Introduced in 1956 with the original Jaeger-LeCoultre Memovox (E 853), the Calibre 815 features a repeater alarm, the first in an automatic watch. This movement was later used in the Jaeger-LeCoultre Deep Sea Alarm (ref E 857) of 1959.
The JLC 815 spawned the similar JLC 825 which adds a date window and was introduced with the Memovox (E 855) in 1959. Production of Cal. 815 ended in 1966, while Cal. 825 was replaced in 1969 by Calibre 916, which featured a free-rotating winding mass.
Unlike earlier automatic movements from Jaeger-LeCoultre, the 815/825 features a central sweep second hand. It is a bumper movement like earlier JLC Calibres, however, since the alarm function had to reach past the rotor to the case back.
Calibre 815 had 17 jewels and measured 14 ligne across. It beat at 18,000 A/h. It was a dual barrel movement, with one barrel providing about 45 hours of run time and the other providing 20 seconds of alarm sound.
- 14 lignes in diameter
- Glucydur balance, automatically compensating flat hairspring
- 18,000 A/h
- Double barrel (time and alarm)
- Unidirectional bumper automatic winding for time
- Manual winding for alarm
- Direct sweep central seconds
- 17 jewels
- Alarm hammer inside case back
Jaeger-LeCoultre Alarm Calibres
- Manual winding
- 1951-1958 Calibre 489 (also P489 with Parachoc shock resistance) - screwed balance, dual top plates
- 1952 Calibre 601 - transitional model, fewer than 2,000 produced, with a single top plate
- 1953-1964 Calibre 814 - improved model (also Parachoc P814 and Kif K814) - screwed balance, single top plate
- 1962-1979 Calibres 910 and 911 - 911 added a date function, solid balance, dual top plates
- 1996 Calibre 914 - manual with gong
- Automatic winding
- 1956-1966 Calibre 815 - bumper automatic, 18,000 A/h; 825 adds a date function
- 1959-1969 Calibre 825 - Cal. 815 plus date function
- 1969-1983 Calibre 916 "Speedbeat" - free-turning rotor, 28,800 A/h, date, Kif only
- 1994-2008 Calibre 918 - updated 916
- 2007-present Calibre 912 - automatic, gong, 24-hour function
- 2008-present Calibre 956 - automatic, gong
- Specialty calibres