To implement the grande sonnerie as envisioned, Patek Philippe developed a new movement as a spin-off of the caliber 300 of the Grandmaster Chime. Given its 703 parts, the caliber GS 36-750 PS IRM is remarkably compact for such a complex mechanism (diameter: 37 mm; height: 7.5 mm).
For the Grande Sonnerie, Patek Philippe opted for three classic gongs – low, medium, high. This technical option requires more energy than systems with two gongs. It also complicates the watchmaker’s work when tuning each gong until all three create the legendary “Patek Philippe sound” so coveted by connoisseurs. Attached to the movement, the three gongs must not touch one another nor other parts of the case or movement despite the compact space in which they hover.
The new caliber GS 36-750 PS IRM can be admired through the sapphire-crystal case back of the Ref. 6301P Grande Sonnerie. The centrifugal governor that regulates the speed of the time strikes is decorated with exquisitely smoothed and polished finishes that are now visible to the observer.