As the name suggests, Breguet's Classique Chronométrie 7727 - introduced last year and presented in an new version at BaselWord 2013 - delivers impressive precision thanks to a balance frequency of 10Hz.
The hand wound calibre 574DR is fitted with a double balance-spring, pallet lever and escape wheel, all in specially prepared silicon. The result is a regulating power equivalent to around 830 microwatts, an achievement when one considers that the regulating capacity of the best chronometers is between 300 and 400 microwatts. Despite its high frequency, the reference 7727 has a power reserve of 60 hours thanks not only to the energy stored in the two barrels, but also to the very high quality of its balance.
However, the major innovation of this Classique Chronométrie model is the use of magnetic pivots, a technology protected by at least six Breguet patents. With the magnetic pivot, Breguet not only controls the negative effects of magnetism in a watch, but also uses magnetic force to improve the pivoting, rotation and stability of the balance staff. Two endstones, incorporating powerful micro-magnets (approx. 1.3 teslas), keep the balance staff centred and self-adjusting. One of the magnets is stronger than the other to create a magnetic gradient. A magnetic flux, generated within the balance-staff induces a magnetic attraction that keeps the end of the pivot in contact with the endstone.
This way, held in an artificial gravitational force, the balance staff is unaffected by the different positions of the watch and the conditions at each pivot remain unchanged. If a shock knocks the balance staff sideways, the system acts like a pare-chute to return it to its position, except that magnetic forces re-centre the staff to regain maximum magnetic flux. The result is a balance that is insensitive to gravity, more stable and resistant to shocks. These innovations bring the reference 7727’s average rate to -1/+3 seconds a day, well within the COSC chronometer standard of -4/+6 seconds a day.
The dial of the Classique Chronométrie shows an off-centre subdial for hours and minutes, small seconds at 12 o'clock, a power-reserve indicator at 5 o'clock and a tenth-of-a-second indicator at 1 o'clock using a lightweight silicon hand.
The pare-chute shock protection is visible at 2 o'clock, both as a reminder of Breguet’s invention and to make the timepiece slimmer.
The hands are in polished steel with the Breguet open tip, while the case, available in rose or white gold, displays the typical fluting.
The 41 mm case, on a leather strap, is water resistant to 3 bar (30m) and has a sapphire-crystal back to display the movement.