Audemars Piguet
Royal Oak | 25829TA | tantalum & yellow gold

Open-worked perpetual calendar

Regular price


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Audemars Piguet
Royal Oak | 25829TA | tantalum & yellow gold

Open-worked perpetual calendar

Regular price


Believed to have been limited to 15 pieces, this Royal Oak Quantième Perpétuel ref. 25829TA by Audemars Piguet combines a range of distinctive features. With its exposed perpetual calendar mechanism, classic Royal Oak design and unusual two-tone case, it brings together some of the brand’s most impressive savour-faire.

A Perpetual Calendar Royal Oak

It’s been almost 50 years since the creation of the original Royal Oak. First unveiled by Audemars Piguet in 1972 and designed by Gérald Genta, who incidentally also penned the Patek Philippe Nautilus, the Royal Oak has become a cultural icon. Due to its distinctive features and its role as a pioneer for high-end luxury sports watches, its appeal has endured over the years.

Shortly after its introduction, Audemars Piguet experimented with different versions of the Royal Oak, in an attempt to bring Genta's original sketch to a wider audience, through a range of sizes and complications. The first Royal Oak to feature a perpetual calendar complication was released in 1983, as the reference 5554 - later designated the ref. 25554. At the time, the combination of the sporty, Royal Oak case and complicated perpetual calendar movement was an unusual, forward-thinking approach by the brand. It would be decades before Patek Philippe would attempt something similar with their Nautilus.

A Canvas for Experimentation

Since its introduction, Audemars Piguet has used the Royal Oak Perpetual Calendar as a canvas to experiment with different metal combinations and dial designs. From the bright Yves Klein dials to the varied two-tone cases, the collection offers a rich variety of configurations, where the manufacture has pushed the boundaries of conventional design. 

This ref. 25829TA speaks to that approach, with its unusual tantalum and yellow gold case, as well as its open-worked dial. An unusual metal, rarely ever seen in watchmaking, dark grey tantalum is highly resistant to both corrosion and wear. An Audemars Piguet advertisement from 1989 describes two-tone tantalum watches in the following words,

“Shimmering and resplendent in grey-blue, with a contrast of gold that is simply unmatched and beautiful.”

An expensive material, traditionally used in the medical and aerospace fields, the metal is also notoriously hard to work. According to Raphaël Balestra, Audemars Piguet's Museum Archivist, the machines that were used to shape tantalum needed replacing much more often, making the watches which integrated this unusual material all the more expensive to produce. Combining this with yellow gold, in a rather distinctive two-tone case, speaks to Audemars Piguet’s innovative approach at the time, reinforced by the striking open-worked dial.

The Design

This Quantième Perpétuel ref. 25829TA - with TA indicating the mixed tantalum and yellow gold case - features a transparent dial, which showcases the masterfully finished workings of the movement. With the manufacture having a long standing record in creating open-worked dials, this Royal Oak represents a more contemporary approach to this tradition. The subsidiary dials and minute track are rendered in a warm golden colour, which complements the yellow gold accents of the case. Many of the visible components are brushed and bevelled, with hand-engraved golden plates also peeking through in certain corners.

It features the "Audemars Piguet" signature in the more modern lettering, adopted by the brand towards the end of the millennium. The black feuille hands also help with the legibility of the time, despite the richness of colours and textures created by the open-worked dial.

The case is an impressive example of workmanship, with a yellow gold bezel, crown and centre links. The majority of the watch - notably the mid-case and larger links - are make out of dark grey tantalum. The contrasting metals elegantly complement each other, echoing the colours found on the dial and movement. The stainless steel clasp bears the hallmark of famed bracelet maker Gay Frères, who produced the first Oyster bracelets for Rolex, as well as integrated bracelets for the original Nautilus and Royal Oak. 

The Movement

This Royal Oak Quantième Perpétuel is powered by the AP caliber 2120/2800, derived from Jaeger-LeCoultre’s legendary ultra-thin JLC 920 calibre movement. The caliber 2120 was an initial project of Jaeger LeCoultre in 1967, funded and contributed by Audemars Piguet, and famous for its adoption by Audemars Piguet, Patek Philippe and Vacheron Constantin.

The ultra-thin automatic 2120/2802 calibre features 38 working jewels, Gyromax balance and four ruby wheels to support the full-diameter rotor, which runs on a beryllium rail for stability. The AP calibre 2120 remains the thinnest full-rotor self-winding movement in the world, considered by many as one of the most technically refined wrist-watch movements ever made. Visible through the sapphire caseback, the yellow gold rotor is hand-finished, with various decorative motifs visible.

The Set

This Royal Oak Quantième Perpétuel ref. 25829TA is accompanied by an Extract from the Archives, which confirms the watch’s case, movement and serial number. 

Brand: Audemars Piguet
Model: Royal Oak Quantième Perpétuel ref. 25829TA
Movement: mechanical automatic AP Calibre 2120/2802
Functions: perpetual calendar: month, date, day, moon-phase; hours, minutes
Features: tantalum-yellow gold case, open-worked dial
Case: 39 mm tantalum and yellow gold
Crystal: sapphire front and back 
Bracelet: tantalum and yellow gold bracelet, Gay Frères signed clasp
Year: c. 1995
Box & papers: Extract from the Archives
This Audemars Piguet Royal Oak Quantième Perpétuel ref. 25829TA is accompanied by an Extract from the Archives, which confirms the watch’s case, movement and serial number. The case and bracelet are excellently finished, with angular, beveled, polished and granular surfaces. The bracelet remains tight, with limited stretch, and has 19 links, including 3 removable ones. The 2120/2802 calibre movement of this ref. 25829TA comes with a two-year warranty from A Collected Man.

All of our pre-owned watches have undergone thorough mechanical inspections, including being ultrasonically cleaned, serviced and resealed if appropriate and tested for at least four days, to ensure they meet our highest timekeeping standards. Our pre-owned and vintage watches, unless stated otherwise, are covered by a full or a limited twenty-four month warranty. For example, due to their age, some vintage watches should not be subjected to the same conditions as when they were new. Please see our Terms & Conditions for further information. 

All of our new watches are covered by the warranty from the original manufacturer. Please contact us for further information.

We offer complimentary worldwide delivery on our watches. If ordering from overseas, delivery will depend on the value of the timepiece and the destination. All import taxes and duties are the responsibility of the buyer.

If ordering from the UK before 1 PM, your watch will be sent the same working day. The courier will depend on the value of the watch, with all watches delivered the next working day.

Please note that pre-owned goods (in the United Kingdom) are subject to a marginal rate of VAT, which can not be reclaimed. For further information, please see here

You can cancel your order without giving any reason, within 14 days from the day the watch has been delivered to you.

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