Mosaba was the marketing name used by ESA for their tuning fork movement, produced under license from Bulova between 1968 and the mid-1970s. ESA calibers included 9160, 9162, 9164, and 9210. These movements are also referred to as Swissonic 100, Speedsonic (Omega), and Ultronic (Longines), among other names.
The Bulova Accutron was tremendously successful from its launch in 1961. Ebauches SA was developing electric watches and experimenting with quartz technology but could not compete with the patented Accutron. In 1963, after designing the famed Accutron 214 movement, Max Hetzel left Bulova to design a similar movement for Ebauches SA. ESA licensed the Accutron technology in 1968 and put their updated version of the Bulova design into production almost immediately. The central component was named Mosaba for “Montres Sans Balancier” (“watch with no balance wheel”). These were produced as part of the “Swissonic” line as the “Swissonic 100” range.
ESA named these original movements Cal. 9160 (no date), 9162 (date), and 9164 (day/date). It was a 13 ligne movement with 12 jewels operating at 300 Hz. ESA used a “compensated” metal tuning fork which operated slower than the 360 Hz or 480 Hz Bulova. Cal. 9160 appears in print in 1968, with Cal. 9162 added in 1969, and Cal. 9164 in 1972.
ESA also produced a modular chronograph version known as Cal. 9210 by 1972. This was the first electronic chronograph movement, and the only tuning fork chronograph movement ever produced. The base movement is identical to the 9162 but a dial-side chronograph module from Dubois-Depraz is added. The module has its own day and date wheels, which rotate smoothly rather than jumping once per day. The complex chronograph module was designed specially for the tuning fork movement and features a vertical clutch for smooth engagement. The Chronograph had a 6-9-12 layout, with 12 hour counter at 6 00, 30 minute counter at 9 00, and running small seconds at 12 00.
Although well-designed and successful, tuning fork movements fell out of favor as more-accurate and durable quartz movements were introduced through the 1970s. The last company to use this movement was Technos, which the Technos Mosaba model in 1990, the last tuning fork watch offered for sale by any company. Just 200 were made using refinished original Mosaba movements.
- Certina “Certronic” Cal. 29-151 (date) and 29-152 (day/date)
- Eterna Cal. 1550 (date) and Cal. 1551 (day/date)
- IWC Cal. 150 (date) and Cal. 160 (day/date)
- Longines “Ultronic” Cal. 6132 (date) and Cal. 6332 (day/date)
- Omega “Speedsonic” Cal. 1250 (date), Cal. 1255 (chronograph), and Cal. 1260 (day/date)
- Tissot “Tissonic” Cal. 2010 (date) and Cal. 2020 (day/date)
- Zenith Cal. 50.0 (date) and Cal. 50.5 (day/date)