Question re a Sinn EZM10


Does anyone know if the chronograph/stop-watch function on a Sinn EZM10 can be used as a duel time function.

If, for example, I was going to a time zone with a 2 hour difference could I set the chronograph to start at 12:00 when my watch was at 10:00 and simply leave the timer on and use the watch's orange dial to tell me the time while I was away?

The only problem I can foresee is that the orange dial stops after 12 hours but I don't see why it should.



Interesting question, and I did not find a definitive answer.
06/03/2015 - 20:35

Everything in me says "don't do that", but all the objective information doesn't seem to support that gut reaction.  Power reserve on Tag Heuers seems to drain at about a 10-20% faster rate, according to documentation.  It seems odd that they would make the parts out of anything less robust than the movements "regular" gear train, etc.  I just don't know.  My heart says "no", but my brain cannot back that up.  There are far more knowledgeable people (some who own Sinns), so maybe they will have better guidance for you.

Re: Interesting question, and I did not find a definitive answer.
06/03/2015 - 21:03

So far I've got a 'no way' and a 'sure' so I think I'll put your 'don't do that' in the 'no way' column and not do it.

But, on the other hand, why have the chronograph measure 12 hours if it shouldn't be used very long? 



Advice to a fellow Sinner...
06/03/2015 - 23:43

I suppose one could read two questions into your query.  You could use a chronograph to mark a second time zone if you have a 12hr totalizer, and a rotating bezel for a third.  You'd have to make a mental note whether your other zones are same am/pm as the primary.

Should you run the chronograph constantly to track a second time zone is another question.  Your watch has a Valjoux 7750-based movement which will lose amplitude when the chrono is running, and therefore accuracy.  One source suggested 20 degrees!  Other calibers with integrated chronograph mechanisms are less affected and it has been said the chrono function of the F. Piguet 1185, as found in the Overseas, can be safely run without affecting timekeeping.  Indeed my Blancpain QP needs to have the chrono running for seconds indication. 

Walt Odets did one of his usual fine dissection of a 7750 at TimeZone and suggested that service is critical to continuous running due to its cost-conscious design.  OTOH, many users have upgraded from the base movement so it may depend on the brand.

Found some rate results
06/04/2015 - 02:27

WatchTime, April 2015, published a review of the EZM10 including rate results over 24hrs.  First numer is with chrono off, second with chrono running:

Dial up           +6 +4Dial down      +8 +7Crown up      +4 +5Crown down +6  +6Crown left      +7  +5Crown right    0 +1Greatest deviation of rate   8 6Average deviation    +5.2 +4.7Average amplitude:Flat positions            326° 304°Hanging positions   262° 243°

So indeed, the amplitude dropped by about 20 degrees with the chrono running.  The overall results, however, were also better with the chrono running.  I think this can be explained because during that condition, the amplitude of 304 degrees flat and 243 degrees hanging are within the ideal ranges, while normal running produced an excessive amplitude surprise.  If this is typical for the EZM10, the factory is regulating it to perform best with the chronograph running.  Thanks for bringing up this most interesting topic.

Re: Found some rate results
06/05/2015 - 01:10


Wow! That is interesting! Most people I've asked told me that leaving the chonograph running greatly reduced the accuracy of the watch but this is certainly not the case for the Sinn and I couldn't see why it would be. I just couldn't see why, if there is a total of 12 hours on the cumulative dial, it would matter one whit to the watch if the chronograph was left on or not. 

I am very proud of the fact that I actually figured out how one could use the moveable bezel to use the watch in another time zone. If there was a 6 hour difference perhaps one could use a system of mirrors...LOL

I will have a look at that WatchTime article as well and thank you for taking the time to reproduce it for me. Your table was a little garbled until I went to the 'reply' page where it became abundantly clear.

I wish I'd had this watch when I flew.

Thank you, again, for taking the time to do this. Greatly appreciated! Sorry if my reply is a little late - I've been away.