3Flushes wrote: ↑
September 6th 2020, 1:49pm
Missed this one on the first go 'round.
I've been doing a lot of research on Longines for the last few months, specifically on the models with 7751 bases having missed out on the great SWI values years ago which I have lamented about around here adnauesiatingly. A cool moon phase chronograph has eluded me since, and I've settled on the latest Longines models and found the L688 while checking the '51 models out in hopes the venerable brand has a column wheel moon phase in the works. Nope.
Anyone using the breakout pressure required to actuate the chrono as the method to evaluate, and then entirely disparage this movement is completely ignorant of the intention and construction of the L688 specifically, and of the one universal obsession in watchmaking, in general. And while the L688 sure as hell ain't the 7750, it's certainly not the El Primero and beyond, either. And it wasn't designed to be.
Isochronism in a mechanical movement is the one universal thing in this thing of ours. It's the thing that inspired the greats who came first and it is still the only thing
in the very highest endeavors of watchmaking.
It's the thing that inspired great thinkers like Breguet to design the tourbillion, or Daniels to persevere in bringing the co-axial escapement to fruition and then to market. Interestingly, Daniels interest in improved accuracy was directly related to the introduction of quartz. It's also the thing that led Brequet to dump the tourbillion after making only 50 of the damn things because they were such abysmal timekeepers and professional embarrassments. The pursuit of perfect mechanical timekeeping is such that any minuscule advance whatsoever is cause for celebration and honor, and patents. And a price increase.
Human beings have been obsessed with the measurement and the passage of time since the beginning of our time, to the 100th of a second since 1916. Many refinements in chronograph movements were engineered from '16 through 1973 when the Japanese quartz invasion was launched. The 7750, the base of the oft maligned L688, was developed by Valjoux (ETA) in 1973 in direct response to the quartz invasion to compete with the Japanese threat.
The Swiss were suddenly competing against movements that were deadly accurate and cost a mere few dollars to produce. Switzerland needed a mechanical chronograph movement that would yield accurate timekeeping with forgiving tolerances to make manufacturing fast and easy, and much more economical. ETA used techniques like employing large plates instead of bridges that lots of shit could be attached to the bottom of, making the 7750 line highly configureable, and it incorporated the easier and cheaper to produce cam-lever, or cam switching actuating mechanism.
The V 7750 with it's snappy-poppy pushers and wobbling rotor motion, and the other 'lessers' of the cam lever design have the stigma of being the red headed stepchild to the column wheel movement given their humble ease and economy
beginnings, often bringing contempt onto the venerable 7750 and anything based on it.
So, primarily based on dismissive attitudes regarding the 7750 in general, psuedo-maven watch snobs miss the point of the L688 entirely as revealed in their complaints about breakout pressure and their resulting dismissal of the L688 in it's entirety without the slightest understanding what they are complaining about.
The 7750 definitely has crisp pushers that affirm engagement with a little pop at the end of their travel. I like the way the 77xx movements actuate; the reset has a very cool snap back motion and the action is quite distinctive from the mushiness of many column wheel movements, indeed. I associate the 77xx's with the stop/start action of a mechanical stopwatch.
The 'stiffness' of the 7750 pushers is attributed to the 'lesser' cam-switching system, so the mavens, having dented their delicate little fingertips after somehow having found the strength to actuate the L688, therefore misequivocate the stiffer action to the scorned cam-switching system of it's base, that isn't even there anymore
. This ridiculousness is then expanded into the false narrative that the L688 is a fake column wheel, and no better than the no good, in their opinion, 7750 of its foundation. Worthless other than the extended time reserve, of course, goes the usual piffle.
The point of the L688 was to produce a column wheel movement for those who 'get it' for a reasonable price which meant the movement would have to be as accurate as more expensive movements with more forgiving tolerances. Column wheel movements have to be made to much more stringent tolerances than cam-switchers which is where the cost and the pre-eminent mushiness comes in- lots and lots of teeny parts hand polished out of the cutter to those stringent tolerances- we've all seen the videos of the folks with the little sticks and fordham deals for hours, days, weeks, months, what ever it takes until it requires but a breath of air to engage the pushers and actuate the mechanism.
Given the forgiving tolerances and adaptability of the 7750 base, the L688 focuses on timekeeping enhancing modifications instead of agonizing over finishing. AIR, it has returned to bridges and reshaped the cam that engages ETA's design of the cam wheel turrets, which together, mitigate those tolerances elsewhere. The design also makes the turrets much less likely to break off when engaged. Column wheel movements are notoriously delicate and the L688 has indeed been a stalwart of robustnitude.
ETA also designed a double hammered reset mechanism, which, along with the above noted changes in the actuation mechanism are likely the source for the feel of the pushers, in addition to the lesser level of finishing. But polishing parts too extreme tolerances by hand is time consuming, a master craft, and therefore excruciatingly expensive. A lot of money for mushy pushers, so the L688 packs it into timekeeping.
Regulated proper in 5 positions in their 'master whatever' models, the thing delivers incredible accuracy well beyond the -4 to +6 specs AFA I could find in consumer reviews and industry writings. The L688 delivers consistent power through the entire silicone spring, is regulated by a 28800 Etachron escapement, sports a vertical clutch, and what am I forgetting goddammit - I know there's something else - oh yeah - 54 hours power reserve.
By prioritizing timekeeping and longevity over finishing, the L688 offers a column wheel movement with the accuracy and functionality perks for a fraction of the price of its agonizingly finished and higher beat, betters, with mushy pushers. However, if one wonders about the legitimacy of the column wheel credentials of the L688, one need only actuate the chronograph (if you have the digital strength) and watch the action and sweep of the chrono seconds hand. It's worth the comparatively modest price on the hangtags alone.