Reality is Cruel : Cybershaft new Ultimate OCXO 10M Clocks Shootout OP20 vs OP17

CKCK

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Aug 7, 2023
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stevebythebay

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Jpspock

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Thanks Steve, I found this information. But I was talking about, characteristics and quality.
 

Jpspock

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I bought their new bnc cable, and it’s a very good one. More precision, air a little faster.
Now they sell a new power supply… can be interesting…
 
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Jpspock

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This topic has never have a better name and description. I returned back my psu cybershaft of my op 21 for upgrade. I didn’t think this master clock had a so great impact in my system. It’s like I am looking without my glasses…
Really, cybershaft produce exceptional clock.
 

Jpspock

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Little question to our clock specialist. I thought that lowest noise reduction was -121db as for cybershaft op21. Now I read that msb has dac with -165db.
can anybody explain how it is possible ?
thanks for your explanation.
 

SCAudiophile

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@Jpspock Please copy-paste what you are referring to here (the text with that measurement and others). When talking about master and word clock specs, there are 3 main measurement points for phase noise quoted plus many other considerations to assess overall performance. The measurements are taken at 1Hz, 10Hz and 100Hz (and sometimes 1000MHz is quoted) with the units being "dbc/Hz", not "db". Phase noise (?(f)) is typically expressed in units of dBc/Hz, and it represents the noise power relative to the carrier contained in a 1 Hz bandwidth centered at certain offsets from the carrier....

For Cybershaft as an example (taken from their website):

"It is not possible to evaluate the product by measuring only the output characteristics of the built-in OCXO unit. Our calibration measurements do not directly measure the output of the OCXO unit, but rather from the output terminal of the product in order to evaluate all performance including the buffer circuit (so measurement of the actual overall component, not just an OCXO assembly):
<Grade selection value> PN = Phase noise ADEV = Allan variance
product gradePN offset 1HzPN offset 10HzADEV TAU=1sec
OP21A-D< -121dBc/Hz< -140dBc/Hz< 1.6E-13 (0.00016ppb/s)

*We have changed the previously published reference values for each grade to the screening values we actually use. All products already sold are shipped with the OP selection values in this table.
-The specifications of OP21E/-D are positioned as intermediate characteristics between OP21A and OP20A.
?As shown in [1] and [2], either PN or ADEV satisfies the specifications of OP21A.
?The overall characteristics are almost the same as [1] and [2]. [1] or [2] cannot be specified.

The above values are not general catalog values (typical) but guaranteed values measured individually, so the quality of the product is constant. There are no so-called "mistakes".
*For the value of phase noise offset 1Hz, an appropriate value from offset 1.000Hz to 1.099Hz is adopted to avoid averaging errors. Phase noise measurement is extremely sensitive and subject to measurement equipment and measurement errors. The phase noise values shown are not absolute values and include measurement errors. The phase noise values listed are values measured under the same conditions at our company, and are indicators of product grading.
The short-term stability value of Allan dispersion is not clearly defined by international standards, so there may be large errors between calibration laboratories. The above selection values are the values determined by our calibration equipment."

For the above, the numbers given are "standard values" (rounded) which are target certification values published for oscillators or this type. The test report on my 2017 OP21A OCXO Type2 model gives these exact numbers in the unit certification report (one compiled for each unit at time of final test before shipping):

< -122.1 dBc/Hz @ 1Hz offset actual (standard value is < -121 dBc/Hz)
< -142.1 dBc/Hz @ 10Hz offset actual (standard value is < -140 dBc/Hz)
< -147.4 dBc/Hz @ 100 Hz offset actual (no standard value noted)

Frequency value/stability must also be measured against a standard value of 9.999,999,995,00 MHz ? 10.000,000,005,00 MHz
with these devices over a prolonged period; to certify, there are several reference devices compared against including a Cesium frequency standard ("the standard" in the scientific world for clock accuracy and long-term stability).

Allan Deviation must also be taken into account and has standard values behavior at 0.1s, 1s, 10s intervals. Output level (from the BNC or other outputs) and Harmonic Distortion must also be measured and evaluated.

Allan Deviation, Phase Noise at the main measurement points and many others are used to calculate the overall performance of the master clock.

Looking at one number, no matter how impressive or a gap between numbers regardless of what it is does not allow the one device to be claimed as being superior (or not) to another.

I've included a Cybershaft mention and example text as I own their clocks over many years....this is not meant to spark any debates, only to help answer your question. Footnote: I have also owned Esoteric G-0s, followed by G-0Rb, then G-03X over many earlier years.

It would help quite a bit to see the rest of the text you are referencing and determine the overall context.
 
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Jpspock

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Dec 26, 2018
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As usual , complete information Thank you.
In fact I had a misunderstanding with a guy in France. In fact he was speaking about the noise floor and not phase noise. Very different .
Really I like always your different reaction which are always positive and constructive.

I will soon give a little report about cybershaft psu upgrade.
 

SCAudiophile

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Sep 11, 2010
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As usual , complete information Thank you.
In fact I had a misunderstanding with a guy in France. In fact he was speaking about the noise floor and not phase noise. Very different .
Really I like always your different reaction which are always positive and constructive.

I will soon give a little report about cybershaft psu upgrade.
Thank you,...always glad to help where I can. There are some excellent implementations out there in the market.
 

antigrunge

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Jan 17, 2022
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When comparing clocks paying attention to the BNC cables used is important. Other than obviously using the correct ohmage, avoiding any source of vibration on the cable is crucial. My best results come from using Black Ravioli pads as dampers at both ends. Every little bit counts….
 
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QuadDiffuser

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A TCP/IP "audiophile" network switch does not necessarily perform better with an external "precision" clock connected, particularly when 'mediocre' power supplies and cables are used, as demonstrated by quantitative measurements shown in this video.

As with all things High End audio, there are multiple variables of which any can inadvertently become the weakest link... implementation matters a lot. In the realm of clocking devices, something which appears benign (such as cables, connectors and power supplies) can and will introduce potential sources of jitter despite of the "precision" of the clock itself. Without access to lab equipment revealing objective data, it's easy to be fooled by the power of FOMO and persuasion.

In my setup, I'm grateful to say that I've had the privilege of an in-house audition of the Cybershaft OP21a in my own system before pulling the trigger, and verified the positive changes, so no regrets whatsoever.
 
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Kris

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A TCP/IP "audiophile" network switch does not necessarily perform better with an external "precision" clock connected, particularly when 'mediocre' power supplies and cables are used, as demonstrated by quantitative measurements shown in this video.

As with all things High End audio, there are multiple variables of which any can inadvertently become the weakest link... implementation matters a lot. In the realm of clocking devices, something which appears benign (such as cables, connectors and power supplies) can and will introduce potential sources of jitter despite of the "precision" of the clock itself. Without access to lab equipment revealing objective data, it's easy to be fooled by the power of FOMO and persuasion.

In my setup, I'm grateful to say that I've had the privilege of an in-house audition of the Cybershaft OP21a in my own system before pulling the trigger, and verified the positive changes, so no regrets whatsoever.
It is also system dependent
I tested it myself 3 times with 2 different brands in my system.
I always preferred the no additional clock solution.
The closer the clock is the better.
If you need a 1m cable and 2 cicuits on both ends the overall benefit might be covered
with additional noise you are adding with that link.
So always test it yourself.
 

antigrunge

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Jan 17, 2022
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Not sure the video proves anything other than the fact that cheap Chinese clocks may have more phase noise than the Volumio’s internal clock. In my experience reclocking the Etherregen with an Antelope 10m clock has easily demonstrable benefits amply defeating the presenter’s thesis
 

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