FP Journe caliber 1505 SS

1505 SS description

Sonnerie Souveraine

The grand-strike clockwatch is the most complex of horological creations. The greatest difficulty in its construction is to achieve full clockwatch capability from the limited energy in a wristwatch, without compromising on the sound and reliability of the chime.

In this watch, a single mainspring provides enough energy for 24 hours of grand strike (96 full chimes in passing), without using the minute-repeater. The chiming functions alone use up almost 60% of the main-spring’s energy, and in silence mode without the chime, the movement is running for five days.

Constructing this movement has been a permanent search to save energy in maximising mechanical efficiency. The result is a low-tension movement with gentle mechanisms that have to be very finely adjusted to ensure unfailing chimes 35,040 times a year.