Valjoux 7750

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Breitling Chronomat Evolution with the 7750's familiar 6:9:12 subdial layout
Valjoux 7750
Breitling Chronomat Evolution, COSC certified
Sinn 6000 Roségold with refined Valjoux 7750

The Valjoux 7750 is a well-known and widely-used chronograph movement produced by Valjoux (part of ETA in the Swatch Group).

History

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.

Features

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
  • Conventional integrated center-mounted automatic winding in one direction (unlike the barrel-wound Chronomatic)
  • Cam-controlled chronograph functions using a "heart piece" (unlike the more complex column or pillar wheel style)
  • Simple three-plate brass base (rather than complex bridges)
    • Calendar plate with modular components
    • Main plate with off-center center wheel, hacking lever, and simple bent-spring ratchet
    • 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:

  1. Elaboré
  2. Top
  3. Chronomètre
Winding Model Year 30 Minute Chrono 12 Hour Chrono Special Features
Automatic 7750 1973 Yes Yes
7751 1986 Yes Yes Full calendar with hands date, moon phase, 24-hours indication
7753 2002 Yes Yes Minute counter at the 3 instead of the 12, date change by pushers at the 10
7754 2003 Yes Yes GMT function on additional 24-hour hand
7757 1985 Yes Yes Regatta countdown indication
7758 1985 Yes Yes Moon phase
Manual 7760 1985 Yes Yes
7761 1986 Yes No
7765 1983 Yes No Date
7768 1985 Yes No Moon phase

Movement family

Description:

Automatic chronograph
Escapement: stone lever
Yoke winding system
Stop mechanism: Cam switching
Glucydur balance wheel
Nivaflex mainspring
Incabloc shock protection

Functions:

Hours, minutes
Small seconds at the 9
1/8-seconds counter, 30-minutes counter, 12-hours counter
Rapid calendar advance
Hacking seconds
Complications: 12-hours counter, day: quickset date feature

Data:

13¼ lignes
D 30.0 mm, H 7.9 mm
25 jewels
28,800 A/h
Power reserve 44h

Production period:

Since 1973

External Links