In addition to the extraordinary Grande Sonnerie function, the Patek Philippe Ref. 6301P grand complication watch also incorporates a petite sonnerie (that does not strike the quarter hours), a minute repeater (that strikes on demand), and a patented jumping subsidiary seconds. It is Geneva manufacture’s first wristwatch that presents the grande sonnerie as the epitome of horological complications in its purest form, complemented with a petite sonnerie and a minute repeater.
For this grand complication timepiece, 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).
One of the traditionally greatest difficulties for the engineers of grande sonneries is mastering energy flows and power reserves. Unlike in minute repeaters which must be triggered on demand by actuating a slide or a pusher, the grande sonnerie needs to have sufficient reserve power to automatically sound the required number of time strikes with uniform acoustic quality.
To address this challenge, Patek Philippe endowed the caliber GS 36-750 PS IRM with two tandem-connected twin mainspring barrels, one for the going train and the other for the chiming mechanism. This configuration delivers a power reserve of 72 hours for the movement and of 24 hours for the strikework.
The 24-hour power reserve for the strikework allows the watch to strike the full hours and the quarter hours during an entire day and thanks to a uniform torque characteristic to assure optimized sound intensity. The two twin mainspring barrels are wound with the crown pushed in and rotated clockwise to wind the going train and counter-clockwise to wind the strikework. The four mainsprings feature slip bridles to avoid over-tensioning.
As regards the strikework, 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. Three hammers of identical size and mass guarantee a uniform strike for all three pitches. The selection of platinum as the case material also presented a challenge because it is difficult to master acoustically and requires Patek Philippe know-how that at the manufacture is handed down from one generation to the next.
The hours are struck on a low-pitched gong, the quarter hours with a three-strike high-low-medium sequence. The melody for the first quarter hour (15 minutes) sounds once, for the second quarter hour (30 minutes) twice and for the third quarter hour (45 minutes) three times. Each quarter-hour sequence is automatically preceded by the number of elapsed hours, and followed by the number of quarter hours.
Thanks to the energy stored in the twin mainspring barrel of the strikework, this adds up to an impressive total of 1056 strikes in 24 hours. The owner can also select the strikework mode petite sonnerie; it strikes the full hours but omits the repetition of the hours when striking the quarter hours. In the silence mode, the automatic time strike is switched off altogether.
The selection of the strikework mode is performed with a slide switch in the caseband at 6 o’clock. The petite sonnerie mode is on the left adjoining the grande sonnerie mode in the middle and silence on the right. This special feature is the subject of a patent that was already developed for the Patek Philippe Grandmaster Chime and describes a mechanism that enables the selection and activation of the strike mode with a single slide switch.
Formerly, two switches were needed to execute these steps. Another patent, also developed for the Grandmaster Chime, allows the complete isolation of the grande sonnerie in the silence mode, eliminating power consumption.
On request, the minute repeater can be triggered by pressing the pusher in the crown at 3 o’clock. In response, it strikes the number of hours with low tones, the quarters with three-strike sequences (as in the grande sonnerie mode), and, on the higher-pitched gong, the number of minutes that have elapsed since the last quarter hour. The minute repeater can be triggered at any time, even if the slide is set to the silence mode.
When they reworked the caliber 300 from the Patek Philippe Grandmaster Chime, the engineers and designers at the manufacture added a small jumping seconds display, which was never done with a grande sonnerie.
Inspired by the four patents of the 175th-anniversary model, the Ref. 5275 Chiming Jump Hour, they endowed the new Ref. 6301P with an innovative jumping seconds mechanism. Its system does not rely on jumper springs as usual but instead with wheels and a release lever that instantaneously unblocks the wheel train every second, making energy consumption easier to regulate and control.
Thus, the new Ref. 6301P chiming watch presents a novel face characterized by the subsidiary seconds hand at 6 o’clock. With the blink of an eye, it jumps along the railway track minute scale from one second to the next, recalling the regulator clocks that were used in old watchmaking ateliers to synchronize the time. The new Ref. 6301P also benefits from the entire experience and the latest insights gained in the design and production of the commemorative watches crafted on the occasion of Patek Philippe’s 175th anniversary.
The new caliber GS 36-750 PS IRM – it can be admired through the sapphire-crystal case back – fulfills all the strict requirements of the Patek Philippe Seal. This applies to the technical parameters (rate accuracy, dependability) and to the finissage and attractive architecture of the individual components.
Special attention was devoted to the design of the movement bridges, especially the barrel bridge (a key element of grande sonneries) and the transversal balance cock (balance bridge), a Patek Philippe rarity that assures a secure seat and pleasing visual proportions. Connoisseurs will discover many other aesthetic details, including the many re-entrant angles that are very difficult to polish.
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. This spectacular movement is rounded out with a Gyromax® balance, the Spiromax® balance spring in Silinvar®, the three gongs coiled around the movement, and their respective hammers.
The antireflective sapphire-crystal back positioned very close to the movement offers a fascinating glimpse into a micromechanical realm. It can be replaced with a solid platinum back that is delivered with the watch.
The platinum case, inspired by the Ref. 5370 split-seconds chronograph presented in 2015, expresses subtlety and balance in its curves and rounded contours, with the concave bezel for a perfect transition from the slightly cambered sapphire-crystal glass and the countersunk satin-finished case flanks. Like all Patek Philippe platinum cases, it sports a small diamond set in this instance at 12 o’clock because the usual 6 o’clock position is occupied by the slide switch for selecting the strikework mode.
Patek Philippe has leveraged its skills with respect to artisanship and rare handcrafts, notably on the black grand feu enamel dial with the “glacé” finish, applied Breguet numerals, and leaf-shaped hands in luminescent white gold. The slightly slanted Breguet numerals add a dynamic touch to the classic yet contemporary face.
The displays for the hours, minutes, and subsidiary seconds at 6 o’clock are well proportioned alongside two power-reserve indicators for the movement and the strikework at 3 and 9 o’clock with semicircular scales identified with the inscriptions MOUVEMENT and SONNERIE.
The timepiece is worn on a hand-stitched shiny black Alligator strap with square scales and a fold-over clasp.
Model: Patek Philippe Ref. 6301P Grande Sonnerie
The 6 complications of the new Ref. 6301P Grande Sonnerie
1. Grande sonnerie
2. Petite sonnerie
3. Minute repeater
4. Movement power-reserve indicator
5. Strikework power-reserve indicator
6. Jumping seconds
• Isolation of the grande sonnerie in the silence mode (Patent CH 704 950 B1): In the silence mode, this mechanism totally isolates the grande sonnerie from the power flow and eliminates energy consumption.
• Selection of the strikework mode (Patent CH 706 080 B1): This mechanism enables the selection of the strikework mode (petite sonnerie, grande sonnerie, silence) with a single lever and a single slide switch. Two slide switches were formerly required for this operation.
• Jumping display with a jumping seconds wheel (Patent CH 707 181 A2): This innovative mechanism for jumping displays does not require springs and levers but instead uses wheels and a release lever that instantaneously unblocks the wheel train every second, and features a coiled return spring as the only power element. The advantage of this system is that it makes energy consumption easier to regulate and control.
Caliber GS 36-750 PS IRM
Manually wound mechanical movement
Grande and petite sonnerie, minute repeater on 3 gongs
Strikework mode indicator (petite sonnerie, grande sonnerie, silence)
Power-reserve indicators for movement and strikework
Diameter: 37 mm
Height: 7.5 mm
Number of parts: 703
Number of jewels: 95
Movement power reserve: 72 hours
Strikework power reserve: 24 hours
Frequency: 25,200 semi-oscillations per hour (3.5 Hz)
Balance spring: Spiromax® (in Silinvar®)
• Pushed home: Winding the movement (clockwise), winding the strikework (counterclockwise)
• Pulled out: To set the time
• Center hour and minute hands
• Jumping subsidiary seconds at 6 o’clock
• Movement power reserve at 9 o’clock
• Strikework power reserve at 3 o’clock
• Pusher in the crown at 3 o’clock triggers the minute repeater
• Side switch at 6 o’clock selects the strikework mode (petite sonnerie, grande sonnerie, silence)
Patek Philippe Seal
Platinum 950 with a flawless Top Wesselton diamond between the lugs at 12 o’clock
Not water-resistant, protected against moisture and dust
Sapphire-crystal case back and interchangeable solid back
Case dimensions: Diameter: 44.8 mm
18K gold, black grand feu enamel with “glacé” finish
Applied Breguet numerals in 18K white gold
Leaf-shaped hour and minute hands in 18K white gold with luminous coating
Subsidiary seconds at 6 o’clock with “dague” type hand in white gold, printed railway track seconds scale with luminous 10-second markers
Printed railway track minute scale with luminous 5-minute markers
“Cheveu” type hands in white gold for the power-reserve indicators for the movement and the strike-work
Hand-stitched alligator leather with large square scales, shiny black, platinum foldover clasp