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Could be ground looping. I had the same problem when using a laptop through a PA system. Removing the ground solved the problem.

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Could be ground looping. I had the same problem when using a laptop through a PA system. Removing the ground solved the problem.

 

In the case of my UK watchmaker friend, he had the problem even when the laptop was running on batteries, so there was no further ground to remove.

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Hello!

 

Last night I tried again, with the laptop on batteries,  and I managed to get some information (on my Molnija 3602 pocket watch that doesn't let you sleep - it is  that loud): 200ms dead for the semi-period (at 18000bph) with 13ms lift time (for a 42° lift angle) which would mean an amplitude of about 206° - not bad for a 20 year unserviced movement.

 

That is quite a victory for me!

 

Thank you Stefan!!!

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I did that in an aircraft once. :(

 

That does not sound healthy Geo!

 

 

 

 

As a slightly different perspective I thought I would take some pictures of the microphone I use with the Escapement Analyzer software. This just works by plugging into the sound card on my laptop or PC. The microphone was from my old Greiner timing machine. I threw the machine away and kept the microphone to use with the software. I get an excellent amount of gain with very little noise. The microphone will pick up noises from across the room as well so I am often reducing the volume to about 1/3rd gain.

 

Here are some pictures, I hope it helps someone. And svorkoetter, if you want me to test this with your software then fire me off a demo and I will be willing to do that.

 

The microphone with the old socket removed and a stereo mini jack soldered in place:

 

post-1-0-38533200-1424350314_thumb.jpg

 

Pictures of how the jack is hooked up:

 

post-1-0-33717800-1424350313_thumb.jpg

post-1-0-86467800-1424350313_thumb.jpg

 

Inside the microphone chassis:

 

post-1-0-94355700-1424350310_thumb.jpg

post-1-0-56919900-1424350311_thumb.jpg

 

The coupling which allows this particular microphone to turn 360ºs - excellent for poising work.

 

post-1-0-43606000-1424350312_thumb.jpg

post-1-0-92433900-1424350312_thumb.jpg

 

No pre-amp is needed, this works by just plugging into the computer sound card.

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Interesting microphone!

 

I'm going to start rethinking my microphones. At the moment, they are based on piezo elements, which require about 5000x amplification to produce a signal that the sound card can handle. As I've discovered, under certain conditions, this can also amplify unwanted AC hum. I may experiment with using an electret element, coupled to the watch by an aluminum plate.

 

I'm also working on the software a bit right now, and will try to get you a copy in the next few days Mark.

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If you dissect the microphone that came with the Escapement Analyzer software you'll find it has the same green sensor as found in the modified Greiner timing machine pick up. Then in the pickup there is a little bit of circuitry two transistors and three surface mount components soldered together. For the Greiner Pickup we can't see were all the wires go it's possible the circuitry is in there somewhere. So I've attached a photograph of what the microphone looks like dissected.

 

Then as the green thing is rather unique in color and shape I suspect it's probably this one

 

http://uk.rs-online.com/web/p/vibration-sensors/0285784/

http://docs-europe.electrocomponents.com/webdocs/009f/0900766b8009f3f3.pdf
 

 

post-673-0-62748900-1424504676.jpg

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Hello!

So I had some sort of revelation, please don't laugh if it's so obvious: the timegrapher (actually the sensor) works better if you hold the piezo senzor pressed against the movement/watch case - I used a sort of plastic clippers. It will pick-up less noise from the environment.

I thought that that microphone stand was only useful to hold the movement in different positions, but it actually presses against the watch with the clamp that has the piezo element stuck to it.

Also, as a friend of mine pointed out to me, the stand has to be heavy, so it will pick up less noise from the environment.

And also, having a very low amplitude helps seeing the three distinct sounds inside a tic ;)

 

Bogdan

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Yes, you'll notice that in my home-made microphone stand earlier in this thread, the crown of the watch is pressed right against the microphone element. I'll go so far to say that the word "better" isn't needed in your sentence, as it doesn't work at all if the watch is not contacting the element.

 

Your comment got me thinking however, that perhaps part of the reason my microphone picks up more ambient noise than I would like is that the sensor element is quite large (27mm diameter), which is not really necessary to contact a 5-8mm watch crown.

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At first I was just putting the watch over the sensor. Before touching the sensor there was a lot of ambient noise. As soon as I was letting down the heavy Molnija 3602 on the sensor, the ambient noise diminuated greatly. So the next step was to catch both the watch and the sensor in a set of calippers. Then only the Hiss noise remained. So the next step is to try your new preamp design to see if the noise can be reduced even more.

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For timing machines we have an interesting problem we want to listen to the sound of the watch ticking except in real life we want to pick up the vibration of the watch ticking. Clock repair has a similar problem they need to listen to the clocks they usually have an amplifying device with loudspeaker and they definitely do not want the pickup to receive the audio from the speaker otherwise you get incredibly loud rather irritating feedback. So vibration pickup with minimal or no sound is the best.

 

So clock repair finding a device to amplify with speaker relatively easy but finding a decent pickup used to be a problem. Some of the clock repair catalogs do sell them occasionally sometimes by themselves or bundled with the amplifier. But today places like eBay currently have two of them with the titles of “CLOCK Pick Up Sensor for Beat Amplifier” or “CLOCK BEAT SETTING PICK UP SENSOR”. If you read the description one of them comes from a company called Adams Brown. So a very long time ago they sold watch and clock repair books then they made a timing machine which goes by the name of Timetrax with a variety of models and a rather nice clip on pickup that you could buy all by itself.

 

So the outstanding feature is it’s very sensitive and very insensitive to audio sound. So dissected and photographed we see it is a standard electronic test clip soldered into a square brass tubing. Then a piezo buzzer attached a piece of brass which sometimes can be found referred to as a contact microphone rather than a buzzer. So the brass disk has been trimmed carefully so as not to break the ceramic material and soldered in place on the square brass tubing. Then a brass round tube fits over the whole assembly held in place with hot glue and a protective piece of heat shrink tubing hides the whole thing.

 

So alternative pickups one of my friends conveniently misplaced his TimeTrax pickup and a Clip-on Piezo Guitar Pickup found on eBay with the plug change to fit the timing machine is used as a replacement. For timing watches the guitar pickup is nice in that it is rubber padded and doesn’t scratch things like the TimeTrax one can. On the other hand it is slightly more sensitive to audio noise. Which isn’t a problem normally for timing machine because normally the timing machine isn’t outputting the sound.

 

So the blue pickup is what I consider a classic at least it’s timing machine that it goes with is a classic the Portescape B200. So the pickup as you can see can be rotated in a whole bunch of positions for multiposition timing which is really nice for troubleshooting. Then this pickup is very similar to the Greiner at least before it was converted. So basically the B200 timing machine is a very very popular timing machine found worldwide for a very long time until replaced by the modern electronic machines.

 

So now we get the confusing part. Watches held in the holder it’s a spring-loaded holder to make contact on the pins which transmit the vibration to the square crystal on the other side. The two large black headed screws hold the plate in place except which is not visible it’s held in place with rubber mounting. You can actually move the pins on the watch side and the plate does move a little bit. Then confusing wires because there are coils on the other side not visible for picking up balance wheel electric watches.

post-673-0-50454500-1424947875.jpg

post-673-0-88569800-1424947875.jpg

post-673-0-37958800-1424947876.jpg

post-673-0-89373100-1424947876_thumb.jpg

post-673-0-47436800-1424947877_thumb.jpg

post-673-0-04551800-1424947878_thumb.jpg

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Hi everybody.

I am really enjoy every post for this topic. Principally the last ones that envolve part of my job, as I had refurbished about four B200 machines and a Greiner MM1. My question goes to Mark about the Greiner mic that the photos he post at February 19. Was this mic already repaired or it is original as it came from factory? I know this mic and it is very old and at that time they don't use the piezo unit as the thiny green one. They use the same big square piezo pack as B200. I have an early mic from Greiner (model M71) and it use the same piezo pack as B200.

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Hi everybody.

I am really enjoy every post for this topic. Principally the last ones that envolve part of my job, as I had refurbished about four B200 machines and a Greiner MM1. My question goes to Mark about the Greiner mic that the photos he post at February 19. Was this mic already repaired or it is original as it came from factory? I know this mic and it is very old and at that time they don't use the piezo unit as the thiny green one. They use the same big square piezo pack as B200. I have an early mic from Greiner (model M71) and it use the same piezo pack as B200.

 

I think I can answer the question regarding the Greiner Microphone with a photograph. Here's a photograph of a unmodified original factory pickup.

post-673-0-26259100-1425011303_thumb.jpg

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Hi everybody.

I am really enjoy every post for this topic. Principally the last ones that envolve part of my job, as I had refurbished about four B200 machines and a Greiner MM1. My question goes to Mark about the Greiner mic that the photos he post at February 19. Was this mic already repaired or it is original as it came from factory? I know this mic and it is very old and at that time they don't use the piezo unit as the thiny green one. They use the same big square piezo pack as B200. I have an early mic from Greiner (model M71) and it use the same piezo pack as B200.

I payed Graham to refurbish the mic. I am sure he removed the old bits and replaced them. He put new rubbers and cable as well all for the price quoted on his website.

What's the black box to the right of the pickup for? It's and internal amplifier?

Not an amplifier. It just houses the sliding mechanism for the clamp.

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Thanks Mark and John. That was I thought.

Just one more comment about. The secret of these mics is not in the gain but in the band pass frequency that the piezo unit respond. How small size is the unit, the higher frequency it respond.

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  • 3 weeks later...

 

A friend of mine helped me with the board and I attached all the bits and pieces.

I can say that there is a noise improvement but not a great one.

 

I think the design of the movement/sensor holder is the key.

 

 

Thank you, Stefan!

 

p.s. I put the copyright on the board as a big "Thank you"!

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Wow, nice job on the board! It looks better than my originals! And thanks for putting my name on it.

 

I notice that you're using long, unshielded wires to both the piezo and the sound card connection. That simply won't work. You MUST use shielded cable for this (or better yet, for the jacks, buy ones that fit right on the board). That would explain most of any 50Hz or 100Hz noise that you're seeing.

 

EDIT: I see that you are using shielded cable to the sound card jack. But you need to use it to the microphone too.

Edited by svorkoetter
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Some samples: 
 
;;;
;;;

 

They are Citizen with 8200A 21600bph, Intra-matic 2892-2 28800bph, Dugena with Osco 100 18000bph, russian Monija with a 3602 18000bph.
Amp1 and Amp 2 for the first and the second design.
Notes: for the first amp I was only putting the watch on the piezo transducer. For the second Amp, I put the both the watch and the sensor in a case-opening holder for better contact and less ambient noise (for the first amp you may hear a clock I have on the wall). All the recordings were made by inputting the signal on the mic-in on an HP Probook with low quality audio hardware. I wasn't able to select line-in instead of mic-in so there is an amplification carried by the audio board also and hence an additional noise. The noise is considerable lower when listening directly on a set of in-ears head-phones.
 
Question: Is there any obvious way to reduce that hiss annoying noise from the recordings?
 
I hope my feed-back helps,
Thank you,
Bogdan
Edited by matabog
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They work on my computer - it just asks me where to save the file. Try another browser.

Anyway, is there anyother place where I could upload the files? I am really interested in your opinion about that noise.

 

Thank you,

Bogdan

Edited by matabog
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