cazalea
[Seiko Moderator]
17046
I believe it’s the best so far!
At the birthplace of Spring Drive, the Shinshu Watch Studio, craftsmen and women assemble timepieces by hand, from the case, dial, hands and indexes to all other components. At every step of the process, from development and design to manufacture, assembly, and adjustment, talented and expert craftsmen and women aim for the highest standards.
Caliber 9RA2 is the Spring Drive movement that best embodies these skills and their passion.
Caliber 9RA2 has an accuracy rate of ±10 seconds per month and utilizes the Offset Magic Lever on the automatic winding system to reduce the movement’s thickness by 0.8mm. By moving the position of the crown further back, the watch’s center of gravity is lowered and a perfect fit on the wrist results.
The Dual-size Barrels are of differing sizes and arranged to allow for expanded capacity while conserving space. This achieves a 120 hour power reserve. The One-piece Center Bridge guarantees the movement’s strength, durability and shock resistance. Together, these innovative technologies define the next-generation Spring Drive movement, Caliber 9RA2
Caliber 9RA2 achieves a high accuracy of ± 10 seconds per month in large part by using a high precision Spring Drive package IC, which is a vacuum-sealed package consisting of a carefully selected crystal oscillator aged for three months and an IC that is powered by an extremely small electric current.
The oscillation of a crystal oscillator is susceptible to temperature fluctuations, so Caliber 9RA2 utilizes a temperature sensor located within its special silicon-on-insulator IC (SOI-IC) to collect temperature data 540 times daily, determine the influence of temperature changes within the IC and compensate for variations in the oscillator’s performance.
Placing the crystal oscillator and the IC within a single, vacuum-sealed package eliminates temperature differences between the IC and the crystal oscillator, allowing for highly precise temperature adjustments. Installing all wiring connecting the crystal oscillator with the IC within the vacuum-sealed package also prevents changes in humidity from influencing the movement in addition to the shielding the movement from the influence of static electricity and light.
www.grand-seiko.com
Grand Seiko Evolution 9
In 2021, Grand Seiko introduced a high-beat watch inspired by the slender and beautiful white birch trees of the Hiraniwa Plateau in northern Japan. This timepiece was warmly praised by watch fans worldwide for its intricately textured dial and for the re...
Argh
Thanks - I assume this is the press release? GS does a lot of things nicely. I’m not going to go over them. May I please instead politely recount a few of my frustrations with GS? First, the extraneous dial text. It’s like they’re channeling Rolex…but not...
Yes, the copy is from compiled from several press releases and the website.
You're entitled to express your opinion. As for ritual flogging, that depends. Not everyone is entitled to that! As regards the numbering scheme, I have partially deciphered it, and you can see the results for yourself: A B C D E F G H I J K L M N O P Q 1...
Great work Mike …
Your spreadsheet detailing the references is a labour of love and I’m sure it will be greatly appreciated. Thank you for all the effort.
Yes…
As it is highlighted as a link I did and was pleasantly surprised. Thank you again as I’m enjoying exploring it.
A watch that nobody asked for?
I thought the "white birch" was one of the special dials which helped showcase the fantastic Caliber 9SA5. I do like spring drive in general and find the new iteration interesting. But why put the new movement in a replica of the automatic? This makes so ...
A range of improvements …
On a watch that’s becoming a classic for GS… Isn’t that called evolutionary progress.
I think perhaps the Evolution 9 is a new generation of cases into which many existing/new movements will go
A GS watch "family" might be populated by manual wind, regular automatic, hi-beat, Spring Drive and/or quartz movements. NOTE: Chronographs are seldom sold by Grand Seiko and have their own sort of lineage and by necessity their own cases. This is not nec...
Thank you for this great post and overview (also for your excel with links!!)
I'm just starting to delve deeper into Seiko and have been considering the SLGA009: or even the (much more expensive) SLGA008 model: But also the model SLGH005 (Hi-Beat version) which - as we see - looks completely like the SLGA009 (these names…..) It's s...
Spring Drive
In theory, the Spring Drive might need service eventually. There is less stress on the watches as there is no start/stop, tic/toc of the movement. The smooth running, no-contact escapement/time regulation circuits have no wearing parts, other than pivots ...
Thanks a lot, cazalea!
This was very helpful. You mentioned that there are multiple levels of Spring Drive quality. Do you know if the SLGA009 and the SLGA008 have implemented the same quality of Spring Drive movement? Many thanks in advance Thomas
I believe it’s the best so far!
Caliber 9RA2 At the birthplace of Spring Drive, the Shinshu Watch Studio, craftsmen and women assemble timepieces by hand, from the case, dial, hands and indexes to all other components. At every step of the process, from development and design to manufac...
