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About Ajohnw

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  1. I got off to a bad start on this thread. Title should be chronometers - automatics. Maybe a mod can edit it for me. My brain was elsewhere when I posted. It came back as soon as I looked at the thread again. John -
  2. There are plenty of old watches about ranging from say 10 to 30 years old that don't keep good time any more.One for instance that I have at the longer end looses 30sec a day. Another more recent probably 15+years old 15 secs a day. I wonder how much of this is likely to be down to lack of servicing and or general wear and if that which parts are most likely to need replacing. Makes me wonder why people buy them other than this may be better than some new automatics. John -
  3. I don't appear to be having any problems down to no amp actually in the pickup. The fact that the preamp I'm using has a 100k input impedance might be helping with that. The main problem with amplification appears to be bandwidth - too much of it for 44khz sampling. Especially on older watches it appears to cause the peaks on the trace to move around / wrong one sensed by the software. I'd guess the bandwidth needs to be severely cut to stop that completely but a10khz or so limit on that might help a lot. There seems to be a similar problem on the mic end. Old watch, move things around but watch still face up and the traces become stable. stick a new one on where it doesn't usually matter and suddenly it isn't stable. This is with the watch and mic resting on 25mm of soft foam. The as it turned out to be crap built in on board sound on my HP Mini tiny pc thingy could be helping as it's bass response is appalling. It's for a head set where this doesn't matter. I recently fitted a Soundblaster X-Fi HD usb card and now like the speakers I am using. It should give a better noise floor than the on board but unfortunately the mic input is for dynamic mic's so don't have enough gain. Problem with buying the china watch mic is price - not that much less than the whole kit. I just don't like that sort of thing. I've found a better than average case holder and am wondering if I can build a spring loaded pickup into it. I'm not well placed for that sort of task at the moment. It's this holder. It could even cope with a pocket watch. https://www.amazon.co.uk/gp/product/B07TZMH57B/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1 Most of the ones amazon sell struggle to hold a 40mm watch. The one I bought and reviewed is all plastic but really solid. At some point I can make some metal pegs and use it as a movement holder as well. It would be a pity if they have switched to metal. Plastic wont transmit sound so well. Johm -
  4. I've wondered about regulating a watch myself and came across this. There are other pages about as well. https://tg.ciovil.li/ Mixed success The volume control is a linux utility and shows signal strength after the preamp. It was fed into a laptop headset socket via a splitter lead. This is a stable trace off a new Seiko. A 15 year old chronometer usually doesn't give such a stable trace, it's running 15secs a day slow. It still seems to get the timing error correct despite this and playing around with position may give a more stable trace. Any new watch so far does give a stable trace. General bits bought off amazon UK. The pickup is intended for a violin. Seems to be 2 problems. Bandwidth of the electronics, too high with an amp like this and probably similar, the mechanical aspects of the pickup. Unfortunately commercial microphones for this use are rather expensive. If anyone else tries to install on Linux I found that the automated build wouldn't work but the usual ./config etc did and indicated what lib files I needed to install. John -
  5. I was just curious about faults so googled the movement and found this https://wahawatches.com/restoration-zentra-watch-with-fhf70-movement/ 15 jewels though John -
  6. I'm not sure how I joined this forum. Clicked on a links starting on youtube. Anyway I seem to be here and also on watchcentral where I thought a moderator would never read my first post. I've wrecked one or two clocks over the years and also had some success so for some reason I am not entirely sure of thought why not try watches. I do have a couple that look to be in need of some work and found the watch repair channel on youtube extremely useful already. John -
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