# Can someone fill me in about the ETA A07 231 movement?



## Illusion (Sep 17, 2006)

*Can someone fill me in about the ETA A07 231 movement? (New Valgrange Chrono mvt.)*

I saw a particularly nice Longines Master Collection Chrono with a nice subdial layout, the watch looks really nice imo. Was checking out the tech specs and its movement is listed as an L696 Longines Calibre (or ETA A07 231)

Can anyone tell me more about this movement? Is it based on the more common 7750 for example and have there been any issues with it?

I managed to dig out some operating specs as well

L696 Longines Calibre
Frequency 28'800 A/h
ø 16½''' - 36.60 mm
Height 7.90 mm
Winding Automatic
Power reserve 46 hours
Accuracy - 5 +15 sec./day
Base calibre ETA A07 231
Jewels 25

Thanks! 

Ed


----------



## JohnF (Feb 11, 2006)

Hi -

It is the new Valgranges movement, one that takes advantage of the trend towards larger watches to put a larger movement inside. From what I've read and seen, should be an excellent performer that puts the 7750 in its place. Autowinding, very long reserve energy for the movement (the power curve is very smooth), and a calibre that lends itself very well to customization by the watchmaker, i.e. in Chopard it is then adjusted for 6 positions and isochronism as if it were one of the classic calibres of the 1960s.

One watchmaker I talk to is very, very enthusiastic about the calibre, citing how robustly it is built and how good it retains adjustment.

JohnF


----------



## Illusion (Sep 17, 2006)

Hi John,

Thanks for the insights!  I did some googling and the base reference no. is actually 211, I guess the 231 is just a variant of some sorts. Gonna trawl the net for more info.


----------



## Illusion (Sep 17, 2006)

I have been trawling the net for more info on this Valgrange Chrono movement, but I think its still too new in the market. Will be checking with the Deja groups too.

If anyone has handled this new movement, could you share your opinions if its more of a slight incremental evolution from the 7750 (to better accomodate larger cases as seems to be the current trend) or if there have been any significant changes to the mechanism?

Thanks!


----------



## JohnF (Feb 11, 2006)

Hi -

No one really complains about the 7750 - efficient winding mechanism, even if only one-sided, fairly robust, solid time-keeping quality, especially in the higher quality versions - but the design is getting on and ETA wanted to use the trend to its own advantage.

I posted this on 20 May 2006 on the old forum (we had this crash...): Chronos, a watch magazine in Germany, tested the Chopard Mille Miglia...

_ Chopard Mille Miglia Gran Turismo XL, COSC-certified with a 46-hour reserve, adjusted to 5 (five!) positions, with the following results in the magazine Chronos 1/2006: Face up 0 seconds, face down -1 s., crown up +4 s., crown down +4s, crown left +2s, crown right +5 s. with middle amplitude flat of 294° and vertical of 260°. Total timing difference of 6 sec. with middle deviation of +2 sec.

Their review said that the Valgranges is a massive work with extremely stable timing results. The Valgranges (A07.111) has a diameter of 16.5 lines, 7.9mm height, 24 jewels, Nivarox hairspring "Etastable", 28'800 bpm, etachron regulation, single main spring and one-sided automatic system (i.e. the rotor only winds when it moves clockwise). The caliber is based on the 7750, but the 7750 is only 13.25 lines, so this is considerably larger (16.5 lines is 37.22 mm).

Chronos liked the caliber so much (it can use many parts of the 7750 for repairs) that they felt it will probably be one of the most dependable calibers that ETA has ever manufactured, and with the COSC certification and the kind of results that at least Chopard was able to achieve, one with excellent accuracy._

You're right that there isn't much available on the finer design points. I'd absolutely LOVE for Mr. Odets to write up one of his invariably superb reviews on the calibre. In lieu of that, consider this:

A) the increase to 46 hour power reserve means several things. 
First, you have more power to play with when adding complications; second, the power curve of the spring will also have a longer linear portion, which invariably increases accuracy.

B) There's room on the movement for the watchmaker to get down and funky with. Add a swan-neck regulator on a 7750 can be done, but it's tight, and on the A07 you've simply got more real estate to work with. Adding customized work is simply easier with a larger movement.

C) ETA is doing its horological homework and knows that watchmakers are having difficulties selling $10k watches with the "same" work as a $2k watch, all other things being equal. Making the base movement a tad larger means that it will run, all other things being equal, more smoothly, since you are increase the mass of the moving parts. Think of the old record players: some of the substantial price differences among, say, Thorens models were based simply on the weight of the platter that the record revolved on and the motor to drive it (I'm simplifying, but that's the basics), and I've known audio freaks who weighted their records down and let the record player run for 20 minutes so that the speed would stabilize to an immeasurable variation before they'd put the diamond on the vinyl. To increase the accuracy of the seconds count (NOT the beat!) you can either increase the weight of the balance wheel or you can increase the speed, with speed ultimately winning out up to the mechanical limits.

The ETA A07 series has been described as the 7750 on steroids, which isn't that far off. But consider one camera I use, the Pentax 67, which has been described as a Pentax Spotmatic on steroids (it's a 6x7 cm medium-format SLR with a dual bayonet mount, considered to be one of the true workhorses of the photo industry, even with today's digitals, as that huge negative when drum scanned gives you roughly a 130 MP image!). Also true, but that Pentax is the longest-running production model of any camera made: it was first offered in 1967 and is still being made today, albeit with a tad more electronics inside than in the beginning.

Now, if anyone wants to give me one to play with (and a timing machine!), I'd be willing to take a week off of work to write a right down proper review... 

JohnF


----------



## Illusion (Sep 17, 2006)

John thanks for the excellent insights!  I like how you use that pentax 67 analogy, that indeed is a real workhorse medium format camera!


----------



## rfrazier (Feb 21, 2006)

JohnF said:


> B) There's room on the movement for the watchmaker to get down and funky with. Add a swan-neck regulator on a 7750 can be done, but it's tight, and on the A07 you've simply got more real estate to work with. Adding customized work is simply easier with a larger movement.
> 
> JohnF


Some older movements come in two sizes, e.g., 10 1/2 and 11 1/2 ligne. But the difference is simply in the size of the plates, usually with an extra slanting bit on the outside. So, there isn't actually any extra room for anything interesting. It is more or less like a built-in spacer. If the Valgranges is simply a resizing of the Valjoux movement, won't it be similar in this way?

Best wishes,
Bob


----------



## JohnF (Feb 11, 2006)

Hi -

Can't say for sure, as I don't have a 7750 or a A07 in front of me to compare. But the jump to 16.5''' from 13.25''' is more substantial than the jump from 10.5''' to 11.5''' (9,5% increase as opposed to a 24,5% increase).

While many parts of the 7750 can be used on the Valgrange, not all can. Like I said, I don't have one in front of me to compare (where's Walter Odets when you need him????).

JohnF


----------



## rfrazier (Feb 21, 2006)

It is surprising difficult to get a good, high resolution picture of the movement. Here is a largish one. Look at the position of the screw for the balance cock, and the location of the balance cock itself. (This is the A07 171.)










Best wishes,
Bob


----------



## lysanderxiii (Oct 4, 2006)

There looks to be a lot more real estate to work with on both sides


----------

