Mandocello string tension
The D'Addario EJ78 is a phosphor bronze mandocello set, .022 to .074, for C2 G2 D3 A3 tuning. D'Addario lists 30.7 lb on each A string, 32.4 lb on each D, 28.9 lb on each G and 28.4 lb on each C: 240.8 lb (109.2 kg) for the eight strings, much more than a mandolin.
Tension of the D'Addario EJ78 set, string by string
Standard C G D A tuning from the 1st course (A3) on a 25″ (635 mm) scale. A and D strings calculated with the unit weights from D'Addario's tension chart (30.9 and 33.3 lb, against 30.7 and 32.4 lb on the package); G and C strings use D'Addario's published tension, since their gauges aren't listed.
| String | Note | Gauge | kg | lb |
|---|---|---|---|---|
| 1 | A3 | .022w | 14.0 | 30.9 |
| 2 | A3 | .022w | 14.0 | 30.9 |
| 3 | D3 | .034w | 15.1 | 33.3 |
| 4 | D3 | .034w | 15.1 | 33.3 |
| 5 | G2 | EJ78 · 1 | 13.1 | 28.9 |
| 6 | G2 | EJ78 · 1 | 13.1 | 28.9 |
| 7 | C2 | EJ78 · 2 | 12.9 | 28.4 |
| 8 | C2 | EJ78 · 2 | 12.9 | 28.4 |
How to use it
- The page opens with the Mandocello, the EJ78 set and standard C G D A tuning.
- Type your scale if it isn't 25″: tension grows with the square of the length.
- Edit a gauge to compare sets, such as a lighter A course or a flatwound set from another maker.
Help and explanations
The calculator starts from that set on a 25″ (635 mm) scale. Change a gauge or the scale and every string is recalculated in kg, lb or N.
The EJ78 set, course by course
All four courses are unison pairs. The A3 course uses .022 and the D3 course .034, both wound, at 30.7 and 32.4 lb per string. D'Addario's product page doesn't list the gauges of the G2 and C2 strings; by the name of the set the lowest is a .074. Their tension, 28.9 and 28.4 lb, is published, so the calculator uses it directly for those strings.
The result is an even set, between 12.9 and 14.7 kg on every string by D'Addario's figures (12.9 to 15.1 kg in the calculator), so the bass courses feel as firm under the pick as the trebles.
How the numbers are checked
Tension is T = UW × (2 × L × F)² ÷ 386.4, with unit weights from D'Addario's String Tension Specifications. On a 25″ scale the .022 comes out at 30.9 lb (+0.7 %) and the .034 at 33.3 lb (+2.8 %) against the package.
The numbers line up at about 629 mm (24.8″), so D'Addario probably calculated on a slightly shorter scale. For the G and C strings, without a published gauge, the page uses D'Addario's tension and labels them EJ78 · 1 and EJ78 · 2 instead of a gauge.
Tips
- About 240 lb on a floating bridge: change one string at a time and keep the bridge on its marks.
- Check whether your tailpiece takes loop ends or ball ends before you order a set.
- Tune each course with the mandocello tuner.
Frequently asked questions
What gauge strings does a mandocello use?
The D'Addario EJ78 runs from .022 on the A course to .074 on the C course, phosphor bronze. D'Addario publishes .022 and .034 for the A and D strings; the G and C gauges aren't listed on the product page, though the set name points to a .074 on C.
How much tension does a mandocello have?
About 241 lb (109 kg) for the EJ78 in C G D A, according to D'Addario: 30.7, 32.4, 28.9 and 28.4 lb per string on the A, D, G and C courses. On a 25″ scale the calculator gives 243 lb (110 kg).
How is a mandocello tuned?
Like a cello: C2 (65.41 Hz), G2 (98.00 Hz), D3 (146.83 Hz) and A3 (220.00 Hz), each course in unison pairs, an octave and a fifth below the mandolin.
Can I use cello strings on a mandocello?
No. Cello strings are made for a bowed instrument with a different scale, tension and end fittings. A mandocello needs a set like the EJ78 with loop or ball ends for its tailpiece.