Author Topic: Valjoux 7750 - timekeeping accuracy? (Read 22037 times)

kltime · « **on:** July 15, 2011, 01:09:03 PM »

Watch kaki bros,

In between looking at the pile of work on my desk,took a break to surf MWF and this site which is the Malaysian standard time maintained by SIRIM :

http://mst.sirim.my/index.php

Took the chance to test the accuracy of what I was wearing for the day, my Ball Fireman Ionosphere chronograph. Movement is the Valjoux 7750, which is a quite common movement for other brands that does not manufacture in-house movements.

After 1 day , it was approx. +3 which I thought was quite good since this is non COSC certified. Four n half days later ( after not wearing in on the 3rd day ) its about +25.

Anybody want to share or test your valjoux 7750 performance for comparison sake? I am curious since as I hv said, this is a tried and tested movement.

hanz079 · « **Reply #1 on:** July 15, 2011, 01:48:17 PM »

Since you gave the link and all, I have synchronized my Damasko D67 which is a Valjoux 7750 powered....
I will chk back tomorrow morning to see the accuracy...

G.MAC · « **Reply #2 on:** July 15, 2011, 01:52:15 PM »

I'll check my Glycine Black Jack Chrono and report back..

takashi78 · « **Reply #3 on:** July 15, 2011, 02:09:06 PM »

i would suggest avg it out over 1 week to be sure.
And make sure to wear the watch everyday.

hanz079 · « **Reply #4 on:** July 16, 2011, 09:09:24 AM »

Day 1.

My Damasko is at +5
Since last night I rested the watch at the crown up position, I will try tonight at crown down position to see if it will be slowed down to balance it...

A little off topic, I also sync my Dad's Exp2 and it came out at +-0!! Spot on accurate but like Peter said, will chk in a week and in a month to see if its stable.

kltime · « **Reply #5 on:** July 16, 2011, 10:08:09 PM »

Day 1 results +3 and +5.

I am also going to test my ML Pontos Chronographe next.

hanz079 · « **Reply #6 on:** July 17, 2011, 08:24:31 AM »

Day 2

Rested the Damasko crown down last night and after checking today, still running at +5... so now total is +10 for 2 days.
Will try to rest the watch in different position again tonight to see if there are variations.

My Dad's Rolex Exp2 still running at +-0!!

engkow · « **Reply #7 on:** July 17, 2011, 09:20:37 AM »

my sinn 303, bought last month from scott, wear from 7 am till around 10 pm then take off
put on dressing table face up, wear for around 3 week -4 to -10 second per 24 hours.
i will try other position and will update.

besview · « **Reply #8 on:** July 17, 2011, 12:03:22 PM »

My IWC pilot chrono still runs + 2 sec after all these years...non Chronometer some more.

hanz079 · « **Reply #9 on:** July 18, 2011, 06:41:06 AM »

Day 3.

Rested my Damasko crystal down last nite.
Checked it an still +5... for a total of +15 over 3 days...
Looks to be running fast but at a stable rate.

kltime · « **Reply #10 on:** July 18, 2011, 08:44:24 AM »

From ETA SA wikipedia page- 7750 hv 3 grades :

"Elaborated grade is adjusted in four positions with an average rate of +/-5 seconds/day, with a maximum daily variation of +/-20 seconds/day;the Top grade is adjusted in five positions with an average rate of +/-4 seconds/day, with a maximum daily variation of +/-15 seconds/day.The Chronometer grade must meet strict standards prescribed by the COSC: an average rate of -4/+6 with a maximum daily variation of +/-5 seconds/day."

Seems to be correct as claimed so far...

hanz079 · « **Reply #11 on:** July 19, 2011, 07:21:44 AM »

Day 4.

Rested my watch crystal up last night and it's running at +5 again for a total of +20 over 4 days...

G.MAC · « **Reply #12 on:** July 25, 2011, 08:57:42 PM »

after 2 weeks, time gain is around 2 minutes so i am guessing it is around +9 to 10 secs a day.

kltime · « **Reply #13 on:** July 27, 2011, 11:37:31 AM »

Guys,

Anyone can refer me to a good reference article on the effect of the various positions ( crown up/down,etc) on accuracy?

TheHobbit · « **Reply #14 on:** July 27, 2011, 12:31:33 PM »

Quote from: kltime on July 27, 2011, 11:37:31 AM

Guys,

Anyone can refer me to a good reference article on the effect of the various positions ( crown up/down,etc) on accuracy?

Hope this helps. It may be for Rolex, but the general view is that it applies to other watches.

kltime · « **Reply #15 on:** August 02, 2011, 08:15:13 AM »

TQ TheHobbit.

Anyway, now testing another 7750 - my Maurice Lacroix Pontos Chronographe. This one seems to be running a bit faster,tho still within specs. After 1 day , its about +10.

terrenceterrence · « **Reply #16 on:** August 03, 2011, 10:48:04 AM »

i have 2 Valjoux calibre watches; namely my Tudor Prince Date Chrono and Valgranges A07.111 on my Wempe Aviator (which is an oversized time, date and second hand only 7750 calibre for larger cased watches)

both are within COSC +-3 per day. Think they are like the old Land Rover Defender of watch calibres. Rough on the edges but built like a tank. Versatile and dependable. Winds rougher and you can really hear and feel the wobble.

but of course it's still not a Lemania 5100 in terms of "bullet proofness"

kltime · « **Reply #17 on:** August 04, 2011, 02:24:05 PM »

Quote from: terrenceterrence on August 03, 2011, 10:48:04 AM

both are within COSC +-3 per day. Think they are like the old Land Rover Defender of watch calibres. Rough on the edges but built like a tank. Versatile and dependable. Winds rougher and you can really hear and feel the wobble.
but of course it's still not a Lemania 5100 in terms of "bullet proofness"

Update - After 4+ days my ML Pontos is about +35. So its probably about +8 to +10 per day.
Like what terrence said, I suppose this is a tried and tested movement and that is wat makes it popular. Some pure in-house fans may look down on a so called common ETA based caliber but I suppose thats their choice to pay top $$.

JOS2012 · « **Reply #18 on:** January 11, 2012, 04:25:47 PM »

Accuracy and rate differs.
If your watch gains 5 secs exactly everyday then it is indeed accurate and you need to adjust the rate.
But if you watch runs fast differently everyday then it is not accurate of course taking into consideration the constant position as well as the winding state of mechanical watches if you want to have a really accurate test.
Even Witschi can only test your watch rate at the point of it being placed on the eqpmt.
The thing abt 7750s that I don't like is that when you pull out the crown to reset the hands, the hands moves slightly when the crown is pushed back in so the position of the hands is no longer accurate. I'm fastidious on the location of hands vizaviz the seconds...0 secs must really be in line with the minute markers 100%.
Others like the Cal 3313 (FP1185 based) or Lemanias don't have that problem.
GS Chronos are also fantastic in that aspect. The crown and stem is rock steady when you pull out and push in the crown with no movt of the hands whatsoever.
Not sure abt Zenith and current Daytonas...

sshark · « **Reply #19 on:** January 11, 2012, 09:43:54 PM »

Quote from: JOS2012 on January 11, 2012, 04:25:47 PM

...
The thing abt 7750s that I don't like is that when you pull out the crown to reset the hands, the hands moves slightly when the crown is pushed back in so the position of the hands is no longer accurate. I'm fastidious on the location of hands vizaviz the seconds...0 secs must really be in line with the minute markers 100%.
....

what I experienced something similar with Rolex cal. 3135. If I turned my minute hand anti clockwise and pushed the crown in to zero position the minute hand will jump fwd. OTH, if i turned the minute hand clockwise, it would not jump and zero in exactly as I left it.

JOS2012 · « **Reply #20 on:** January 12, 2012, 06:41:03 AM »

apart from the El Primero and the Rolex, I actually wondered whether those Vj7750 used in IWCs & Breitlings had this same problem or not as these 2 companies modifies quite a bit of the the standard ebauches parts for their watches..

As per your suggestion, yes I've tried moving the hands backwards then slowly back to the exact position as well as moving forwards then to the exact position but almost always the hands will shift slightly. On top of that you can feel some free play of the stem. This is not so for the Omega 3313 or the GS.
Maybe I'm too anal abt this kind of visceral stuff..

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Author Topic: Valjoux 7750 - timekeeping accuracy? (Read 22037 times)