometry respond, as well.

Personally, I think it’ll be just fine, provided that you use extra light strings. Those little Gibsons tend to be fairly robust.


Wade Hampton Miller

Thanks Wade. One thing I'm concerning is whether the extra-light strings can bear this kind of tension, because I believe the thinner the string is, the less tension it can withstand.

[hillin]

After some more in-depth research, I decided to try D'addario's EJ41 set. This extra-extra light (009-045) 12-string set is a great stone for two birds: I can use the wounded strings to try the requinto setup, and the drone strings for Nashville tuning. Just ordered, waiting to try

[Misifus]

Originally Posted by hillin

Thanks Wade. One thing I'm concerning is whether the extra-light strings can bear this kind of tension, because I believe the thinner the string is, the less tension it can withstand.

Actually, lighter gauge strings can tolerate being tuned higher because of their lighter mass. You would do well to use D'Addario's string tension calculator to calculate the tension of each of the six strings at the tuning you propose to use. Be sure that the resulting tension is not too much higher than standard tuning at full scale length (25.4).