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The Well Tempered Master Clock - Building a low phase noise/jitter crystal oscillator
The Well Tempered Master Clock - Building a low phase noise/jitter crystal oscillator
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Old Today, 01:46 AM   #1851
karahana is offline karahana
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Join Date: Apr 2013
When is the next GB?
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Old Today, 07:27 AM   #1852
gentlevoice is offline gentlevoice  Denmark
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The Well Tempered Master Clock - Building a low phase noise/jitter crystal oscillator
@wlowes: Thanks for sharing your design choices and their impact on the sound. Very interesting, indeed ... Not least that "stability" - be it in terms of thermal or vibrational - appears to have great effect on the sound.

Cheers,

Jesper
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Old Today, 08:36 AM   #1853
andrea_mori is offline andrea_mori  Italy
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Quote:
Originally Posted by wlowes View Post
I currently use the WTMC with a 12-inch SMA cable rated to 16gHz. I did an experiment to determine impact of cable. After getting to know the WTMC on the 12 RF cable, I removed the cable and attached the clock directly to the FIFOPi. I believe there was an improvement in sound without the cable. I heard more dynamics and attack without the cable. While I attempted to keep all other variables the same, the direct attach also had the oscillator pinned against the granite slab. So it is possible that part of the improvement was due to attenuated vibration.

The next time I moved the WTMC onto a cable was when I installed it into its new chassis with an improved power supply. In some ways the sound improved, but also the improved dynamics seemed to disappear in the chassis.

But then I added the sand into the chassis, and the sound was elevated to a level beyond any other configuration.

My conclusion is a 12 cable degraded the signal in some small measure, but that impact was more than offset with the isolation of the chassis.

Clearly anyone could be very happy with the sound from the WTMC directly attached to the FIFO or cable attached from its own chassis.

IMHO the best sound comes with a separate vibration dampened chassis using a modest length of SMA cable.

In the future I will swap the 12 cable with a 6 between the clock chassis and the FIFO. This will be a good test of only the cable length.

Again, thanks to Andrea and all the contributors on this thread. You have elevated my system to a different level.
Hi Walter,

very very nice job!
And great explanation with plenty of details!

Many thanks for sharing your experience.

Andrea
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Old Today, 08:38 AM   #1854
andrea_mori is offline andrea_mori  Italy
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Originally Posted by karahana View Post
When is the next GB?
As soon as the new Driscoll board will be ready and tested, I think within a couple of months.

Stay tuned!
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Old Today, 06:43 PM   #1855
clsidxxl is offline clsidxxl  France
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When the new Driscoll board will be ready,it could be interesting to add a R.F enclosure at the height,I thought of something of this quality https://www.gquipment.com/33-thickbox_default/rf-enclosure-mini-aluminium.jpg
a design and a buying group would be possible,there are a lot of options,for example Machined Enclosures or even Custom Rf Cnc Machined Parts Aluminum Enclosure Housing Shell - Buy Aluminum Rf Enclosure,Rf Enclosure,Custom Rf Enclosure Product on Alibaba.com
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Old Today, 08:26 PM   #1856
Supersurfer is offline Supersurfer  Netherlands
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Quote:
Originally Posted by andrea_mori View Post
As soon as the new Driscoll board will be ready and tested, I think within a couple of months.

Stay tuned!
Hi Andrea,

I hope you will find a more easy solution for the oven of the bigger crystal enclosures than the copper pipe. Forming the pipe to the exact dimensions to fit the crystal is a difficult task and has taken me more time than soldering the driscoll and oven board.

Regards,
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Old Today, 08:27 PM   #1857
Supersurfer is offline Supersurfer  Netherlands
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Hi Wlowes,

Thank you for your elaborate explanation, it is very informative!
Have fun with your new clock!
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Old Today, 08:42 PM   #1858
Supersurfer is offline Supersurfer  Netherlands
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Quote:
Originally Posted by andrea_mori View Post
Supposing the 7812 of the oven to be oscillating you could try to replace input and output capacitors C1 and C2 as Jesper suggested.
You could try 100uF/25V as the input capacitor C1 and 22/47uF/25V as the output capacitor C2, both standard electrolytic capacitor (high ESR) not organic polymer and so on.
Pay attention to the polarity of the above capacitors.

Then, if the issue has not solved you could replace the servo capacitor C3 with a 1uF/50V film capacitor.
Hi Andrea,

I have moved the clock unit to another dac to test the rfi influence. It is a dddac feeded by rpi streamer with fifopi.
The noise has dissapeared but when I power on the oven after about a minute the music stops; the fifopi switches to the second clock. This happens with and without a second clock mounted.
Frequency lock is lost.

I must mention that I am still not able to do an accurate temperature measurement, I have ordered a good temp. measurement device; this will be shipped next week.

So it seems that there is another problem than rfi interference.
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Last edited by Supersurfer; Today at 08:48 PM.
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Old Today, 08:52 PM   #1859
wealas is offline wealas
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If I remember correctly, a small plastic tray was needed between the crystal and the board, did you put that in?
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Old Today, 09:45 PM   #1860
wlowes is offline wlowes  Canada
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Quote:
Originally Posted by Supersurfer View Post
Hi Andrea,

I have moved the clock unit to another dac to test the rfi influence. It is a dddac feeded by rpi streamer with fifopi.
The noise has dissapeared but when I power on the oven after about a minute the music stops; the fifopi switches to the second clock. This happens with and without a second clock mounted.
Frequency lock is lost.

I must mention that I am still not able to do an accurate temperature measurement, I have ordered a good temp. measurement device; this will be shipped next week.

So it seems that there is another problem than rfi interference.
Hi Supersurfer
Sorry you are having oven issues.
If I understand correctly, the clock works as expected without the oven, but after about a minute of switching on the oven you now loose a clock signal. On ESS Dac it developed noise one minute after oven was powered??

I am shooting in the dark, but perhaps one more test would be to remove the oven. Then fire up the system and confirm it is fully operational. Then apply heat from a different source like an air station, blow dryer or heat gun. Attempt to get the temperature in the same range as the oven and see if it works or exhibits the same failure mode. It might narrow it down to a thermal issue in the clock pcb vs an electrical issue related to the oven/clock.
It's a head scratcher
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