AP 2511

Calibre 2511 was one of the early quartz movements produced by Audemars Piguet.

Introduced in 1977, Cal. 2511 was used in the unusual rectangular Royal Oak line. It has 11 jewels.

Cal. 2511 was produced in the initial heyday of quartz movements, when the accuracy of this new technology was highlighted. Therefore, it has a highly unusual adjustment mechanism: The crown adjusts the hour hand when pulled, leaving the timekeeping and minute hand running. An inset pusher in the crown advanced the minute hand at intervals on demand, on the assumption that it would always be correct.

This movement was used at least through 1980 in the Audemars Piguet Royal Oak Quartz. It is round, even though it was used in rectangular watches and its predecessor was rectangular. The original battery was mercury-based, and replacements do not power the movement more than 12 months.

The similar Cal. 2510 used a separate pusher at 4:00 and was launched as early as 1974.

Manufacturer: Audemars Piguet Description: Second-generation quartz movement Functions: Central hour, minute, and seconds hands Hour hand and date adjustment using the crown in first position One-second corrector pusher inset in crown Data: 15 months battery life Accurate to +/- 1 second per month Production period: 1977-?