Jump to content

Recommended Posts

Good evening guys,

I'm sorry for the delay in my reply. It was almost midnight when I tested the Timetrax sensor and I got excited because it worked well so I wanted to post it albeit without details.

@guidovelasquez I will attempt to record a sound sample, but perhaps what would work better is to take a screenshot of the waveform from WOS? I'll try soon.

I came across the ad that @JohnR725 posted above and took quite a bit of interest. The most practical way is to access their eBay store. The link to the Timetrax sensor is here:

http://www.ebay.com/itm/Watch-Pick-Up-Sensor-w-VISE-for-Beat-Amplifier-Timing-Machine-Diagnostic-Tool-/231770041124?hash=item35f6922b24:g:4pAAAOSw7FRWXNv7

They also offer the alligator clip as well as a mini-speaker. I only ordered the sensor which plugs right into my amplifier that you see in the picture. The amp then connects to my PC.

 

I have PEACE running alongside WOS. What is interesting, is that I played around with the EQ and found out that what actually works best is to MINIMIZE the NOISE, rather than amplify the waveform. Turns out that the frequencies I had boosted to get a nice triple wave produced the best results if I actually lowered them. The waveform is not particularly tall but the noise is really low allowing WOS to capture the graph in the picture above.

I compared the waveform between the Timetrax sensor and my Korg mic and the TT works much better. In addition it is made out of metal and it allows to position the watch in multiple positions without the risk of it falling or slipping.

I'm very satisfied to have a quick timegrapher to adjust then the WOS to test over longer periods of time.

I'll try to capture the waveforms soon.

Cheers!

 

Share this post


Link to post
Share on other sites

Bravo!!!!:Bravo: :thumbsu:

Are good news. Thanks for the information you share. It is correct what you say about equalization it is better to lower almost all frequencies. But without lowering the frequencies where the most important sound of the exhaust mechanism is present. We are eager to see the waveform. I have a question: do you have any filter applied to the WOS configuration? It would be nice to see the waveform without any filter application. This allows us to see how much noise the TIMETRAX microphone picks up.

Share this post


Link to post
Share on other sites

For a picture of what's inside the TIMETRAX microphone can be found on page 6 of this discussion found at the link below, at least a picture of the older style I imagine the constructions the same it's just a different housing now. The cost fortunately is still the same to hard to justify making one. Then I don't think I ever got around to posting the inside of the watch pickup which if anyone is interested I could do it's actually quite simple inside.

http://www.watchrepairtalk.com/topic/3002-d-i-y-watch-timing-machine/?page=6

Share this post


Link to post
Share on other sites

I have a suggestion, tell me if this is crazy? If I were to have a primary contact piezo microphone touching the watch under test as always and if I also plugged a second microphone into my PC that was basically just hanging off the PC not involved with the test. Could you take the input from the second microphone and subtract it from he first? My thought is that you could do active noise cancelling that way it and it would remove all of the environmental noise, leaving just signal. I looked and a second USB dongle microphone/speaker "sound card" costs like $7.00 now. If this worked, it would be a really solid feature.

Share this post


Link to post
Share on other sites

That's not such a crazy idea, although it would be best if the second microphone were also in the watch stand, but isolated from the watch. That way, any noise picked up by vibration of the stand itself would also be cancelled. If you have a regular sound card with a stereo line-in, you wouldn't even need a second card, just some software changes.

In fact, you may not need a second input at all. Simply wiring the two piezos in series, with one pointing in the opposite direction, should have the same effect. In fact, that's exactly how the microphone in the headset I'm wearing in my avatar works. One mic faces my mouth, and the other faces away, and only the difference is picked up by the plane's audio panel.

Share this post


Link to post
Share on other sites
Bravo!!!!Bravo1.gif thumbsu.gif

Are good news. Thanks for the information you share. It is correct what you say about equalization it is better to lower almost all frequencies. But without lowering the frequencies where the most important sound of the exhaust mechanism is present. We are eager to see the waveform. I have a question: do you have any filter applied to the WOS configuration? It would be nice to see the waveform without any filter application. This allows us to see how much noise the TIMETRAX microphone picks up.

 

 

Here's the EQ on PEACE

 

51dfdf01a1f1178566c0c02bf0fe8735.jpg

 

 

 

Here's the waveform:

 

f0927bc7786eec7c79ef993a24212f7a.jpg

 

 

Here's the resulting trace:

 

ad3bef663a01ec9ab169162bb6a77794.jpg

 

 

 

 

 

EDIT: and I have to add that my setup is anything except sofistic**BLEEP**. The mic and the amp have long cables I have curled up on twisties. I know that's a source of noice.

 

Sent from my iPhone using Tapatalk

Share this post


Link to post
Share on other sites

Thank you very much for the information you share. I can rate the signal coming to your computer as excellent. The noise that is created I think can be eliminated if you do the same in the equalizer with the controls that you have lowered. Lowering them all to the left the very low frequencies. There is no useful information for the program Particularly do it with the network. If in your country the network is 50 hz. Give special attention to that band. Even at least in my country sometimes the network is not accurate 60 Hz. Is 59 0 61. You can in the "Peace", change the value of the band by an exact one to remove all the hum of the network.

:bow::thumbsu:

Share this post


Link to post
Share on other sites

The determination of "weight" is, in a sense, subjective. There are very predictable positions in the watch's posture. One of them is "Dial up". We assume that 8 hours rest and the clock as norm is in that position. That position will have more weight. There are less likely positions: Dial Down. Although not common, if possible. For example when our palm is up. That position has a smaller "weight." The "crown up" position is unlikely too, and it is presented when we raise the hand to the height of the face and the elbow in its lowest position. And so on. Although we can make an average we give priority to certain positions. The watchmaker should know to some degree the habits of his client. Or if we do it without being watchmakers, we know our habits. This is my opinion, and I would appreciate if anyone can add something to this.

Share this post


Link to post
Share on other sites
22 minutes ago, garrettwp said:

Will something like this work for a mic preamp? It offers a 50dB balanced / 44dB unbalanced gain.

https://www.bhphotovideo.com/c/product/155445-REG/Rolls_MP13_MP13_Mini_Microphone_Preamp.html

 

- Garrett

I can't say 100% for sure, but it looks like it might. You will need a 1/4" to 1/8" cable to connect that to your PC's audio input.

Share this post


Link to post
Share on other sites
1 hour ago, svorkoetter said:

I can't say 100% for sure, but it looks like it might. You will need a 1/4" to 1/8" cable to connect that to your PC's audio input.

 

Thanks for the replay. I see Amazon has it as well and most of the review are okay with some reporting it being noisy at high gain. Another issue I see reported is of quality issues. I may order from Amazon and if it does not work, just return it. I would build one of the preamps posted on here, but my time is a little limited. I also seen one of these:

https://www.amazon.com/Universal-Mono-Pre-Amplifier-Kit-Intermediate/dp/B0002Z82XU

- Garrett

Share this post


Link to post
Share on other sites
7 minutes ago, svorkoetter said:

That one might also work.

Do you think it would be best to order the kit from Amazon and give it a shot? Or would the Rolls preamp be my best bet?

- Garrett

Share this post


Link to post
Share on other sites
29 minutes ago, garrettwp said:

Do you think it would be best to order the kit from Amazon and give it a shot? Or would the Rolls preamp be my best bet?

- Garrett

It depends on if you want to take the time to build it, wire in the cables, etc., or just want something that might be plug-and-play (note that for both options, you'll still need a power source).

Share this post


Link to post
Share on other sites

I just ordered the Rolls Preamp, I will report back on how it works. I will be using a Microset Watch Timer clamp sensor that I ordered with my Microset Watch Timer back in 2008. It is a standard piezo sensor mounted on a watch case holder. When I realized what was inside the under, I could not believe that they charge $195 US for the thing!

- Garrett

Share this post


Link to post
Share on other sites

On my computer, full scale on the WOS scope mode corresponds to 100 mV at the Line In input.  My preamplifier is like the WOS design but modified for lower noise (still same 75 dB gain and passband). My microphone is like the WOS design but has an 18 nF capacitance.

I find that, with the voltage divider at the output of the preamp set to 0.010 of maximum, the WOS software still produces a usable result. The power gain for this situation is only 35 dB. I think, therefore, that many audio preamps will have sufficient gain to work with the WOS software.

At 35 dB preamp gain, the trace on the WOS scope mode is very small, barely visible, but the watch-timing feature still works.
 

Share this post


Link to post
Share on other sites

So I received the Rolls preamp and if it were not for the buzzing sound coming from the output, it would have probably worked well with the software. Unfortunately the preamp exhibits a loud buzzing sound when turning up the gain.

 

- Garrett

Share this post


Link to post
Share on other sites

Is this pre-amp battery-powered or is it powered from a wall wort?  if the latter, then possibly you have grounding problems.  One test would be to power it through an isolation transformer that disconnects the device ground from the mains ground.  Can you convert it to battery power?

Share this post


Link to post
Share on other sites

The problem is with the cable shielding. They catch buzzing from the home mains.
I have experienced it. Excellent cable shielding is required. Also the microphone itself, especially if it is a piezo electric ceramic. This serves as a "radar" for the hum of the network. Do this test to determine if the preamplifier is not of good quality. Connect it to your computer but DO NOT CONNECT ANYTHING TO THE PREAMPLIFIER. LISTEN TO GOOD HEADPHONES. IF BUZZ, filtering DEVICE preamplifier is not good.post-670-0-99643800-1448514753_thumb.png

The appearance should be similar to this. Little noise and a pretty clear signal.

Share this post


Link to post
Share on other sites
9 hours ago, guidovelasquez said:

The problem is with the cable shielding. They catch buzzing from the home mains.
I have experienced it. Excellent cable shielding is required. Also the microphone itself, especially if it is a piezo electric ceramic. This serves as a "radar" for the hum of the network. Do this test to determine if the preamplifier is not of good quality. Connect it to your computer but DO NOT CONNECT ANYTHING TO THE PREAMPLIFIER. LISTEN TO GOOD HEADPHONES. IF BUZZ, filtering DEVICE preamplifier is not good.post-670-0-99643800-1448514753_thumb.png

The appearance should be similar to this. Little noise and a pretty clear signal.

 

When nothing is hooked up to the preamp and the preamp is only connected to the computer it is silent. As soon as I hook up the piezo microphone, I get buzzing.

 

13 hours ago, robmack said:

Is this pre-amp battery-powered or is it powered from a wall wort?  if the latter, then possibly you have grounding problems.  One test would be to power it through an isolation transformer that disconnects the device ground from the mains ground.  Can you convert it to battery power?

 

The unit is AC powered by a wallwort. It can take a voltage of 9-15V. The wallwort is rated at 15V 500mA.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...