DSTB 42 Platinum

DSTB 42 Platinum & DSTB 42 Red Gold

Beating out a new rhythm 

Arnold & Son reinterprets one of its most personal collections. DSTB 42, which stands for ‘Dial-Side True Beat’, reveals its true-beat seconds mechanism on the dial side. Under its openwork and finely chamfered gold bridges, its characteristic anchor powers a seconds hand at a broad rhythm. The case and movement of this essential timepiece have been entirely revised, refined and improved. With two inaugural limited series – one in red gold, the other in platinum – Arnold & Son reaffirms its historic attachment to marine chronometers.

The true-beat seconds function is characteristic of the instruments that John Arnold supplied to the Royal Navy. Their escapement used to beat at one oscillation per second, naturally indicated by a sweep-seconds hand. This explicit function inspired Arnold & Son to create one of its most iconic complications: ‘True Beat’, also known as deadbeat seconds. The distinctive feature of the DSTB collection is that it displays this mechanism in full on the dial, hence the ‘Dial-Side True Beat’ name, delivering watchmaking, design and spectacle all in one.

Great leap

Watchmaking, because all true-beat seconds require a dedicated mechanism. No escapement in a compact watch, especially one worn on the wrist, functions at a native frequency of one oscillation per second. Here, the sweep-seconds hand on the DSTB 42 jumps from second to second, powered by a mechanism similar to an escapement, developed by Arnold & Son’s watchmakers.

Great bridges

Design, because this true-beat seconds needed to be displayed in a way that reflects its historic importance for Arnold & Son. The choice to place it on the dial side creates an additional level in the calibre. This, in turn, required three dedicated bridges, fashioned in line with the Arnold & Son aesthetic, whose graphic design and finishes give the dial its truly unique appearance. They are openworked, three-dimensional and carefully crafted from red or white gold, depending on the DSTB 42 version. This true-beat seconds mechanism fills the space with its presence, balanced out by the off-centred hours dial in white opal. 

Great anchor

Spectacle, because the even, slow and aesthetic functioning of the true-beat seconds mechanism catches the eye. It symbolises both Arnold & Son’s watchmaking expertise and its roots, down to the anchor-shaped counterpoise reminiscent of marine chronometers. It goes up and down as the underlying calibre does its work, controlling the large seconds hand.

New size

The DSTB collection was one of the founding pieces in the Arnold & Son catalogue. Its first version measured 44 mm in diameter. It featured a calibre that was 7.40 mm thick, allowing a 45-hour power reserve. The DSTB 42 improves on each of these points. The exclusive Manufacture calibre A&S6203 is 5.54 mm thick and offers 55 hours of autonomy. The case drops to 42 mm in diameter and settles for a total thickness of 12.95 mm.

New details

The DSTB 42 Red Gold comes in a 5N gold case, whose copper content gives it the name red gold. This warm colour is paired with a blue PVD-treated dial for a soothing overall effect. The DSTB 42 Platinum offers the opposite contrast, with its combination of 950 platinum and a dial featuring a rose-gold PVD treatment known as ‘salmon’. In both versions, the dial is sunray-brushed before being tinted, the starting point of the finish coinciding with the centre of the true-beat seconds.

New calibre

The DSTB 42 Red Gold and the DSTB 42 Platinum are powered by the calibre A&S6203, which has been entirely developed, machined, assembled and adjusted in the Arnold & Son Manufacture. Designed to work in harmony with the true-beat seconds mechanism, this calibre is self-winding thanks to an oscillating weight in 22-carat gold. It features a 55-hour power reserve and a regulating organ oscillating at 28,800 vibrations per hour.

Technical specifications

• Hours, minutes, true-beat seconds

Movement

• Calibre: A&S6203, self-winding mechanical
  
• Jewels: 32
  
• Diameter: 33 mm
  
• Thickness: 5.54 mm (8.33 mm on the bridges of the true-beat seconds)
  
• Power reserve: 55 hours
  
• Frequency: 4 Hz / 28,800 vph
  
• Finishes: 
  mainplate: palladium finish, côtes de Genève stripes radiating from the centre
  bridges: polished and chamfered
  wheels: circular satin-finished
  screws: blued and chamfered, polished heads
  oscillating weight: 22-carat gold
  true-beat seconds mechanism: 18-carat gold bridges, polished and chamfered 

Dial                               

• Sunray-brushed, with salmon PVD treatment

Hours dial                     

• White opal

Case

• Material:  Platinum (Pt 950)
  
• Diameter: 42 mm
  
• Thickness: 12.95 mm
  
• Crystal: Domed sapphire with an anti-reflective coating on both sides
  
• Case back: Sapphire with an anti-reflective coating
  
• Water resistance: 3 bar (30 metres/100 feet) 

Strap

• Material: blue alligator leather, hand-stitched
  
• Clasp: pin buckle, platinum (Pt 950)

References                   

• 1ATCX.P01A.C200X

Limited editions            

• 38 timepieces
  

Astronomy, Chronometry and World Time

Arnold & Son's three founding principles

Throughout human history, measuring time has always referred to the stars. It was by observing certain stars and understanding their cycle that the first calendars were established with impressive accuracy. It took several millennia before this precision was enclosed in a timepiece like the ones designed by John Arnold. 

The golden age of maritime explorations and discoveries ushered this precision into a new technical ideal – determining longitude at sea. Its immediate corollary was the identification of local time, which changed constantly as the observer moved along an east-west axis. Astronomy, chronometry and what we now call world time are thus inextricably linked within one and the same question, to which John Arnold and his son devoted their lives, their art and their genius. 

This is how these three dimensions – astronomy, chronometry and world time – have come to be embodied in the House's contemporary timepieces.  Echoes of John Arnold's inventions and preoccupations, these pillars represent the foundations on which the Arnold & Son collections are based.

Chronometry: Be accurate

Rate accuracy, which is known as chronometry, is the key requirement of Arnold & Son's contemporary watchmaking. It is the standard of excellence for its collections, the first condition to be met and constantly checked, whether it is at the forefront or in the background of a watch designed by Arnold & Son. It is the most discreet of a movement's characteristics. 

When building an Arnold & Son collection, all the thinking is focused on this chronometry. The manufacture calibres are based on advanced technical fundamentals that are not necessarily the best known. One of them is the choice of small, lightweight balances capable of rapidly returning to their isochronous rate after the latter has been disturbed by inevitable everyday shocks. Another is the routine use of large barrels or even two series-coupled barrels to store the energy required for the movement to function.  They consequently provide Arnold & Son's manual winding calibres with above-average power reserves of 90 hours and more. A third is the particular attention paid to manufacturing the gear trains, roller-burnishing the pinions and polishing the gear teeth, as well as the precision of the machining and therefore the relative positions of the moving parts, a key concept in rate accuracy.

The tourbillon (or the fact of putting the regulating organ in rotation on its axis to best adjust the effects of gravity on the balance and its hairspring) was patented after John Arnold's death, but it was undoubtedly at the heart of his chronometric research and discussions with his friend Abraham-Louis Breguet, who incidentally assembled his first tourbillon on a John Arnold pocket watch in homage to this great watchmaker. Nowadays, the tourbillon has become a must in Arnold & Son collections.

While the tourbillon was not a complication in John Arnold's time, constant force underpinned the design of his marine chronometers. The regularity of the rate of the sprung balance relies on the consistency of the energy that it receives. However, this naturally fluctuates due to the circular and spiral nature of the mainspring contained in the barrel. To achieve a perfectly smooth torque, in other words a constant force, Arnold & Son uses a one-second constant-force mechanism. Housed just before the escapement, it stores up a small but always equal amount of energy in a secondary spring, the remontoire. Thus, every second, the sprung balance receives very precisely the same force to power its oscillations. These become more even, thereby creating the conditions for a high-precision rate.

Arnold & Son also works with another of John Arnold's historical chronometry indicators: deadbeat seconds, a mechanism that was indispensable to navigators at the time for calculating longitude. This mechanism advances one step each second, rather than six or eight smaller jumps in sync with the frequency of the balance. Instead of the term deadbeat seconds, Arnold & Son prefers a name whose very sound means accuracy: “true beat second”. Its jump is a signature of John Arnold's marine chronometers and a complication that is still alive and well in the House's collections.

Astronomy: Under the sky

The Pole Star, Southern Cross, astrolabes and sextant: measuring time has relied on the recurrence of astronomical phenomena in order to find long, reliable points of reference there that can be used under any conditions. The fruit of the human ingenuity, patience and dedication of countless observers and astronomers from every culture, these markers of cyclical time are foundational for Arnold & Son watchmaking.

Astronomical complications are a signature of Arnold & Son collections, with the moon as the heavenly body of choice, main subject and major inspiration. The distinctive feature of the Brand's moon phase timepieces is that they feature “astronomical” display precision as a matter of course. This term corresponds to an accumulated one-day deviation in the moon phase display every 122 years. Since setting this complication requires great finesse, the Arnold & Son moons generally have a double display with a secondary indicator on the case back next to the movement. This extremely rare display bears witness to Arnold & Son's involvement in all types of development and reflects its favoured themes, which are as much chronometric as astronomical.

Over and above their precision, Arnold & Son's moon phases attract all the light, either with a large moon opening up over half the dial, or with a 12-mm three-dimensional rotating moon, making it the largest of all moons. Whether in two or three dimensions, the moon is always treated as a small work of artistic craftsmanship, composed of materials that are rare in watchmaking such as marble or Paraíba tourmaline, or delicate such as mother-of-pearl, meteorite or aventurine glass. The Arnold & Son moon also shines at night, often with a subtle addition of luminescent material. 

World Time: Here, elsewhere, everywhere

With ocean navigation, humankind divided up the world and invented longitudes, which were calculated by comparing the local time, observed using the sun, and the time at a starting point, kept by an extremely reliable timepiece. John Arnold was one of the leading suppliers of chronometers to the British Navy. He was the one who successfully improved the reliability and simplified the production of these indispensable marine chronometers, so much so that he became a benchmark among great explorers such as James Cook and later Dr David Livingstone. The indication of several time zones is therefore integral to Arnold & Son's watchmaking identity.

As this navigation was itself inseparable from cartography, for this world time complication Arnold & Son has chosen to depict a three-dimensional terrestrial hemisphere, making it possible to tell what time it is at any point.

In parallel to this graphic vision, Arnold & Son has developed a second approach to the time elsewhere in the world: with a double tourbillon featuring two distinct rotating regulating organs, making it possible to follow time zones offset by 15, 30 or 45 minutes compared to a full hour – a freedom in terms of setting that remains extremely rare. 

Once again, and because this double display is based on a profoundly chronometric complication, Arnold & Son’s fundamental principles are interwoven. One never advances alone; there are always two – if not three – together. This is how a pillar's strength is measured: it relies on the next one, creating the conditions for a solidity that stands the test of time.