This thoroughly skeletonised and open work variation of the original Audemars Piguet Quantième Perpétuel*, originally retailed in Palermo, Italy in 1990. The reference 25668, with a 36mm yellow gold case, showcases the intricate inner workings of this most hallowed of complications. It is powered by the self-winding calibre 2120, which isn’t just skeletonised but lavishly hand engraved. It is understood that only 94 examples of this reference were produced in yellow gold.
Worth Reading
One of a family of references that descended from the original ultra-thin Quantième Perpétuel 5548, the reference 25668 was created in the late 1980s, following the earlier 25558, with production continuing till the middle of the 1990s. It retains the original layout designed by Jacqueline Dimier – the perpetual calendar indications are laid out in an intuitive fashion, with the day and date on the same plane at 9 and 3 o’clock respectively. The months are displayed at 12 o’clock, while the moonphase indication is at 6 o’clock, with a semi-circular graduated scale for the indication.
The original owner purchased this watch in Palermo in 1990 and held on to it for decades. It is a relatively early example, as evidenced by the small font on the brand mark. It wears a slim, classical yellow gold case with a pronounced stepped bezel, a horizontally satinated midcase, and a display caseback with a rim on which are engraved details of the reference, brand mark, country of origin, and serial number. As is typical of the reference, while the correctors for the annual calendar complications are located on the midcase, the caseback features prominent bulges to accommodate their circular form. These are however not as prominent as the earlier cases seen in the 25558, which were upgraded for the 25668. The left flank also wears the crisp, precious metal hallmarks. The lugs are short and straight, gently tapering down. They are 20mm apart and wear curved bars with a black alligator grained strap from the brand. The strap is secured by a signed yellow gold pin buckle.
The dial furniture includes a cream-coloured chemin de fer minutes track with black printing. The subdials are framed by rims of the same warm shade with black printed scales. The moonphase complication is a golden disc, blued to a brilliant shade, save for the moons and the stars. Half of the register is taken up by a transparent screen on which is printed the branding in a simple, small san serif font. The hours and minutes hands are golden, while the ones plying the calendar complications are heat blued.
The watch is powered by the self-winding calibre 2120, an ultra-thin movement that was derived from Jaeger-LeCoultre’s famed calibre 920. The ebauche resulted from a 1967 project at Jaeger LeCoultre, that Audemars Piguet funded and contributed to. The resulting calibre 920 was adopted by Audemars Piguet, Patek Philippe, and Vacheron Constantin. In its golden, skeletonised iteration here, it is especially jewel-like to the eye. Visible through the sapphire caseback, almost all components have not just been skeletonised to their basic structures, but they have been further embellished by hand engraving. The solid gold rotor also gets this skeletonised treatment, creating a stylised “AP”. The rim wears a beautiful floral motif repeated remarkably consistently. On the rotor are hand etched details such as the brand mark, country of origin, jewel count, and the five positions the movement has been adjusted for.
It is understood that 205 examples of the reference 25668 were produced over a decade long run, with 94 of them in yellow gold.
The watch comes with its outer box, a leather-clad watch winder from Audemars Piguet as well as an Italian user manual and movement paperwork also in Italian, denoting the unique movement number of the watch and the date in which the calendar was set before leaving the workshop. It is a remarkable example of one of the most sought-after iterations of this reference.
Specifications
Closer look
Brand: | Audemars Piguet |
Model: | Quantième Perpétuel Skeleton ref. 25668BA |
Movement: | automatic calibre 2120 |
Functions: | perpetual calendar (month, date, day, moonphase, hours, minutes) |
Features: | skeletonised dial and movement, skeletonised rotor, display back |
Case material: | yellow gold |
Case diameter: | 36mm |
Case thickness: |
8mm |
Lug-to-lug: |
38mm |
Crystal: | sapphire front & back |
Strap: | burgundy saffiano strap from our own collection, Audemars Piguet black alligator strap, Audemars Piguet yellow gold pin buckle |
Lug width: | 20 x 16mm (curved) |
Year: | 1990 |
Accompanying materials: | Audemars Piguet outer cardboard box, instructions booklet, movement paperwork |
Condition
This Audemars Piguet Quantième Perpétuel Skeleton 25668 is in very good overall condition. The case and lugs show signs of wear and superficial marks consistent with moderate wear over time. More specifically throughout the bezel and lower right lug. Oxidation and warm patina are present throughout the case, lugs, caseback, and buckle. The dial, hands, and movement are free from any signs of imperfections and have been well preserved. The hallmarks on the left side of the mid-case and engravings on the case-back rim are extremely sharp and well defined.
Warranty
The watch comes with a two-year warranty from A Collected Man, alongside a lifetime guarantee of authenticity.
We stand by the quality of all of our pre-owned watches and mechanical objects. If something goes wrong, we’ll always strive to remedy the situation in a timely manner and to the best of our ability. The satisfaction and trust of our clients is of the highest importance, to everyone at A Collected Man.
All of our pre-owned watches have undergone thorough, non-invasive mechanical inspections and have been serviced, if appropriate, to ensure that they meet our highest standards of timekeeping and functionality.
Our pre-owned watches, unless stated otherwise, are covered by either a full or a limited twenty-four month warranty. This excludes any damage sustained due to improper use or accident. Due to their age, some pre-owned watches should not be subjected to the same conditions as when new.
Any of our pre-owned watches which have been serviced by their respective manufacturer, will carry the manufacturer’s servicing guarantee. This is separate and supersedes, the standard warranty offered by A Collected Man. Please see our Terms & Conditions for further information. You can write to us directly at enquiries@acollectedman.com, for further clarification.
A Collected Man is also an authorised retailer for a number of watchmaking brands. These watches are covered by the warranty from the original manufacturer.
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.
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Leap Forwards of Perpetual Calendar
The first perpetual calendar pocket watch was invented by Thomas Mudge in 1762, yet it wouldn’t be until 1925 when Patek Philippe produced the first perpetual calendar wristwatch. That’s how hard it is to miniaturise this complication, just so that its wearer isn’t thrown out of sync for a moment every four years.




Certainly, the complexity of this complication isn’t just about scale. It’s about energy. If a chronograph requires a lot of energy just to move those three extra hands, now imagine the energy demands of a watch whose entire mechanism needs to be constantly running, even while it appears to be doing not much at all. This requires minimal friction, minimal weight and whatever else can be done to conserve energy.
All of which begs the question, if perpetual calendars can not only be challenging to make, but even to own, what quite is their appeal? Michael Friedman, who holds the fantastic title of ‘head of complications’ at Audemars Piguet – makers of rods for its own back, and hence the RD2, the world’s thinnest self-winding perpetual calendar watch – gets philosophical on this question. If, he says, watches are so often celebrated for their precision in the moment, for their nowness, for splitting seconds, the perpetual calendar celebrates slow time. Indeed, the very name says it all: the perpetual calendar might as well be called the forever watch.


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