DC 67 vs DC 67 Si
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  1. #1
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    DC 67 vs DC 67 Si

    Due the upgrades to the movement result in reduced servicing frequency?

  2. #2
    Moderator German Watches Forum
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    Re: DC 67 vs DC 67 Si

    Quote Originally Posted by Schmiedel View Post
    Due the upgrades to the movement result in reduced servicing frequency?
    The Valjoux 7750 has been reliable and pretty accurate. So, maybe
    we have to wait longer to know. The Si escapement should provide
    better life time and eliminate timing issues of magnetization. I don't
    have the Si escapement. I wish I did. Is is worth €700 ? If you can
    afford it I would seriously consider it. Damasko was an early developer
    of the Si escapement, and the high end watches seem to be switching
    to at least the silicon balance spring.


    Thanks,
    rationaltime

  3. #3
    Member Will_f's Avatar
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    Re: DC 67 vs DC 67 Si

    Possibly, but I wouldn't bet big money on it. Might be more accurate though.
    Owner of a bunch of cool watches.


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  5. #4
    Moderator at Large stuffler,mike's Avatar
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    Re: DC 67 vs DC 67 Si

    Not necessarily, The SI spring however is an improvement re accuracy. Here's what Damasko published:


    Isochronism constitutes the essential element of any chronometry, which itself is based on oscillations of whatever kind, such as the oscillations of a pendulum, a quartz crystal or a balance. The more regular the oscillation, the more regular the chronometric performance of the movement and the better it can be adjusted for best possible accuracy. If a control mechanism oscillates perfectly evenly, it is called isochronous (Greek for “occurring at equal intervals”). In this context, the isochronism of the classical balance of portable mechanical watches has emerged as the greatest challenge for watchmakers and engineers. Major interference factors are primarily:

    - the asymmetric development (transient and dying out oscillations, e.g. breath) of the spring,
    - the changing elasticity of the spring depending on temperature,
    - the influence of magnetic noise fields,
    - mechanical and thermal material changes at both fixation points of the spring,
    - the influence of the centrifugal and gravitational forces on the spring,
    - the imbalance of the balance wheel,
    - the play between the regulator pins.


    The properties of the EPS® material alone do not suffice to solve the phenomenon of asymmetric development of a flat spiral spring. Our research team was therefore looking for a solution and found it in a new type of end curve design that could be realized within the oscillatory level of the spring. This is shown in a conspicuous thickening at the outer end, which forces the EPS® spring into a concentric development, making the transient and dying-out oscillation take place symmetrically to the centre of the spring on all sides of the oscillatory level. This ideal form of thickening was registered as a patent.

    The EPS® spring is manufactured in one piece, which means it has an integrated collet for fixation to the balance shaft and at the outer end it is “clipped” into a very precisely defined area in the stud. The minute clamping jaws of this stud are designed to be resilient so that the clip-on point of the spring may still be corrected by pulling or pushing the spring through the stud. This new type of stud was registered as a patent.

    On conventional springs, the inner end is affixed to the collet by soldering, welding or clamping. This causes a structural modification of the spring material at the fixation points due to squeezing or heating, which in turn requires additional adjustment work.

    With our EPS® spring we have created an oscillating mechanism that provides several key advantages: The EPS® spring oscillation is ideally concentric. It is designed for isochronism independently of temperature, position of the movement and magnetic fields.

    As in the case of the silicon escape wheel, the EPS® spring is produced in a DRIE etching process (Deep Reactive Ion Etching), which is described in more detail at a later stage. The material has a uniformly flawless polycrystalline structure and can be machined in the micrometer range. As a result, all EPS® springs are of consistently uniform and extremely high quality, which is in turn transferred onto the chronometric accuracy of the movement fitted with these.

    The EPS ® spring reflects the consistent innovative policy of our manufactory. With this development, Damasko moved to the forefront of innovation and simultaneously sets decisive accents in order to endow their new products with a brand-specific exclusivity through significant distinguishing features. As in the case of the EPS spring, the aim of this innovative philosophy is to further increase the chronometric accuracy and stability of mechanical watches as well as the longevity and sustainable value of Damasko watches.
    Kind regards
    Mike


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  6. #5
    Member CitizenM's Avatar
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    Re: DC 67 vs DC 67 Si

    More importantly, it looks cooler with those sweet red accents:



    The silicon hairspring ought to contribute to the stability of the watch, mainly with reference to position and shock (not toughness, but change in accuracy due to shock). Some have suggested that due to the ability to control the shape of a silicon hairspring (varying thickness etc) isochronism can be improved as well, although others say a Breguet overcoil, which has not been duplicated (but Breguet does have a good imitation, I'm not sure if it performs as well as the "real" Breguet overcoil as the silicon variant is substantially different) in silicon is a bigger improvement there, so in my opinion, isochronism of a well made silicon hairspring vs. a good metallic is yet unknown (to consumers). Although the 7750 uses a flat hairspring anyway, so it's not exactly bringing the metallic hairspring's A-game in the first place, and in this case, should be an improvement--I just don't know how big in terms of isochronism. I also think the effect of temperature on silicon hairsprings has been inadequately discussed in the industry and it's odd to me that none of these companies make precise claims with resistance to temperature. Early studies by Ulysse Nardin suggested that their experimental silicon hairspring was actually substantially more susceptible to temperature related instability, although that was over ten years ago and it was just a prototype, so it's totally possible that they've addressed this by now. Still, I want to see some tests on this.

    Anywayyyy yes get the Si. Mostly because it looks cool and is more interesting.

  7. #6
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    Re: DC 67 vs DC 67 Si

    Thanks for the replies fellas. I was under the impression that the Si versions have other improvements to the movement, like maybe ceramic bearings. I was wondering if some of the othe movement modifications improved maintenance frequency requirements.

  8. #7
    Member Nokie's Avatar
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    Re: DC 67 vs DC 67 Si



    Very nice looking watch.
    "Either he's dead or my watch has stopped"
    Groucho Marx

    "The only reason for time is so that everything does not happen at once..."
    Albert Einstein

  9. #8
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    Re: DC 67 vs DC 67 Si

    Quote Originally Posted by Schmiedel View Post
    Thanks for the replies fellas. I was under the impression that the Si versions have other improvements to the movement, like maybe ceramic bearings. I was wondering if some of the othe movement modifications improved maintenance frequency requirements.
    According to Damasko, they do use ceramic bearings for the rotor and they adjust it in 5 positions. So it should be a step up from an ordinary 7750. The ceramic bearings and the EPS spring may contribute to the longevity of the movement, but I would imagine the service intervals for the Si 7750 will be the same as a normal 7750.

    Also, I forgot to mention, but Damasko lists the Si 7750 with a "weight balance wheel," which I can only assume means a free sprung balance like on their in house movements. With the addition of a free sprung balance and silicon hairspring, stability could be substantially improved.
    Last edited by Timeless Luxury Watches; May 16th, 2014 at 19:29.

  10. #9
    Member CM HUNTER's Avatar
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    Re: DC 67 vs DC 67 Si

    I would still have it serviced every 5-7 years. That's a long time in the grand scheme of things. It's a mechanical product and it should be treated as such regardless of the innovative improvements.

  11. #10
    Member ahkeelt's Avatar
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    Re: DC 67 vs DC 67 Si

    Quote Originally Posted by rationaltime View Post
    ......the Si escapement. .... Is is worth €700 ? .......


    Thanks,
    rationaltime
    ^ That is a Euro 700 question which I answered as a negative when I got my 67. Without the red, its still cool, I believe.

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