Resonance is a striking phenomenon in physics. Through resonance, a vibration in one object can cause an equal vibration in another, nearby object. For instance, strike a tuning fork, bring a second tuning fork next to it, and it will begin to vibrate in sympathy. Two oscillating bodies in close proximity, therefore, influence each other and eventually synchronize. Christiaan Huygens foresaw resonance could be applied to watchmaking with pendulums swinging in sympathy. Antide Janvier and Abraham-Louis Breguet made it happen. The modern history of resonance started with François-Paul Journe, who crafted the first wristwatch taking advantage of the synchronicity of two oscillators. Released to celebrate the 20th anniversary of the model, the newest version of the Chronomètre à Résonance is far more technically advanced and… simply superb. Let’s take a closer look.
Above: F.P. Journe Pocket watch uncased movement with resonant oscillators (1983) – the first wristwatch prototype (1998)
François-Paul Journe’s first work with resonance was inside a pocket watch movement dating back to1983 and in 2000 he presented the first “résonance” wristwatch under the “souscription” system. The original Chronomètre à Résonance dual movement was designed with two sets of independent barrels, gear trains and regulators. These are laid out independently and symmetrically. One of the two balance cocks swivels in order to finely adjust the distance between the two oscillators so that they will function “sympathetically” to achieve greater chronometric precision. Since then, the model has been released in numerous versions. And it has turned into a genuine horological icon… Phillips recently auctioned one of these rare subscription Chronomètres à Résonance for over CHF 1,000,000.
F.P. Journe now celebrates the 20th anniversary of the model with a splendid and more mechanically complex version. From a technical perspective, the idea is always to place the two balance wheels in close proximity so that they influence each other and beat in sympathy. Yet, with the new calibre 1520, thanks to a differential gear, one single barrel now drives two gear trains to provide equal power to the each of the two regulators. Additionally, each gear train is fitted with a one-second remontoir d’égalité – another signature function of F.P. Journe.
A remontoir is a mechanism consisting of a secondary spring to power the regulator. It is rewound periodically by the mainspring and isolates the escapement and oscillator from the varying torque of the barrel. The two remontoirs of the calibre 1520 maintain isochronous oscillations resulting in greater regularity and precision throughout 28 hours. If the movement’s power reserve is given for 42 hours, the remontoirs need a minimum amount of force to function. So, you would ideally need to wind your watch every day. The whole idea of this new movement architecture with twin gear trains and twin remontoirs d’égalité is to obtain similar, regular amplitudes for the two oscillators, in order to enhance the phenomenon of resonance. If you want these to beat in sympathy, they should run at the same pace…
This new calibre 1520 is presented in a redesigned Chronomètre à Résonance case, available in polished platinum or 6N pink gold, and in a 40mm or 42mm diameter. A more elegant, ergonomic and practical design compared to the previous versions, the two crowns are now positioned at 2 and 4 o’clock (versus 12 and 4 o’clock respectively). The upper crown allows you to wind and set the two time indications: clockwise for the left dial and anticlockwise for the right dial. The lower crown is used to reset and synchronize the second hands. On the wrist, the watch is supremely elegant and wears comfortably thanks to the elongated lugs and the relatively slim case profile – especially the more compact 40mm diameter, seen here on the rose gold model.
In characteristic F.P. Journe style, the dial comes in 18k white gold or 18k 6N pink gold. The subdials are whitened solid silver, guilloched with a clou de Paris pattern. The time is indicated on 24h on the left dial and 12 hours on the right dial. These are independent and can be used to display two different time zones. The power reserve is indicated at 12 o’clock. Last, an opening at the centre of the dial shows the movement differential gear. The hands are blued steel.
Flip the watch over and you are granted an unimpeded view of the magnificent hand-wound movement. Comprising no fewer than 378 components, the calibre 1520 looks technically complex. The symmetry and balance of its architecture are superb. And as always with F.P. Journe, the finishing is spectacular. In characteristic style, the bridges and main plate are fashioned out of solid 6N rose gold. These are decorated with perlage and beautifully applied Geneva stripes. The flawless screw heads are polished and bevelled with chamfered slots.
The new F.P. Journe Chronomètre à Résonance is worn on an alligator leather strap with alligator lining. It is secured by a gold or platinum pin buckle. A quick-release spring bar system allows you to change the strap easily. Gold or platinum bracelets are also available. The first pieces have just been delivered with long retail backorders. Price is set at CHF 101,400 in rose gold and CHF 105,000 in platinum.
For more information, please visit www.fpjourne.com.