Are you a lover of perpetual calendars? Well, listen up for the Vacheron Constantin Twin Beat Perpetual is probably going to be on your wishlist when you hear what it can do.

This watch will probably be one of the top releases for SIHH 2019, and my pronouncement comes from the fact that it is simply a genius level idea, implemented exceedingly well from a functionality and convenience standpoint.

The headline feature that accounts for the words “Twin Beat” in its name, is that this watch can beat at two frequencies – a high-frequency Active mode at 36,000 vph (5Hz) and a low-frequency Standby mode 8,640 vph (1.2Hz), with the wearer able to switch between the two frequencies via the large pusher at 7 o’clock.

Why is this important? Well, how about a power reserve of 4 days in the first mode or 65 days in the second?

Turn the watch over and you will see two balance wheels in the movement that do not work as how you might expect at first glance. These two balance wheels are there not because they are meant to be resonant or to have their beat rates averaged by a differential. No, they don’t beat together. Instead they do so one at a time, at the aforementioned frequencies, which you can switch to depending on what you are doing with the watch.

The relatively high-frequency of 36,000vph (5Hz) in Active mode, is for when you wear want to wear the watch as per normal. By contrast, it is in Standby mode, when you want to set the watch aside to wear other pieces in your collection for example, and you switch the watch to the slower (1.2Hz) 8640vph frequency that things start to get interesting.

Putting a perpetual calendar watch away is the bane of people who own them, and it is something you have to experience to realize. Anxieties accrue when you do so, especially, if you’re the type of person who likes your indications to be correct when you wear the watch. The reason why is simple – most times when you pick up a perpetual calendar to wear again, the power reserve would have worn down. It is then a rather tedious process to adjust the watch, either with pushers, for just advancing the time, through the days that you didn’t wear it, which can sometimes feel like the watch is punishing you for every day that you are away from it. Some perpetual calendar owners that I see, forgo the tedium, and instead just set the correct time only and move on with their lives.

The Twin Beat Perpetual however does away the tedium or the incorrect calendar indications, by giving you up to an amazing 65 days in Standby mode to keep all your calendar indications correct and thus lowering your level of anxiety for when you next want to wear the watch again. And how the watch achieves this feat is via a redesigned jumping mechanism, with a sprung dual gear compound system that requires 4 times less torque than conventional jumping displays. Vacheron Constantin says that even at midnight on New Year’s Eve when all three indications need to jump instantaneously, the effect on the amplitude on the active balance (and thus accuracy) is negligible.

This attitude to keeping accuracy also accounts for the patent-pending mechanical system that enables instantaneous switching between two two balance wheels. These operate on an all-or-nothing principle, that allows only one balance to oscillate at a time, with no delay during the switch, and thus no loss of time.

In order to enable this watch to do what it can do, Vacheron Constantin had to come up with a number of new innovations for the new 480 component calibre 3610 QP. The first, a new hairspring created specifically for the needs of the highly sensitive Standby balance (1.2Hz, 8,640vph), which has cross-sectional dimensions of 0.0774mm by 0.0159mm, comparable to human hair. Compared to the Active balance (5Hz, 36,000vph), the hairspring of the Standby balance is nearly four times smaller in cross section and exponentially more delicate.

As well, the watch has hands that can read timekeeping information from two separate gear trains and their associated balance wheels via a gear differential. Finally, there is another differential that is mounted on the barrel that has the dual function of winding the mainspring and also reducing the mainspring torque as it is directed towards the more delicate hairspring of the Standby mode balance.

With all these innovations, its an impressive feat that the calibre itself is only 6 mm in height and 32 mm in diameter, and all mounted in an immensely wearable 42mm case. And it is certainly going to be quite fun and interactive to switch the balance wheels, and to see them work alternately.

Looks wise, the watch has a design that departs from the overtly classical nature of Vacheron Constantin, and adds a little more of a technical flavour in line with the character of the watch. The power reserve indicator up top at 12 o’clock contains a red scale for Standby mode and black scale for Active mode and is colour coded to the mode selector indication at 9 o’clock. Added to this, the date and month dials that form the lower half of the dial are mounted on sapphire disks, that give a view into the parts that make them work.

It’s nice to see something like this from Vacheron Constantin, since their recent forays collections have been more lifestyle oriented than technical. This watch does demonstrate convincingly however, the breadth of savoir-faire the brand is capable of.

The Vacheron Constantin Twin Beat Perpetual is available exclusively from Vacheron Constantin boutiques.

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