Complications
patrick_y initiates a crucial discussion for Bulgari collectors, leveraging Google AI to compare the BVL 138 720 and BVL 138 721 calibers. His original post highlights the subtle yet significant differences between these movements, setting the stage for a deeper dive into their design philosophies and practical implications for wearers. This article synthesizes community insights to provide a comprehensive understanding of these two distinct Bulgari calibers.
| Feature | BVL 138 720 (Version 1, original) | BVL 138 721 (Version 2, updated) |
|---|---|---|
| Aesthetics | More elaborate and decorative. | Simplified and more modern, with a monochromatic look. |
| Finishing | Features more hand-finished interior angles (seven visible), anglage detailing, and gold lettering on the bridges. | Reduced number of interior angles (two visible) and uses rhodium lettering for text, simplifying the finishing process. |
| Winding system | Uses a less efficient automatic winding system with a smaller platinum micro-rotor. | Features a redesigned, more robust, and 40% more efficient winding system. It incorporates technology from other ultra-thin BVL movements. |
| Balance wheel | Smaller, 8mm four-arm balance wheel with gold plating. | Larger, 8.7mm two-arm balance wheel with a ruthenium look. The greater inertia improves accuracy and shock resistance. |
| Plates | Uses four larger plates and one smaller plate, which contributed to the decorative interior angles. | Uses only three plates, which simplifies construction, adds rigidity, and improves accuracy. |
| Barrel | The original barrel was an open-style component. | Uses a more stable closed barrel, which improves energy distribution and torque. |
| Jewel count | 36 jewels. | 31 jewels, with many of the "spacer jewels" from the 720 removed due to the redesigned plate structure. |
...it seems like they used to be much larger. Is a larger size no longer necessary because of modern materials?
I guess EVERYBODY would pick the first, right ?? To e all these changes done by the manufacture have only 1 goal and that is ' make is cheaper to produce so OUR profit margin get's bigger'
I have the original movement and never had any complaints about the accuracy and winding efficiency. And I certainly value the movement for its beautie....which was one of the main reasons for me to buy the watch! Best, Gerard
âĶI posted the following a while back: UPDATE: Thanks to a very helpful Bvlgari BVL 138 manufacturing video from WatchAdvisor, the latest iteration (gen. 2) of the calibre seems to be an upgrade, at least in terms of performance and reliability, because aesthetically speaking I personally think that gen. 1 looks better. Here are the details: 1. REDISIGNED AUTOMATIC SYSTEM: winding efficiency improved by approximately 40% The new system is incorporating the developments from another record-breakin
Mine is unfortunately not winding consistently. As you may remember, my watch often will stop at 2AM or 3AM despite having worn the watch for 20,000 steps each of the 2-3 days prior. So, when I wear mine for a week straight, I often have some small problems. I almost treat mine like a manual wind watch!
It's actually not that small. At around 8mm, for a modern movement, it's actually quite large. The only reason why you think it's small, is because it looks small, relative to the very large movement. The movement is really quite thin, at 2mm, but the movement diameter is extremely large at 36.6mm!!! That's a huge diameter movement! Which is difficult to fit inside a 40mm case! The movement does use a 21,600 VPH frequency. Pretty normal by today's standards. And an 8 mm balance wheel is also ver
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