Sinn 6000 Roségold with refined Valjoux 7750
The 7750 is derived from the manually-wound Valjoux 7733 chronograph movement, itself a descendent of the Venus 188, a company Valjoux purchased in 1966. It was designed (partially on computer, an industry first) by Edmond Capt.
Introduced on July 1, 1974, at the height of the quartz crisis, the 7750 was released five years after the race to build an automatic chronograph was won by Zenith's El Primero and the Chronomatic consortium. It sold well initially (estimated at 100,000 pieces in 1974) but was doomed the very next year. Production stopped in 1975 but demand was so low that supplies lasted into the 1980's. Local management retained the dies and equipment, allowing them to restart production in 1985 as demand for automatic watches rebounded.
Thanks to a durable and inexpensive design and strong support from Swatch Group, the 7750 has become the most common Swiss automatic chronograph movement. Since the takeover of Valjoux by ETA the movement is also called ETA 7750.
This calibre is still produced and is probably the most successful automatic chronograph movement of all times. It serves as basis for several superstructures or modules, including many from other manufacturers. Due to its accuracy and robustness it can also be certified as chronometer. So the manufacturer Breitling, for example, sends all of its watches, including numerous models with the Valjoux 7750 to the COSC certification.
These movements are currently referred to as “ETA 7750” or “Valjoux 7750”, but ETA officially calls them “7750 Valjoux” to differentiate them from the Valgranges line. As of 2019, ETA produces the 7750, 7751, 7753, and 7754 as well as the derived ETA A05 line for Tissot and Rado and the larger Valgranges A07 line.
The 7750 is a self-winding chronograph movement with 25 jewels, ball-bearing rotor, unidirectional winding, 1/8-seconds counter, 30-minutes counter, 12-hours counter, 28.800 A/h, power reserve ca. 44 hours.
The key distinguishing features of the 7750 family are as follows
- Subdials at 6 00, 9 00, and 12 00 for hours, running seconds, and 30 minute chronograph counter, respectively
- Calendar plate with modular components
- Top plate with additional winding bridge
- Etachron regulator and balance spring stud
The initial 7750 movement used 17 jewels, but current versions of the 7750 have 24 or 25. It has been supplied at both 21,600 or 28,800 beats per hour, though the latter is much more common.
ETA produces 7750 movements in three finishes
|Winding||Model||Year||30 Minute Chrono||12 Hour Chrono||Special Features|
|7751||1986-present||Yes||Yes||Full calendar with hands date, moon phase, 24-hours indication|
|7753||2002-present||Yes||Yes||Minute counter at the 3 instead of the 12, date change by pushers at the 10|
|7754||2003-present||Yes||Yes||GMT function on additional 24-hour hand|
|7757||1985-2003||Yes||Yes||Regatta countdown indication|
- Valjoux 7750 (1973-present)
- Damasko (fitting a Si main spring to the 7750)
- Fortis, developed by Paul Gerber featuring an alarm and two springs
- Franck Muller FM 7850 CC MB
- IWC Cal. 7922, 79320
- Jacques Etoile (cal. IV.C4)
- Omega 1155 (17 jewels), 1152/1154/1156/1158/1164 (25 jewels)
- Paul Picot “Atelier Technikum”
- Revue-Thommen (“Airspeed Flyback”)
- Sinn (“Flyback”)
- Column wheel variants
- ETA A08.L01/A08.231 for Longines (Cal. 688, 788)
- Hours, minutes
- Small seconds at the 9
- 1/8-seconds counter, 30-minutes counter, 12-hours counter
- Rapid calendar advance
- Since 1973