When we first heard of the Rudis Sylva Harmonious Oscillator at REVOLUTION we were pretty skeptical as it seems to fly in the face of one of the most sacred of all horological commandments: Thou shalt not mess with the oscillator.
The Harmonious Oscillator is one of a still somewhat small family of complications which try to go the tourbillon one better –that is, they attempt (with varying degrees of success) to address the problem of positional variation in rate. This is the problem the tourbillon was invented in an attempt to solve, but a few instances of spectacular performance by tourbillons in chronometry competitions and, in the Olde Days, observatory time trials, notwithstanding, the tourbillon still has detractors who insist that it solves nothing.
Without entering an opinion in that particular debate (we don’t, despite years of following the various pro and con arguments, feel qualified to have one) we would like to offer the work of the new firm known as Rudis Sylva for your consideration.
Rudis Sylva (the name is not that of a person, but an allusion to the woodlands surrounding the village of Le Bois, near the firm’s headquarters) was founded by Jacky Epitaux (formerly of Zenith, and R&R Holdings, which once owned Rodolphe Watches) and the idea for the Harmonious Oscillator is that of one Romain Gillet, with the concept being made real by watchmaker Mika Rassinen, a Finnish complications specialist. The Harmonious Oscillator is a unique 60 second tourbillon with two balances. Only one balance –the driving balance –is driven by the escape wheel and lever. The other –which one might call the “regulating balance” (a coinage we’ve made for clarity’s sake; it’s not an official Rudis Sylva term, we hasten to emphasize) is geared to the driving balance by gear-teeth cut into the rims of each balance.
“Driving” Balance, With Bridge For Balance Wheel And Lever Visible Below
The idea is simple –the two (non-overcoil) balance springs are attached at opposite points, and their symmetrically opposed breathing is intended to cancel out positional rate variation, which results from the asymmetric breathing of conventional balance springs. Rudis Sylva also asserts that the two balances will exhibit a “resonance effect” –the advantage here is presumably that of any other resonance watch or clock, which is greater stability of rate.
The idea seems sound and while there are other double balance spring watches this is the only one we’re aware of with two mechanically coupled balances as well. The closest watch to the Harmonious Oscillator we’re aware of is the Resonance Tourbillon by Beat Haldemann (as reported on the occasion of its launch on ThePuristS.com) which has two balances and two remontoires on the escape wheels –all mounted on a tourbillon carriage; the Haldemann design features two mechanically coupled balance springs, rather than two mechanically coupled balances.
The problem is that for the entire history of horology, the most significant evolutions in escapement design have been those which leave the oscillator as “free” as possible –that is, the escapement ideally should give impulse to the balance in such a way as to have as little physical contact with it as possible. The verge and cylinder escapements, the two earliest watch escapements, are both “frictional rest” escapements in which the balance is in constant contact with the escapement, and this friction produces significant rate variations; it is the superiority of detached escapements –like the lever, chronometer detent, Robin, and Daniels Co-Axial escapements –which made frictional rest escapements obsolete.
The fact that two balances are mechanically coupled with each other seems at first blush like a perfectly terrible one –however, the mechanical interaction in the Harmonious Oscillator is between two balances rather than between a balance and an escapement. We’re still not sure the notion is a sound one as we can think of several hypothetical issues with this design –“noise” in the oscillator system from asymmetry in the poise of each balance, from anything less than perfectly concentric balances or perfectly formed teeth, as well as frictional variations from the interaction of each balance with the other (which would not be present in a conventional resonator watch, in which the balances are not geared to each other) could all diminish or negate the theoretical advantages of the Rudis Sylva design.
There’s no doubt, though, that it’s a stunningly beautifully made watch –the elaborate finish is as high grade as we’ve ever seen, with beautifully polished steelwork in the tourbillon cage, for instance, showing the sharp, hand-polished internal corners that are a signature of true hate de gamme finishing. While we still think the jury is out on the practical advantages of this design –Rudis Sylva has not released any actual figures for performance –we do think an open mind is warranted, and if the execution and adjustment of the system is precise enough —it could work.