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Seiko Twin Quartz Specs.

16K views 41 replies 11 participants last post by  Tom-HK 
#1 ·
Dear All,

Firstly I would like to thank Bruce et. al. for all their wonderful posts. I have noted some debate about the Seiko Twin Quartz models in the forum and if Seiko had "regular" production models that were spected to +-5 seconds per year. I have seen a number of different postings dealing with which production Seikos had this level of accuracy and thought it might be helpful to set the record straight.

First Seiko "high accuracy quartz" : 4883 +- 1 second a month. 1974
First Twin Quartz spected to +- 5 seconds per year: 9983 1978
Second Twin Quartz spected to +-5 Seconds per year: 9483 1981
Third Twin Quartz spected to +-5 Seconds per year:9681 1981

( the 9983 is model number, 1978 year of production )

All these were produced when Seiko had an internal competition between two different ways to regulate the Twin Quartz model. The JHQ method only was tuned down to +- 10 seconds and lost. All other twin quartz models, other than above, were spected at +- 10 seconds.

Last Astron Re-Issue.

And finally the version that is being discussed today.

When I have a bit of time I will post on the differences between the 9F and 8F series. Suffice it to say the 8F is considered within Seiko to be a much better movement than the 9F and much more stable and accurate. It was expensive to produce and parts of the design made it hard to fit into thinner cases. The 9F sealed 50 year "no maintence" module that is discussed here actually is used in a number of movements. The 9F movement is less resistant to temp and magnetic fields and costs about 30 percent less to produce the the 8F. The 9F is thinner, and used more common parts and the frame is used for a number of other movements and watches. The 8F is, without a doubt, the most robust high accuracy quartz movement ever made. But it is thick ( hence the better thermo performance).

The very high accuracy +- 5 second twin quartz movements above were extremely expensive to produce and were not robust in field use. Their biggest problem was they tended to get fried if worn in hot baths or shower rooms ( a real issue here in Japan where the harried salaryman has his watch with him in the afterwork Sauna to benchmark the last train).

Best, Thomas Polgar.
 
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#3 ·
...All other twin quartz models, other than above, were spected at +- 10 seconds...
Thomas, I don't want to argue but again your quoted statement is incorrect, according to the info you that can read here:
https://www.watchuseek.com/showthread.php?t=151004

We don't know much about Japanese quartz technologies as the manufacturers (Citizen and Seiko) are very secretive about their know-how. Could you please show us hard evidence about the accuracy figures you wrote in your post? (I mean similar technical manuals or any other reliable documentations to the ones you can find reading my link.) You might have the info and the evidence what we've been looking for.
 
#4 ·
I am not sure why you believe what you linked to indicates what I posted is not correct. The manuals you link to in no way contradict anything I said. The information I have posted comes from internal specs from Seiko in Japanese. I am really not that interested in "proving it" ( although the information is pretty much all over the net in Japanese) I just thought the forum would find it interesting. As for your assertion that Citizen and Seiko as "secretive" about their high accuracy quartz technologies, this isn't true either. Seiko isn't, Citizen is. The reason that Citizen is ( and hasn't patented the what is used in "The Citizen") is much of what they use was reverse engineered off the Seiko models I reference above ( i.e. the five second a year Seikos). The basic problem with the high accuracy Seikos is they cost about USD 500 more per year to make than they sold for, and cooked in hot baths. Seiko ditched them, and Citizen reverse engineered the line, and kept making them ( and also lose on each one made, but are trying to bridge the gap by boosting prices). The Citizens also seem to have licked the "cooking problem" with some more stable components.

Best, Thomas Polgar.
 
#5 · (Edited)
Hi Thomas. Welcome to the forum! :-! This is some very interesting information you've posted.

I don't think that George was challenging you in a negative way. Rather, your information illuminates some areas that we've all wondered about, and so he's eager to enter into discussion (as am I) and to learn your sources so that we can "study up" and try to reconcile it with other info we've gleaned. (In the Thermocomp article that George and I wrote, we were fanatical to include sources for our info, as we've seen some instances of mis-information being propogated on the Web.)

Let me go through your info with some questions ...

First, the competing regulation methods within Seiko is an interesting historical tidbit. (Just the kind that I -- as a confirmed electronerd -- like. :)) Were these literally just different procedures, and so either could be applied to any watch? Or was the choice of which one was used dictated by movement design? Any details of how either worked?

Second, it's interesting to hear about how the 9983, 9483, and 9681 differ from all the others. The claim has been made (in Carlos Perez's "Prometheus Bound" article on TimeZone) that Twin Quartz watches were spec'ed to 5 seconds per year, but the only manuals we've been able to find spec. 20 seconds per year. We had therefore assumed that this was an error in the article. (These manuals, btw, are why George was wondering about your statement of other TQs being spec'ed to 10 seconds per year, since the manuals spec. 20 seconds per year.) Do you have access to any of these manuals? We'd love to see them!

Third, your statements about the 8F vs. 9F do feel counter to all we've come to understand so far. (For one thing, the 9F is thicker than the 8F.) Might you have accidentally reversed them when referring to them?

Finally, interesting comment about Citizen's The Citizen. However, reverse engineering from a Twin Quartz feels unlikely to me. I say this because the movement (the A660) seems to have only one crystal, which operates at 32 kHz. This is what its manual says. Also, while I did not successfully get a statement of what its thermocomp scheme is, I did converse with a Citizen Japan engineer who confirmed that it has a single crystal. We've always assumed that the movement works via explicit temperature measurement coupled with digital count suppression.

Again, welcome aboard and thanks for the provocative info. Any source material you could share would be greatly appreciated!
 
#7 ·
Hi Thomas. Welcome to the forum! :-! This is some very interesting information you've posted.

I don't think that George was challenging you in a negative way. Rather, your information illuminates some areas that we've all wondered about, and so he's eager to enter into discussion (as am I) and to learn your sources so that we can "study up" and try to reconcile it with other info we've gleaned. (In the Thermocomp article that George and I wrote, we were fanatical to include sources for our info, as we've seen some instances of mis-information being propogated on the Web.)

Let me go through your info with some questions ...

First, the competing regulation methods within Seiko is an interesting historical tidbit. (Just the kind that I -- as a confirmed electronerd -- like. :)) Were these literally just different procedures, and so either could be applied to any watch? Or was the choice of which one was used dictated by movement design? Any details of how either worked?

Second, it's interesting to hear about how the 9983, 9483, and 9681 differ from all the others. The claim has been made (in Carlos Perez's "Prometheus Bound" article on TimeZone) that Twin Quartz watches were spec'ed to 5 seconds per year, but the only manuals we've been able to find spec. 20 seconds per year. We had therefore assumed that this was an error in the article. (These manuals, btw, are why George was wondering about your statement of other TQs being spec'ed to 10 seconds per year, since the manuals spec. 20 seconds per year.) Do you have access to any of these manuals? We'd love to see them!

Third, your statements about the 8F vs. 9F do feel counter to all we've come to understand so far. (For one thing, the 9F is thicker than the 8F.) Might you have accidentally reversed them when referring to them?

Finally, interesting comment about Citizen's The Citizen. However, reverse engineering from a Twin Quartz feels unlikely to me. I say this because the movement (the A660) seems to have only one crystal, which operates at 32 kHz. This is what its manual says. Also, while I did not successfully get a statement of what its thermocomp scheme is, I did converse with a Citizen Japan engineer who confirmed that it has a single crystal. We've always assumed that the movement works via explicit temperature measurement coupled with digital count suppression.

Again, welcome aboard and thanks for the provocative info. Any source material you could share would be greatly appreciated!

Dear Bruce,

Many thanks for your warm note. Firstly you have me out "electro-nerded" ( meant with good humor ) and some of what I am passing on I don't myself understand completely. I am going to have to be a bit mysterious with respect to who I am and why I know what I know ( to protect the innocent, as they say). I am very closely connected to the small fraternity of engineers in Japan who were involved in the development of Quartz watches in the 1970's and 1980's. My strength is access to the people and the language, not the minutiae of the technology. Keep in mind that my "sources" are slightly Seiko biased ( but there are a few retired Citizen folks as well ).

Dealing with your questions:

  • I don't know what the differences between the two regulation methods of the twin quartz movements was. One was named code named "JHQ" and the other, the winner, was something else. JHQ only could get down to + - ten seconds per year. I will see what more I can find on this.

  • People within Seiko are adamant "The Citizen" is ( or was ) a rip-off of the Seiko 9942. The 9942 was never spected down to + - five seconds by Seiko, but the same movement was spected down to + - five seconds by Seiko in other watches. Perhaps Citizen isn't being so "up-front" on whether they use two crystals ( I am guessing here, but "twin quartz the second" doesn't sound too good).

  • I think what may be confusing you is you are reading English manuals for the twin-quartz movements. Seiko always dumbed-down the specs for overseas watches to reduce servicing costs and complaints. The 9983 was the only watch Seiko exported with super accurate specs of + - five seconds. However they kept the same model number, but used a different English name. The specs I listed in my first posting are straight out of the Japanese language internal Seiko listing of high accuracy quartz movements. I would be breaking a confidence in posting a facsimile of it, but trust me, it is 100 % percent accurate and the watches do pop up in Japan for sale from time to time. All the Japanese sold watches had the + - 5 seconds per year specs in their manuals. The Seiko fellas do puff out their chests and say they were doing + - 5 secs per year before Citizen. My data is also very well supported by oodles of Japanese language "electro-nerd" postings.

  • On the 8F and 9F movements, I didn't transpose them. This is straight from the guys who designed them. Perhaps their definition of thicker is different than yours. The Seiko guys are universal is saying the 8F was the last "cost be damned" very robust movement they did. The internal feeling is the 9F is less robust, less accurate, less shielded, and, yes, they scoff at the lack of an independent hour hand.

Warm regards,

Thomas Polgar.
 
#6 ·
Welcome, Thomas! Looking forward to more of your posts.

I'm particularly interested in the Seiko 9F / 8F comparisons; and your mention of Seiko's in-house attitudes toward the (competing?) modules. That kind of thing is exactly the reason I enjoy this forum.
For me, at least, HEQ remains an enigma, wrapped in a riddle, and shrouded in mystery. (And that's only the English-language information.) :-s
I'm anxious to hear more.
 
#9 · (Edited)
What a wonderful post! I see the members are dissecting it diligently. Fear not, this is just the culture here! ... You should have been around when I suggested the Spring Drive was a derivative of the Auslab HPM ;-)

I may have a 9F movement coming but preliminarily I have to agree the 8F is a marvel, similar to the ESA 9162 in that the engineering is at a different level than most others... ADD NOTE: Well, he ment the 8J ... but I still like the 8F... accuracy that has a great cost effective payback.

ADD NOTE: the 9F came! I don't know if it works... if it does, I'll use it for testing... if it doesn't, I'll post pics of the disassembly! (Won't be quick though... many things in queue ahead of this).

I'm looking forward to more information. Thanks for participating!

PS... any data on how to adjust any of these movements without sending them back to Japan? Some can be intuited but some can't.
 
#12 ·
I still think the 8F is a fine example of good engineering ... accurate and cheap (kind of like the Datsun 240Z in the age of the MGB) ... but it all makes more sense now.
 
#17 ·
Well George, that wasn't the point I was making... but it is a very good point! :think:

I just got an Omega Calibre 1445 and was suprised when I downloaded the Owner's Manual to find the claim of +/- 10 seconds per year for an Eta Thermoline. We know it can do that but I was suprised to find it stated in writing... most folks choose to understate their claims. Well, the ones that hope to keep folks respect over the long haul do...
 
#19 ·
...I just got an Omega Calibre 1445 and was suprised when I downloaded the Owner's Manual to find the claim of +/- 10 seconds per year for an Eta Thermoline. We know it can do that but I was suprised to find it stated in writing...quote]

Congratulations, Jim, that's a day-date (with sub-dials) thermocompensated movement. Strictly speaking Cal.1445 (ETA 255.472) is not a Thermoline though it uses the digital inhibition scheme like the Thermolines however it has dual-oscillator vs single-oscillator + thermistor in the Thermolines. It can do much better than +/- 10 seconds per year with careful (and very simple) calibration.
 
#18 ·
I agree that the Twin Quartz was probably the only watch Seiko exported out of Japan that valiantly advertised its 5 SECONDS PER YEAR ACCURACY.

I remember going through old Nataional Geographic magazines from the early 80s advertising the 5 secs per year claim.

While at university in the early 90s in Hobart, Australia, I bumped into a watch maker who later became a good friend. He was one of the few quartz watach makers trained by Seiko in Japan.

He had a used twin quartz in his display and when I enquired about it he mentioned 20 secs per year accuracy. I then told him that it was specd to 5 secs per year but being a seiko man, he had no idea.

Hope this helps
 
#20 ·
I confess I don't follow the Japanese movements as well as others... I have some 8Fs and, as you can tell from my posts, I love them as great examples of cost effective HEQ.

I have a 9F but it's a bare movement and I don't even know if it works yet but Seiko and the forum appears to have liked it. I don't know the 8J... what is it used in?

(Thomas's statements appear to be at variance with a number of positions we have traditionally held. Evidently some of us strongly hold those positions... Please don't let that alter the civilized discussion on the forum. Thanks!)
 
#21 ·
Did any of the Longines VHPs use this movement? It is the only thermocompensated ETA I have found that has day as well as date... so I suspect Omega was the only user. But evidently it uses the same general inhibition scheme as the first VHP... right?
 
#22 ·
Did any of the Longines VHPs use this movement? It is the only thermocompensated ETA I have found that has day as well as date... so I suspect Omega was the only user. But evidently it uses the same general inhibition scheme as the first VHP... right?
Yes, the dual-oscillator ETA movements share identical electronic modules!
As far as I know, only Omega used that movement with the Constellation and the Seamaster (both in limited numbers). Be aware there is a non-thermocompensated version of this day-date design: Cal.1444 (ETA 255.471).
You're right: this is the only Swiss-made thermocompensated movement with analog day-date indication.
 
#27 ·
Thomas. Would it be possible to ask your Citizen friends whether they know the thermocompensation method used in the The Citizen's movement (the A660)? Yes, I know that some of the Seiko folks state it's dual crystal, but this just doesn't make sense to me for a number of reasons.
 
#28 ·
Thomas. Would it be possible to ask your Citizen friends whether they know the thermocompensation method used in the The Citizen's movement (the A660)? Yes, I know that some of the Seiko folks state it's dual crystal, but this just doesn't make sense to me for a number of reasons.
I did ask, and was told "it was a secret". But it was at a gathering of engineers from both groups ( retired ), and there was a great deal of joking back and forth about the reverse engineering of the Seiko I mentioned. Putting my cultural hat on, I think there is something there. What I wrote in another section about the Seiko +- 5 second watches being too sensitive and Ferraris and the 8j and 9F being more stable was agreed on by all. The Citizen was thought by all to be more fickle. Hence it being sold with an embedded service package. I'll keep pursuing it.

Best Thomas.
 
#34 ·
I agree with your questions, George, but would still include whether it has a second crystal as an additional question. This is a key part of the scheme. Of course, they may choose not to answer, which is why you didn't include the question.

Thomas -- If you were game, I wonder if we could put together a consensus list of questions that you could put to your acquaintances?

Another thought is that, if any speak (or read/write) english, I wonder if they would be open to an e-mail interview? (We would, of course, totally respect any boundaries that they place on proprietary information.)
 
#37 ·
Hi,

after reading all this, Im confused about my next purchase.

My birthday is coming up soon and I was thinking of rewarding myself with another Japanese HEQ.

After reading Petew's recent purchase of the Campanola with an A660, I was going to jump on it at the 1st impulse. I contacted Higuchi San , got the prices etc. Then I stopped and started thinking again.

My last purchase with an A660- a CTQ57-1022, was not up to specs. It was outside the 5 sec range. I have read reports of ALL GS owners reporting better specs than the 10 sec per year claim. SO I started veering towards the GS.

The readers of this esteemed forum, have uptil now held the 9F in very high esteem. SO I started looking for models with a 9F62.

Now, after reading the latest info, if the 8J IS really that good, then/ maybe I should lean towards the SBGF019. It has everything I require, timezone change function, 5 year battery life, screw down crown. AND IT IS CHEAPER TO BOOT.

Im using you guys as a sounding board. AM I wrong in thinking this way?

Please help

regards,
JRP
 
#38 ·
Hi,

after reading all this, Im confused about my next purchase.

My birthday is coming up soon and I was thinking of rewarding myself with another Japanese HEQ.

After reading Petew's recent purchase of the Campanola with an A660, I was going to jump on it at the 1st impulse. I contacted Higuchi San , got the prices etc. Then I stopped and started thinking again.

My last purchase with an A660- a CTQ57-1022, was not up to specs. It was outside the 5 sec range. I have read reports of ALL GS owners reporting better specs than the 10 sec per year claim. SO I started veering towards the GS.

The readers of this esteemed forum, have uptil now held the 9F in very high esteem. SO I started looking for models with a 9F62.

Now, after reading the latest info, if the 8J IS really that good, then/ maybe I should lean towards the SBGF019. It has everything I require, timezone change function, 5 year battery life, screw down crown. AND IT IS CHEAPER TO BOOT.

Im using you guys as a sounding board. AM I wrong in thinking this way?

Please help

regards,
JRP
Hate to spoil your happy thoughts about the Seiko GS, but mine was not within the advertised spec when I received it. It was running at +16 sec/yr.

Now the good news. The 9F movements are user adjustable and after adjustment the watch is running at a smooth +7 sec/yr.
 
#40 ·
@JRP : Well, what you describe is almost exactly what brought me to get a SBGF019. I've been hesitating for a while, since I wasn't sure its style was worth the price. Then I found this site, with pretty good pictures and a reliable vendor on eBay.
I must say this GS is way beyond my expectations : the overall quality of the making is stunning. Dial, lume, case, bracelet : everything is better than expected (you read posts about it but you're waiting anxiously to get your hands on it so that you can check ...)
It has all the features I wanted and it's about half the price of many other GS ... and it looks great. Cool. BTW, in 6 weeks it hasn't lost or gained any second [I wear it day and night 6 days a week].
 
#41 ·
Hi all, This thread has quite an impressive group of contributors.

My question is: Which movement do you consider to be the most accurate of all the HAQ. From the reading I have done just today, the Seiko 9983 (and a few others) has a method to account for and adjust for temperature variations. Many other movements with close or even better yearly specs are made to be less sensitive to temperature variations but are tuned to be worn a certain number of hours each day in order to fall within their published specs. Thermal control (Sort of)! Even the Very High Frequency movements, that hold the records for accuracy, are made to be less sensitive to temp but still require a wearing schedule to meet specs.

If not worn within any schedule and often left unworn for weeks, wouldn't the Seiko 9983 (and the other temperature correcting movements) have the highest accuracy? (Assuming they are still working properly)
 
#42 ·
Rather an old thread. A bit of searching a reading through more threads (especially more recent ones) could answer your questions.

Of currently available HAQs:
- ETA Precidrive and (most) Grand Seiko cal. 9F movements are spec'd to 10 SPY
- All of Citizen's top movements and some Grand Seiko cal. 9F are spec'd to 5 SPY
- Morgenwerk and some Hoptroff watches are spec'd to 1 SPY or better, but we have yet to see any user test results from these

All quartz watches, including HAQs, will perform better if kept in temperature-stable environments. Thermocompensation can go some way towards correcting for variations in temperature, but there is a reason why labs use ovenized crystal oscillators, rather than thermocompensation.

Seiko's 9983 was the cream of the early dual oscillator watches and I have heard that these can still be sent back to Japan for rate adjustment. Adjusting one yourself, after all these years, would be a nightmare due to the differences in ageing that each of the XOs will have experienced over the last 38 years.
 
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