Reply With QuoteIs this what you need? http://www.timefactors.com/smithsprs68.htm
Where can I find information about the PRS-68 diver?
Is this what you need? http://www.timefactors.com/smithsprs68.htm
I read that a couple of weeks back. What a magnificent review!!!Originally Posted by Seamaster73
Said it before and I'll say it again, one of the best things about a new watch from Eddie is getting a new review from Ewan.
This just completely changed my view on the Miyota 9015.
"One aspect of the calibre’s simplicity is the unidirectional winding of the rotor – in layman’s terms, the rotor winds the mainspring when it rotates in one direction; if it rotates in the other then it does not – it freewheels. I always had mixed feelings about this arrangement without really doing any research. Being so impressed with the PRS-68 in all other aspects thus far, I thought I would see if there might be any benefit (apart from mechanical simplicity) of the unidirectional winding system.
I am lazy, without doubt. Or perhaps to be fair, my lifestyle is relatively sedentary. If I am wearing an automatic watch the winding of such needs to be efficient; and to my delight, it appears that with a non complicated automatic movement (e.g. no chronograph) then unidirectional winding is the order of the day. It has been proven to be more efficient than bidirectional winding in many conditions – including those of slouches like me.
The technical aspects of this (which I shan’t explore in any depth) concern inertia and dead angles – basically, the less mechanical resistance that the winding mechanism has to overcome in order to wind the mainspring then the more quickly the mainspring will become wound. A bidirectional system uses a relatively high proportion of the angle of swing of the rotor when the rotor changes its direction of rotation just to get the reverser mechanism ‘sorted out’ before transmitting energy to the mainspring. This is particularly critical when small movements of the wrist translate into gentle back and forth rocking of the rotor. A good proportion of that gentle rocking is not actually doing anything apart from setting the reverser mechanism (whatever type it might be) ready for further rotation of the rotor which might not actually take place.
A unidirectional winding system on the other hand, has no reverser mechanism. Whilst the rotor is moving in the non winding direction it is doing nothing for the mainspring (and we can hear it freewheeling); but the vast majority of energy from the slightest movement in the winding direction is transmitted efficiently – the dead angle is less and the mainspring is wound more.
For those who are very active this is perhaps rather academic. I have always wanted to feel as confident in something that is purported to be doing ‘half a job’ as one which goes the whole way and Jaeger LeCoultre’s findings have allayed any fears I may have had; as reported in Watchtime Magazine:
“We tested Caliber 899 in two ways, in the standard version with bidirectional winding and in an altered form with unidirectional winding. Unidirectional winding was significantly slower on the Cyclotest machines. But we also asked different people to wear these watches on their wrists. We gave them wristwatches with slack mainsprings and asked them to wear them from 8 a.m. to 4 p.m. On average, watches with unidirectional winding were twice as strongly wound as watches with bidirectional winding.”
I decided to conduct my own experiment on the basis of the above. With the PRS-68 absolutely stopped, no power at all, I gently twisted it and tilted it back and forth for precisely three minutes. I didn’t put it on my wrist, just held it and moved it. It took almost all of those three minutes to get up and running but once the seconds hand was scurrying its way along, I set the watch back in the box and waited. From those three minutes of movement the watch ran for no less than 6hr 25min. Thus, it appeared that three minutes of movement gave me about one seventh of total power reserve! Very impressive. Next, I did exactly the same with a brand new Seiko 4R36 (bidirectional winding) equipped watch, moving the watch in very much the same way as the Smiths for the same amount of time – the Seiko ran for 3hr 55min. Whilst my little experiment wasn’t particularly scientific, it seemed to back up JLC’s findings and it has to be said, gives me great confidence in the Miyota 9015. It is more efficient than an equivalent mainstream Seiko movement – for me anyway. For those more active then the chances are that both systems are just about equal."
There's one up for sale.
https://www.mywatchmart.com/listing/...9cPmAXptI_rEGs
Eddie
Whole chunks of my life come under the heading "it seemed like a good idea at the time".
Unidirectional is actually better than bidirectional... because there are less parts to go wrong or wear out. Performance wise, it makes no difference.This just completely changed my view on the Miyota 9015.
One on eBay now. With three days still to go the bidding has reached £470.
Last edited by seabiscuit; 12th February 2019 at 08:24.
I know that now because I did read the part I quoted and posted. Although I doubt if "less parts to go wrong" comes into it.
The wobble is still annoying though and I would still choose a 6R15 over a 9015 every time. I probably won't hesitate to buy a 9015 powered watch now though.
I missed the one on mywatchmart, keeping a sharp eye on the one on Ebay.
A lot of good information since I'm not familiar with the 9015 movement.
Smiths on eBay has been sold......
Went for £575.
Finally found a PRS-68........its in the US finally and heading to Virginia soon!!!
The PRS-68 arrived today!! What an amazing watch!!
Come on then, pics,,
n2
"Once is happenstance. Twice is coincidence. The third time it's enemy action."
'Populism, the last refuge of a Tory scoundrel'.
Working on that...thought I knew how to post a pic!
Last edited by WatcherofTime; 1st March 2019 at 03:17.
Lovely watch. I should have kept my first one...
Cheers,
Adam.
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It took me about a week or so to read the review(work got in the way).....I didn't want to miss a word! After that I was hooked and I knew I had to get my hands on one.
Does anyone know how many were made and when the PRS-68 was discontinued??
Perhaps Eddie is already aware - but the current re-issue mania will likely fuel a strong demand for the PRS-68. Based on the reports from Baselworld 2019 a particular Japanese re-issue is being introduced for $4,250. At this price point most of us are interested in other options. A PRS-68 re-issue would do nicely
I totally agree with you. I was aware of the 6105 re-issue and the ridiculous price but I didn't want to interfere in the thread with it.
I'm gonna buy all of the PRS-68s I can find.
Wearing mine today
One on eBay now
https://www.ebay.co.uk/itm/Smiths-20...kAAOSw6DNcjOPX
Eddie
Whole chunks of my life come under the heading "it seemed like a good idea at the time".
Love that combo, I stupidly sold mine an bought a black turtle.Wearing mine today
...nearing $900 now!!
Hope you do another run of these watches. I missed out on the 1st run but am on the lookout for a good used one.
N
How true.
Brane
Why does the guy on Ebay keep re-listing it?
Yeah, I'd like to know that - because it seems to get bid on - and reaches a high price.
I wonder if he actually has it? 🤔
Can't figure it out. Bidding goes past the reserve and then its listed again with the same pictures. I'm just curious, not bidding on it.
The seller is bidding it up from another account.
"Once is happenstance. Twice is coincidence. The third time it's enemy action."
'Populism, the last refuge of a Tory scoundrel'.
Easy thing to do especially with a £1 listing promo. He probably had the wife and kids bidding on it and his max loss each time is £1. Only takes one serious bidder to jump in at the end and he has achieved his objective. Not condoning it, but it's easy to see how it's done.
Smiths PRS-68
There is a Smiths PRS-68 on the SCWF now.....
Just arrived and although minus the steel bracelet was a steal. £250
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Well done! Where did you get it from?
Just arrived and although minus the steel bracelet was a steal. £250
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Congratulations! I've loved mine since I got it, I think it's been one of my most worn watches over the last couple of years. I've become a strong convert to the joy of Perlon straps, and i think they suit the PRS-68 very well indeed. (The bracelet is also good, so unfortunate yours is missing that.)
Dave E
Skating away on the thin ice of a new day
Ebay chaps... I leapt on it!! I’ve got a steel bracelet as below which is cool but not the one that comes with it.. still really pleased with it. Number 55
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