Watchmaker’s Bench: Are All Chronographs Created Equal? Integrated Versus Modular Chronographs

Watches can be, well, complicated, and not all of the information out there is always accurate or reliable. So we’ve brought onboard Ashton Tracy, a seasoned watchmaker, to kick off a new series we’re calling Watchmaker’s Bench to explore some common questions, misconceptions, and ideas about watches. Today, we’re looking at integrated versus modular chronographs, but if there is something else you want Ashton to delve into, then send us your inquiry to [email protected] and we will consider it for the next installment.

As a watchmaker, I’ve seen it all—the good, the bad, and the ugly—when it comes to chronographs. One of the questions I often see asked is, are all chronographs created equal, and more specifically, what is the difference between an integrated chronograph and a modular one? That’ll be the primary focus of today’s article.

Over the last couple of decades, there have been two main types of chronographs: the integrated chronograph and the modular chronograph. An integrated chronograph is basically what it sounds like—the chronograph complication is built into the base movement and the two are designed to work together.

A modular chronograph is an entirely different beast. The chronograph complication on this type of movement is an independent unit that is attached to a previously existing base caliber. For example, a module can be attached to an ETA 2892, transforming it into a chronograph. It’s quite a clever idea, and I’m not the only one who thinks so. Modular systems have been used by Omega, Breitling, Audemars Piguet and even Richard Mille, just to name a few. But is one better than the other? Let’s examine more closely.

Integrated

Integrated chronographs come in many shapes and sizes. Some of the most popular integrated calibers are the Omega 321, Venus 178 (used in early Breitling Navitimers) and the Valjoux 72. Current examples of integrated chronographs include the Valjoux 7750, Rolex 4130, and the Zenith El Primero. All these movements are true pillars of the industry, and most would agree that they are among the finest chronographs ever produced.

Let’s take a look at the Valjoux 7750, one of the most ubiquitous chronograph calibers currently on the market. When I put one of these together, I first assemble the base movement (hours, minutes, and seconds). I usually check timing at this point to make sure there are no issues there. When that’s all cleared, I then turn to putting the chronograph components into place, which are connected to the base movement via the pinion running from the fourth wheel of the movement. This rocks back and forth to engage the chronograph seconds wheel when actuated. Finally, I add the automatic winding components and the oscillating weight.

Modular

There are two main chronograph modules on the market today. There is the module from Dubois Depraz, which can be mounted on any automatic base movement. Then there is the ETA 2894-2, which is essentially a 2892 paired with a module. The Dubois Depraz module has been mostly used with ETA calibers by Omega and Breitling, but it’s also seen limited action inside the Audemars Piguet Royal Oak and even some Richard Mille models.

The modular approach is not too dissimilar from the integrated one, but it takes a more indirect route to get there. Here, the base movement is fully assembled first, and then the module is connected to the dial side. A pinion is attached to the seconds wheel (the wheel that is normally paired to the seconds hand) of the base movement, and as a result the whole movement is controlled through that (as opposed to the chronograph being engaged via the fourth wheel, which is, as I noted above, how an integrated chronograph works).

So what is the actual functional difference?

I have serviced both varieties countless times, and both have their pros and cons. While both types of chronographs engage via one wheel, either the fourth wheel or the seconds wheel, they are in fact very different.

The “regular” timekeeping hands of an integrated chronograph are independent of the chronograph gearing—in other words, the hands are attached to the wheels directly driven from the base movement. The chronograph wheels and counters then engage via the fourth wheel. The fourth wheel has an extended pivot, which has another wheel mounted concentrically, and this wheel engages with the chronograph seconds wheel via another intermediate wheel that rocks back and forth to toggle the chronograph on and off. The chronograph seconds wheel has a finger mounted to the underside that engages the minute counting wheel every 60 seconds, thus pushing the minute counting hand one minute forward.

The module, on the other hand, is entirely dependent on itself. The entire watch (both the regular timekeeping and the chronograph timing function) runs through the seconds wheel pinion that has been attached via extra wheels in the module.

Integrated chronographs are very stable in the way they tell time due to the fact they aren’t technically connected; modules, on the other hand, aren’t as stable. When a modular chronograph is started and stopped, the regular seconds hand will shudder (almost as if it is receiving a knock) but this is simply a symptom of the gearing being run through the module and having all the hands run through that central pinion I discussed earlier. Also worth noting is that the minute recorder doesn’t have a jumper spring, so the minute hand runs continuously. This isn’t necessarily a bad thing, but it’s just not my preference. I prefer the crisp, clean jump of a minute counter.

Also worth noting is that the quality of a chronograph module isn’t always what it should be. They often aren’t finished as well as other movements are and they sometimes lack the tolerances one might expect from a modern movement. This is fine at a reasonable price point, but when shelling out for haute horologerie one expects a little more.

Then there’s the separate question of servicing. Most watchmakers will happily service an integrated chronograph, and for a modern caliber most can do so with considerable ease. Parts are generally readily available, and timekeeping and function are rarely a problem. Modules are a different story. The ETA 2894-2, for example, is very tricky to service. It requires expensive movement holders to re-assemble all parts correctly, and without these movement holders it is practically impossible to do. You do have the option of purchasing a new module, but this isn’t a cost effective practice. The Dubois Depraz is much more service-friendly (though not all too simple either), and I have repaired many over the years. However, I know many watchmakers that won’t touch them. The module can be fiddly to assemble due to the fact that all the wheels and levers sit mostly under one bridge.So to answer the question, “are all chronographs created equal?” I’d say no. Integrated chronographs will always outshine modular ones. However, when considering the answer to this question we must look at all the facts. Modular chronographs are successfully used by companies that produce base movements of a high standard, and if priced correctly, this is a positive for the market and for consumers.