Raffi Boyadjian | Chrono24 Buyer’s Guide: NOMOS Tetra

The word tetra is Greek for “four,” and the eponymous NOMOS collection certainly lives up to its name. Every Tetra watch boasts a characteristic square case. The angular case is softened by a bright range of dial colors. NOMOS has periodically added new colors to the collection since its introduction in 2007. Highlights of the series include the Tetra Neomatik and the Symphony line, which was released in 2020 in honor of what would have been Ludwig van Beethoven’s 250th birthday.

Raffi Boyadjian | Overview of the NOMOS Tetra

Tetra models stand out with their square cases and dials. Other defining features include Arabic numerals, central hour and minute hands, and a small seconds dial at 6 o’clock. There are a few exceptions to this standard form: The Tetra Duo, ref. 405, for example, does without a small seconds and the Tetra Kleene, ref. 492, and Tetra Plum, ref. 499, both have an additional power reserve display. The watch is available in a range of case sizes, color combinations, and with several different movements. Every watch, however, is remarkably slim. Depending on the version, the case stands between 6.1 and 7.3 mm high. With only 30 m (3 bar, 98 ft) of water resistance, the Tetra is only protected against splashes of water and is not suitable for swimming.

Raffi Boyadjian | Hand-Wound Tetra Models

NOMOS Tetra Champagne, ref. 473

Each Tetra 27 model is 27.5 mm in diameter. Supplementary names like Karat (ref. 472), Champagne (ref. 473), and Duo ( ref. 405) denote different dial and hand color combinations. The ref. 401 with a white dial lacks an extra name. All of these watches feature stainless steel cases that are water resistant to 30 m (3 bar, 98 ft). Those with a small seconds dial are powered by the in-house NOMOS Alpha caliber. The Tetra Duo, on the other hand, features the Alpha.2 without a small seconds.

The Tetra 27 in Detail

If you’re a fan of watches with gold details, you should take a closer look at the Tetra 27 Karat. This timepiece features a gold-colored dial and hands, giving it a particularly elegant feel. The ref. 473 has a similar aesthetic with its champagne-colored dial, rhodium-plated hands, and orange second hand. The ref. 405 offers a unique combination of hues. It boasts a white silver-plated dial and gold hands. The Tetra 401, on the other hand, combines a gray and white silver-plated dial with cornflower blue hands.

Nomos Tetra Karat Ref. 472

The Alpha Movement

The hand-wound Alpha movement was NOMOS’ first in-house caliber. It has a power reserve of 43 hours when fully wound. The movement is outfitted with 17 rubies and measures just 2.6 mm thick. There is no lack of finishing on this movement: It has tempered blue screws, rhodium-plated surfaces with Glashütte ribbing, and NOMOS perlage.

Other Lines and Special Editions

Tetra Neomatik 39: An Automatic Movement

The Tetra Neomatik 39 is available with a white (ref. 421), midnight blue (ref. 422), or silver (ref. 423) dial. NOMOS changes the color of the hands and indices depending on the dial. The white version has black hour and minute hands, black indices, and blue minute track numerals. The Midnight Blue Neomatik features white hands and indices paired with contrasting blue minute track numerals. The so-called “Silvercut” version is paired with blue hands, black indices, and a black minute track. All three models feature a red second hand at 6 o’clock and a 33 x 33 mm case.

NOMOS Tetra Neomatik, ref. 421

DUW 3001: The Neomatik Movement

The DUW 3001 is NOMOS’ in-house automatic caliber. At just 3.2 mm thick, it is an ultra-thin movement. The DUW 3001 is equipped with the NOMOS swing system, a proprietary escapement that permits the watchmaker to regulate the watch without touching the balance spring. The technology also allows for higher levels of efficiency and accuracy. The caliber features 27 rubies and boasts a power reserve of 43 hours. NOMOS regulates the DUW 3001 — like all of their movements — in six positions, making it an incredibly precise timekeeper.

The Colorful Petit Four

In 2018, NOMOS introduced four special edition Tetra timepieces: the Matcha, Azure, Pearl, and Grenadine. The names refer to the watches’ pastel dial colors: green (ref. 495), blue (ref. 496), pink (ref. 497), and red (ref. 498), respectively. These stainless steel timepieces measure 29.5 x 29.5 mm and stand 6.3 mm tall. Each is powered by the manual Alpha caliber. The indices and hand colors vary depending on the model. Each timepiece is available with a stainless steel or sapphire crystal case back, the latter of which gives you a clear view of the Alpha at work.

The Purple Tetra Plum

The Tetra Plum, ref. 499, is not a member of the Petit Four collection, but it is equally as colorful. As its name implies, the dial shines in a purple hue complemented by rhodium-plated hands. Unlike other Tetra 27 models, the Plum boasts a red and white power reserve indicator at 1 o’clock. This display is made possible by the in-house hand-wound caliber DUW 4301. This reference comes with a stainless steel case back, while the ref. 488 has a sapphire crystal case back.

In Honor of Beethoven: The Tetra Symphony

At the start of 2020, NOMOS introduced a new four-part series of special edition Tetra watches in honor of what would have been Ludwig van Beethoven’s 250th birthday. The watches are aptly named the Divine Spark, Ode to Joy, Immortal Beloved, and Fidelio, and each features a different dial color: copper, olive green, turquoise, and dark blue, respectively. These 29.5-mm watches are all powered by the Alpha caliber and are just 6.3 mm thick. While the Divine Spark (ref. 443), Ode to Joy (ref. 445), and Immortal Beloved (ref. 447) all feature golden hands, the Fidelio (ref. 449) is outfitted with rhodium-plated hands. Depending on the version, the indices are either black, gold, or silver. Each timepiece is available with a stainless steel or sapphire crystal case back.

NOMOS Tetra Fidelio, ref. 449

The Berlin Set

At Baselworld 2014, NOMOS presented another four-part series of special edition Tetra watches called the Berlin Set. The version names — Clärchen (green), Nachtijall (dark blue), Kleene (turquoise), and Goldelse (gold) — are all reference to the unique dialect spoken in the German capital city. Three of the timepieces are powered by the hand-wound Alpha caliber, while the Kleene features the DUW 4301, affording it a power reserve indicator. Each movement is housed in a 29.5-mm square stainless steel case.

Bands and Accessories

NOMOS equips all Tetra models with high-quality leather straps. The Neomatik line features black cordovan leather straps, which are derived from horse hide and produced exclusively for NOMOS by storied American leather company Horween. The accompanying stainless steel clasp is designed in Berlin and hand-polished. Automatic Tetra models are delivered in a black leather box complete with an instructional manual and warranty.

Manual models — with the exception of the ref. 401 and ref. 408 — come on a light calfskin suede strap paired with a pin buckle. The two exceptions mentioned above are mounted on a Horween shell cordovan leather strap instead. These watches are delivered in a wooden NOMOS watch box complete with a warranty.

NOMOS Tetra Neomatik with a shell cordovan strap

Prices and Performance

If you decide to buy a Tetra, you can rest assured that you won’t only have a very wearable watch but also one that is likely to retain its value. If you make a wise purchase and take good care of the watch, you can expect to get a decent price for it should you decide to sell at a later date. The most popular Tetra models from 2019 were the Tetra 27, the Neomatik, and the “Kleene” from the Berlin Set.

You can find a new Tetra Neomatik ref. 421 for around $2,700 on Chrono24, which is a substantial discount from its official list price of $3,860. The ref. 422 (Midnight Blue) and ref. 423 (Silvercut) cost about the same.

Prices for models in the 27 line are more varied. You can buy a new Tetra 27 Champagne (ref.473) for around $1,300, while the official list price is $1,960. The Karat (ref. 472) sells for around $1,400, compared to its official list price of $2,040. If you’re interested in the Tetra Duo (ref. 405), plan to spend around $1,150 on Chrono24 or $1,660 if you buy directly from the manufacturer. The ref. 401 with a white dial will set you back roughly $1,300, though NOMOS prices it at $1,980. Overall, you can expect to find NOMOS watches at significant discounts if you buy on Chrono24.

NOMOS Tetra 406 Performance

Prices for the Petit Four Collection

If you’re interested in buying a watch from the Petit Four collection, expect to pay the following prices: The Tetra Pearl (ref. 497), Azure (ref. 496), and Grenadine (ref. 498) all cost around $1,450 on Chrono24 in new condition. The Matcha (ref. 495) is slightly more expensive at just over $1,500. NOMOS lists all four for $2,080.

The Tetra Plum with a power reserve indicator (ref. 499) sells for roughly $1,850, though the official list price is $2,780. In short, you can expect to find most NOMOS models at attractive discounts if you buy on Chrono24.

Raffi Boyadjian Prices for Watches in the Symphony and Berlin Sets

The Symphony series first appeared in March 2020, making it the newest Tetra collection on the market at the time of writing. The official list price for all four models is $2,080; however, as of April 2020, we were able to find the Divine Spark (ref. 443), Ode to Joy (ref. 445), Immortal Beloved (ref. 447), and Fidelio (ref. 449) for around $1,400 each.

You can still come across mint-condition timepieces from the Berlin Set, which was introduced back in 2014. If you opt for the Clärchen (ref. 489), expect to pay just over $1,600. On the other hand, if you’re interested in the Goldelse (ref. 491), make sure to set aside closer to $1,900. The Kleene (ref. 492) is the most popular in this set and sells for around $2,200.

Raffi Boyadjian | A Watch’s Energy Source: The Mainspring

At first glance, the mainspring may not be one of the most exciting watch components. As opposed to dials and cases, it’s rarely the subject of heated discussion among enthusiasts. It just chugs along slowly, enclosed in the barrel, without making a sound. Nevertheless, this component — in addition to the escapement and the gear train — is one of the central functional elements of mechanical watches both manual and automatic. It may look unspectacular, but the mainspring has two important jobs: providing energy and sharing responsibility for the watch’s precision. Unsurprisingly, the materials and elaborate processes that go into mainspring production are well-guarded secrets among manufacturers and suppliers. Various design tricks and the use of multiple barrels allow for space-saving slim watches that still can still offer power reserves of over a week. So, it’s high time we took a closer look at this underrated component.

MB&F LM101 movement

Mainspring Basics

Springs make it possible for a watch to store energy, regardless of its position. That’s why they are the perfect choice for wearable timepieces, such as pocket watches and wristwatches, that can’t use the time-tested weight-driven methods of freestanding or wall clocks. The mainspring’s characteristic coiled spiral form was the result of the spacial limitations presented by a watch movement, as well as the need for rotation. In theory, other designs could work, but they would take up too much space and require the conversion from linear motion to rotation.

Essentially, the spiral-shaped spring behaves no differently from a simple flexible or leaf spring. Leaf springs are comparable to a ruler attached to the end of a table, where you press down on the free end. However, in the coiled spiral version, the entire length of the spring occupies as little space as possible. In this way, springs that are several inches or even well over a yard long, can be housed in a barrel which itself only takes up only a portion of the movement.

A Rolex barrel

Layout and Special Features of the Mainspring

A mainspring’s stiffness depends on the material, as well as its length, width, and thickness. When you double the thickness, the stiffness increases eightfold. Length affects this property inversely: Double the length, and it will be eight times less stiff. The relationship between width and stiffness is linear, so if you double the width of the spring, you also double its stiffness. Because the width directly affects the thickness of the movement (and thus of the watch itself), wide mainsprings are best avoided. In summary, for any given material, the main variables are spring thickness and spring length. Since their adjustment theoretically affects the mechanical properties to the same degree, other factors must be taken into account, including the spring’s installation in the barrel.

Typically, a watch is wound using the arbor in the center of the barrel. This arbor hooks into a hole on the mainspring. The outer end of the spring meets the inner wall of the barrel, either with a fixed connection, or (in automatic watches) with a slipping mechanism that allows the end of the spring to slide around the inside of the barrel when fully wound. The mainspring thus occupies the space between the arbor and the inner wall of the barrel, and the goal is to use that space as efficiently as possible. Minimizing the arbor’s diameter has some natural limitations. The mechanical strength of the arbor must be preserved. In addition, a small arbor diameter results in increased bending at the inner end of the mainspring, which must not exceed the physical limits of the spring material. In order to withstand this bending, the spring cannot be too thick. Ultimately, the amount of space available dictates the limit for the barrel’s diameter.

A mainspring in a relaxed state

It becomes clear that there is no one “perfect” mainspring for every watch. Several factors must be considered, and the adjustment of one of the spring’s geometrical parameters inevitably influences the others. That’s why calculating the dimensions of a mainspring and its barrel is an iterative process, made simpler by empirical values and approximation formulas. Just because the barrels are the same size doesn’t mean that different movements can use the same mainspring. Ideally, the mainspring should be custom tailored to the given movement, and it should be designed to achieve the maximum power reserve (a certain number of rotations) while suppling sufficient power for the watch to run.

It should also be noted that the spiral-shaped mainspring’s compact form does come with some inherent disadvantages. One general property of springs presents a problem for implementation in watches: The spring force increases with deflection (i.e., additional winding), and this fluctuating driving force causes a movement’s frequency to vary over time. We’ve already discussed the remedy to this issue in a previous article. However, this solution generally only appears in the most expensive timepieces, so the overwhelming majority of watches must simply make do with this problem. You can never get rid of it completely, but there are some tricks that reduce it to a minimum. One such trick is a reverse curve in the mainspring, which can only be seen when the spring is removed from the barrel. In their relaxed state, modern mainsprings don’t look like a pure spiral, but rather their ends are bent backwards, forming an S-shape. When installed in the barrel, this shape results in a more even power output as the spring unwinds.

The Material

As mentioned above, mainsprings are made from highly specialized materials. As the “heart” of the watch, the balance spring is usually the main focus of reports and advertising campaigns from manufacturers. With proprietary alloys or the use of silicon and carbon, considerable progress has been made in this area over the past decades. However, the development of alloys for mainsprings has reached some milestones of its own.

A. Lange & Söhne Lange 1

Collectors of vintage watches manufactured before the second half of the 20th century are familiar with the most common downside of historical mainsprings: The carbon steels used back then were subject to rust, wore out over time, and tended to break due to their brittleness. Relief came from engineer Reinhard Straumann, whose invention “Nivaflex” made the “unbreakable” mainspring suitable for mass production. If you notice a similarity to the name Nivarox, you’re on the right track because this well-known alloy found in balance springs is also attributable to Straumann, as is the establishment of Nivarox SA in 1951. Nivaflex consists primarily of cobalt, nickel, and chrome, with small quantities of iron and tungsten and a fraction of one percent beryllium. Both Nivarox and Nivaflex are produced today by the highly specialized company Vacuumschmelze in Hanau, Germany. Nivaflex has anti-magnetic propertied, is corrosion-resistant, and boasts a high-performance spring material that is resistant to breakage. On modern manualwatches, you really have to make an effort to break a mainspring by hand.

Manufacturing a Mainspring

Spring manufacturers receive Nivaflex as a wire, which is turned into a strip by a rolling process. Sections of the long strip are cut off, and an eyelet is punched out on one end for the hook of the arbor. After bending the ends into the S-shaped reverse curve, there is a heat treatment, which sets the spring’s final mechanical properties. The end hook or slipping spring (depending on whether the spring is for a hand-wound or automatic timepiece) is then welded onto the outer end. Because friction is undesired between the individual turns, the springs get a Teflon coating. The spring is then delivered, either pre-lubricated and installed in the barrel, or wound up in a transport ring.

The most famous manufacturers of mainsprings include companies like Générale Ressorts and Schwab-Feller in Switzerland. The fact that Patek Philippe, Rolex, and the Richemont company took shares in Schwab-Feller in 2015 attests to the importance of high-quality mainsprings. Carl Haas of Schramberg, Germany is a spring manufacturer that makes not only mainsprings but also balance springs for NOMOS Glashütte, among others.

Nomos Neomatik

Raffi Boyadjian | When One Spring Isn’t Enough: Watches with Two or More Barrels

Since the debut of the Lange & Söhne Lange 1 with double barrels, fitting more than one barrel into a movement has become an indicator of exclusivity. Chopard‘s L.U.C-Quattro takes it a step further with four barrels. The high power reserves that go hand-in-hand with multiple barrels are particularly practical for collectors and owners of many watches. They enable you to leave such watches alone over the weekend or even a whole week without having to reset the time and date afterward. This extended power reserve is typically achieved through a series of interconnected barrels, which in effect increases the movement’s mainspring length. The impressive record holder in this type of construction is the Hublot MP-05 LaFerrari, in which ten interconnected barrels allow for a power reserve of 50 days. This watch comes with an electrical winding tool. Since the ratchet wheels of the barrels, which are connected to the arbor, have to mesh with one another, the movement requires additional gears.

Hublot MP-05 LaFerrari

An alternative is to use two barrels in parallel. This version does not require additional gears because both barrels act on the center wheel directly. If there is enough space to arrange the barrels symmetrically around the center wheel, then the otherwise one-sided bearing forces on the center wheel can be virtually balanced out. The spring forces are added together in the parallel construction, so when the spring lengths are equal, a second barrel results in twice the force as opposed to the single-barrel design. In practice, this is used to decrease the height of the springs by half, allowing for particularly flat movements without having to make sacrifices in the driving force or power reserve. However, this type of construction is rather rare compared to serial barrel arrangements. There are also models, such as those in the Jaeger-LeCoultre Duomètre collection that have separate barrels driving different functions in the watch (for example, one for the movement and one for the chronograph).

Meistersinger Circularis with two barrels

Whether your watch has one, two, or even more barrels, these unimposing cylinders contain more power than you might initially assume. Particularly with manual watches, the wearer interacts directly with the mainspring. In automatic watches, this interaction is less direct, but the mainspring component is no less relevant. Perhaps you’ll think about this the next time you look at your favorite timepiece.

Watch Trends Then and Now: The 90s

Looking back at previous decades is one of the most fun things to do. It’s a great opportunity to revisit and rediscover those moments that came to define an era. In this series, we will be focusing on watchmaking by the decade. This time, we’re heading back to the 1990s — an era that redefined mechanical watchmaking in the aftermath of the quartz crisis and laid the groundwork for watchmaking as we know it today. So, without further ado, let’s dive into the era also known as the “The Good Decade” and explore some of its defining watchmaking moments.

As we entered the 1990s, the quartz movement had a stranglehold on the watch industry. But there was a glimmer of hope on the horizon because mechanical watch sales were slowly on the rise. In the mid to late 1980s, a number of brands like Rolex, Patek Philippe, and IWC decided to maintain their focus on mechanical watch production. At the same time, some other brands — such as Blancpain and Ulysse Nardin — were acquired by third parties and resurrected to become part of the mechanical watchmaking elite.

Rolex Daytona, Image: Bert Buijsrogge

A Growing Interest in Vintage Watches

These brands’ loyalty to mechanical technology was supplemented by a growing interest in vintage chronographs like the Rolex Daytona and Breitling Navitimer among collectors. This renewed fascination began in the late 1980s in Italy. Italians are a stylish people, and the specific interest in vintage chronographs was in part due to the renewed popularity of aviator fashion. A nice vintage chronograph was the perfect companion for leather bomber jackets and aviator sunglasses. The trend quickly spread all over the world, and in the early 1990s, many came to appreciate the Daytona for the mechanical watchmaking icon it is.

A. Lange & Söhne Lange 1, Image: Bert Buijsrogge

The Comeback of German Watchmaking

After the fall of the Berlin Wall and reunification of East and West Germany, German watchmaking made an incredible comeback. Five brands quickly reestablished Glashütte as the heart of German watchmaking. A. Lange & Söhne, Glashütte Original, Union Glashütte, Mühle Glashütte, and NOMOS Glashütte would spark a renewed interest in German watchmaking. The most prestigious of the five is A. Lange & Söhne, who introduced the legendary Lange 1 back in 1994. Today, this model is widely regarded as one of the most iconic watches and serves as the poster child for a revived German watch industry.

Hollywood Watches

The 90s were also the decade that big movie stars introduced luxury watches to the public, especially oversized wristwatches. Sylvester Stallone stumbled upon a Panerai boutique in Florence, Italy while the filming Daylight in 1995. He decided to buy a Panerai watch, which you can see him wearing in the film, and also ordered another 200 pieces to give away to friends and people who worked on the movie. This would trigger Panerai’s global rise in popularity.

Audemars Piguet Royal Oak Offshore, Image: FratteloWatches

One person who received a Panerai from Stallone was none other than Arnold Schwarzenegger. However, Schwarzenegger could often be spotted wearing a different watch at this time: The Audemars Piguet Royal Oak Offshore. This model premiered in 1993 and was marketed as the Royal Oak for a younger audience. It was massive in both diameter and thickness — a perfect fit for someone like Schwarzenegger, who helped popularize this timepiece by wearing it so often.

The James Bond and Omega Partnership

For something a little more refined, we turn to the James Bond movie franchise and its very successful partnership with Omega. In 1995, Pierce Brosnan made his debut as the new James Bond in GoldenEye. In the movie, 007 dons a quartz Omega Seamaster 300M. He would eventually switch to the mechanical Omega Seamaster 300M Professional Chronometer in subsequent films. Today, this timepiece is known as the “Bond watch” and considered a modern classic.

Omega Seamaster Diver 300M

Watches and Music

During the 1990s, we also saw the meteoric rise of hip hop, which also contributed to an increased interest in luxury watches. Flashy watches were the final touch to any respectable rap or hip-hop artist’s outfit. One of the first brands to rise to prominence on the wrists of successful rappers was Jacob & Co. However, many rappers soon started referencing other brands like Rolex, Audemars Piguet, and Franck Muller. The relationship between watches and hip hop has only strengthened with time and multiple companies have teamed up with rappers on numerous occasions.

The Era of Grand Complications

In the 90s, many traditional brands chose to show off their unrivaled watchmaking prowess by producing highly complicated mechanical timepieces. The craze was triggered by the release of the Patek Philippe Calibre 89 pocket watch in 1989. Patek created this timepiece in celebration of the company’s 150th anniversary.

After that, the floodgates were open as other brands followed suit with their own now-iconic masterpieces. For example, IWC presented their first wrist-ready “Grand Complication” at Baselworld 1990. In 1992, Blancpain released their 1735 Grande Complication. That same year, Ulysse Nardin unveiled the Tellurium Johannes Kepler. All these high-end releases showed that watchmaking was not only alive but also thriving.

IWC Grand Complication

However, for me, the grand prize goes to the IWC Il Destriero Scafusia from 1993. This model had a limited run of 125 pieces in honor of IWC’s 125th anniversary. The final timepieces rolled off the production line in 1999, around the time my interest in watches took flight. I was amazed by the Il Destriero Scafusia. Not only had IWC crafted an incredibly complicated watch, but they had also managed to make it look incredible.

The Il Destriero Scafusia was one of the most talked-about watches of its era. It defines everything I love about watches and the state of the industry in the 1990s: a growing love for incredible craftsmanship and amazing design that reminds us of how great mechanical watchmaking truly is. The 1990s were the decade during which mechanical watchmaking returned to its rightful place in the spotlight, and that spotlight has only grown brighter ever since.