The Soprod “Alternance 10” (also called the A-10, A10, and A10-2) is a Swiss Made movement based on the Seiko 4L25 design but produced in Switzerland under license. It is an advanced, slim automatic movement with modern technology and is not a clone of the ETA 2892A2 with which it competes.
The A10 is instantly recognizable thanks to its counter-clockwise balance cock and automatic winding rotor mounted with three screws and seven ball bearings. The overall design is identical to the Seiko 4L/6L family movements, though the finishing and some movement details are quite different.
Although a Japanese design, it includes many signature Swiss features, including Incabloc Double-Cone shock absorbers and an oscillating pinion automatic winding switcher. It is exactly the same size as the ETA 2892A2, with the same locations for dial feet, crown, hands, and date window. This makes it a drop-in replacement when that movement is unavailable.
Soprod A10 Family History
Seiko Instruments first designed their Cal. 4L family to create an ETA 2892A2 competitor for the Swiss OEM market. It appears that it was not intended for use in Seiko products initially.
SFT subsidiary, Indtec SA, announced their Swiss Made version, “Alternance 10” or “A-10”, in 2004 and began offering it to Swiss watch makers. The company was not explicit about the design source of the movement. The company took the Soprod name shortly after, with the movement commonly called “A-10.” In 2007, Soprod was acquired by Peace Mark of Hong Kong for the company’s quartz movement operations in China, and the Swiss mechanical operations were sold to Festina Group the following year. Seiko introduced their own 4L25-powered Brightz and Credor models, though the 4L family remained rare and was retired after 2013. Soprod continued to produce the A-10 as well as many modules in partnership with Dubois-Depràz.
Soprod redesigned the movement and announced the updated and renamed Cal. A10-2 in 2012. At this time the company also reworked and renamed the module series to differentiate their products from the simpler offerings of the competition. The A10-2 was renamed Soprod M100 in 2016, along with another refresh of the modular offerings.