Audemars Piguet kicks off its 150th anniversary in a big way with an all-new perpetual calendar movement, the Audemars Piguet Calibre 7138. Making its debut in both the Code 11.59 and Royal Oak, the cal. 7138 is a landmark in traditional perpetual calendars. In fact, the movement is perhaps the most sophisticated and user-friendly perpetual calendar from an establishment brand.

The calendar relies on the classic “grand lever” mechanism that’s been reinvented in an ultra-thin manner, but more importantly, the cal. 7138 employs an ingenious and innovative setting mechanism. Consequently, it is impressively intuitive and also foolproof. All the calendar indications are set via the crown, and the movement can’t be broken by setting it at the wrong time. Together, these features mark the cal. 7138 out as one of the most notable perpetual calendar movements on the market today.

The cal. 7138 debuts in the Code 11.59 (left) and Royal Oak. Image – Audemars Piguet

Initial thoughts

The perpetual calendar has long been a key part of the history of Audemars Piguet (AP), especially after the bestselling ref. 5548 was launched in 1978. So a brand-new perpetual calendar for its 150th anniversary is fitting. At the same time, the calibre illustrates AP’s tremendous advances as a vertically integrated, industrial-haute horlogerie manufacture that has developed an splendid stable of in-house calibres in a relatively short period of time.

The irony is that the cal. 7138 is almost identical to its predecessors in layout, save for some transposed indication. It looks virtually identical at a distance, and retain the same four-register layout. But the cal. 7138 is milestone in modern-day perpetual calendars, particularly amongst large-scale, establishment brands.

The red arch on the 24-hour counter indicates the no-correction period

The usability of the movement is all the more pronounced because the calendar layout looks so traditional; the four-register look is synonymous with multiple pushers and a troublesome stylus (or even worse, a toothpick).

The cal. 7138 is wonderfully easy to set, with every single calendar indicator set via the four position crown (or maybe three-and-a-half). Add to that the “no-correction” time where the calendar can’t be set – but cannot be damaged even if it is – and the movement is pleasingly foolproof.

The case is free of pushers, enhancing aesthetics but also water resistance, giving the Royal Oak a 50m rating

But the cal. 7138 is not just a clever setting mechanism tacked on top of an ordinary calendar. The movement employs the condensed, flattened calendar mechanism pioneered by the Royal Oak Perpetual Calendar Ultra-Thin (and before that the RD#2), while the base movement is the cal. 7121 found in the latest-generation Royal Oak “Jumbo” ref. 16202. The combination keeps the cal. 7138 a slim 4.1 mm high.

Best of all, the new models equipped with the cal. 7138 retail for the same as their immediate predecessors with the outgoing cal. 5134. The sums are still large – the steel Royal Oak retails for CHF88,000 before taxes – but given the strengths of the cal. 7138, the price is more easily rationalised and maybe even a value proposition.

The Code 11.59 sports an appealing concentric guilloche dial

Classical but clever

The foundation of the cal. 7138 is one of AP’s latest-generation movements, the cal. 7121 of the Royal Oak “Jumbo”. Just 3.2 mm high, the cal. 7121 in itself is a sophisticated, slim movement that is smartly executed in several ways.

With the perpetual on top, it becomes the cal. 7138, which is easily one of the most interesting perpetual calendar movements of recent years. The cal. 7138 is best described as a fusion of classical calendar concepts with intelligent, contemporary engineering.

The basic principles of the cal. 7138 are classical. It employs a “grand lever” and 48-month cam, like almost all perpetual calendars before it. This contrasts with the radically unorthodox calendar movements, like the MB&F LM Perpetual, which do away with the “grand lever” and associated parts.

Although the calendar of the cal. 7138 is fundamentally classical, it has been implemented in a thoroughly novel manner – the calendar itself boasts five patents pending: two separate patents for the crown setting system, two patents regarding the flat perpetual calendar construction, and one patent for the progressive stepping day wheel.

Some of these innovations stem from the movement found in the RD#2. This speaks to AP’s development process works, where new technologies are first rolled out in concept watches then slowly perfected at scale and brought to regular production movements.

Brilliantly user-friendly

The cal. 7138 was conceived to address some of the main problems inherent in classic perpetual calendars. One is the need for asymmetric case pushers to set the calendars. These recessed pushers break the lines of the case, affect water resistance, and often cause much hassle during setting. A practical example of that: using a toothpick or other sharp object to set the calendar, slipping, and then scratching the case.

No pushers anywhere

The cal. 7138 is fully set through the crown, which has three positions but four setting stages. When flush with the case in the first position, the crown winds the movement as is convention.

Pulled out in the second position, the crown adjusts the date and month. Pulled out to the third position, when the crown is furthest from the case, hacks the movement and allows for time setting bidirectionally. 

The clever part is returning the crown to the second position engages another setting mechanism. In this returned-second position, the crown controls the day and week pointers (crown turned clockwise), along with the moon phase (counter-clockwise).

This innovative crown cycle allows the user to set a full perpetual calendar with six separate indications through a three-position crown, like the ones found in timepieces with a simple date display. 

The Code 11.59 features a smoked, pale blue dial

There is also a discrete 24-hour indicator, which has a red border indicating the “no-setting” period when it is best not to set the calendar. But it is not fatal: if the wearer choses to fiddle with the calendar nevertheless, the date might not change, but the calendar mechanism can’t be damaged or jammed.

And to go with the clever setting mechanism, the calendar display itself is intuitive.

The firsts for each – day of the week, date of the month, week of the year, month of the year and year of the leap cycle – are all located at the 12 o’clock position in each register, making for a cohesive and logical display.

The Royal Oak version in sand gold

Technical accomplishments

The cal. 7138 is a good example of innovative contemporary watchmaking, blending classic systems with a modern engineering approach. The all-crown setting system is a great feat, which improves and eases the owner – timepiece operation, but the calendar construction itself is even more interesting. 

Perpetual calendars are notorious for being complicated and layered mechanisms, which add to a movement’s part count and thickness. The calendar complication found in the cal. 7138 works on one single level, bringing down the movement’s thickness drastically — just 4.1 mm in total. 

The calendar mechanism of the cal. 7138. Image – Audemars Piguet

At its core, the system is based off the 48-month cam calendar mechanism that is well known to watchmakers. But in the cal. 7138, the concept has been simplified, with the various multi-level assemblies merged into single-layered parts. In traditional constructions, the perpetual calendar works alone is made up of two or three layers. 

The calendar mechanism of the cal. 7138. Image – Audemars Piguet

A particularly clever detail is the day wheel, which has teeth that are not identical. Some teeth have larger steps between them, allowing the date wheel to move slightly more when indexed to new date. The date wheel makes smaller steps for single-digit dates and jumps a little wider for double-digit dates.

This is reflected on the date register, where single-digit dates are arranged more tightly, which leaves more space for double digit dates to be displayed more clearly. This allows for a more generously spaced date display, improving legibility.

Conventional date indicators, on the other hand, usually cram double-digit dates in the same space as single-digit dates, making for poor readability.

Installing the moon phase disc. – Audemars Piguet

Anniversary editions

The inventive movement will debut in three models — two Royal Oak and one Code 11.59. The Royal Oak versions are in steel and sand gold respectively, while the Code 11.59 is in white gold. All are regular production.

Additional, each model will be available as an 150-piece limited edition for the anniversary, featuring an italic “Audemars Piguet” signature modelled on the historical brand logo as the distinguishing factor. These anniversary editions cost CHF3,000 more than the standard versions.

The 150th anniversary signature. Image – Audemars Piguet

Key facts and price

Code 11.59 by Audemars Piguet Selfwinding Perpetual Calendar 41 mm
Ref. 26494BC.OO.D350KB.01 (regular production)
Ref. 26494BC.OO.D350KB.02 (150th anniversary edition)

Diameter: 41 mm
Height: 10.6 mm
Material: 18k white gold
Crystal: Sapphire
Water-resistance: 30 m

Movement: Cal. 7138
Functions: Hours, minutes, and perpetual calendar
Winding: Automatic
Frequency: 28,800 beats per hour (4 Hz)
Power reserve: 55 hours

Strap: Rubber strap with white gold clasp

Limited Edition: Anniversary edition limited to 150 pieces, otherwise regular production
Availability: At AP boutiques and AP houses
Price: CHF88,000; CHF91,000 for anniversary edition (prices exclude taxes)

Audemars Piguet Royal Oak Selfwinding Perpetual Calendar 41 mm
Ref. 26674ST.OO.1320ST.01 (steel, regular production)
Ref. 26674ST.OO.1320ST.02 (steel, 150th anniversary edition)
Ref. 26674SG.OO.1320SG.01 (sand gold, regular production)
Ref. 26674SG.OO.1320SG.02 (sand gold, 150th anniversary edition)

Diameter: 41 mm
Height: 9.5 mm
Material: Steel or 18k sand gold
Crystal: Sapphire
Water-resistance: 50 m

Movement: Cal. 7138
Functions: Hours, minutes, and perpetual calendar
Winding: Automatic
Frequency: 28,800 beats per hour (4 Hz)
Power reserve: 55 hours

Strap: Matching bracelet

Limited Edition: Anniversary editions limited to 150 pieces, otherwise regular production
Availability: At AP boutiques and AP houses
Price: CHF88,000 in steel, CHF91,000 for anniversary edition; and CHF130,000 in sand gold, CHF133,000 for anniversary edition (prices exclude taxes)

For more, visit audemarspiguet.com.