The JLC 815 is the first automatic alarm movement from Jaeger-LeCoultre.

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

• An interesting page of JLC history: Automatic watches
• Modern Classics: Jaeger-LeCoultre Memovox
• A Little Potted History Of The Memovox & My Recently Acquired Cal 911