Hello. In a recent magazine article about index versus freely oscillating balance springs, the AP calibre 3120 is discussed. The magazine illustrates two balance springs used, and a quote by Georges-Henri Meylan, AP, mentions the use of a balance with one or two freely swinging balance springs. Can any members comment on this? The excellent article on the 3120 "pre series" by Mr. Suitbert Walter doesn't seem to address this, and I would be very interested to know if all or some of the 3120's in the 15300 use two balance springs. I wonder, too, if other movements use two balance springs, and how this might affect the performance and adjustments of the movements. Thank you.
Unfortunately, I don't have a strong grasp of the technical aspects of watchmaking, but I very much enjoy watches and learning about them. Here is a gratuitous picture of my Royal Oak.
