holy #@$#@%.@!!!!!
That's an expensive clock...
Yeah my audio buddy said:
...well Erik if I understand it correctly we now went from an 80 cent resonator to an 800 dollar clock...
I will give them a try soon
Why did I get the feeling that you would say something like that. Looking forward to hearing your observations.
Am I right that the page you showed is for "10 Mhz only" considering the "nature"......the Shiga uses as you know 16.93 Mhz...
All the ebay stuff I came across was not of any use either...
This 16.93 Mhz was quite a problem in my extensive search to try to obtain/implement the (Rubidium/Atomic) best clock possible (not exceeding my "clock-budget" of lets say 1500 dollar)...and if you do find a suitable one how will it perform...(experience somewhere)...a bit expensive to gamble...high stakes...
For the time being the Dexa was and proved a safe bet for me...
I will even buy it for myself.
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Originally posted by CraigBuckingham
Those recording engineers are misguided.
Rubidium master clocks are optimised for good long-term stability as time references. Very short-term stability or phase noise that is in the low end of the audio band is therefore not as critical a design parameter.
Current state of the art crystal oscillators are virtually at the limits that physics dictates for the type or resonator used. SC cuts performing better than AT cuts.
Rubidium master clocks use a CRYSTAL OSCILLATOR stabilised to the rubidium hyperfine transition of 6 834 682 610.904 324 Hz. It is that hyperfine transition frequency accuracy that gives long-term accuracy by the use of synchronising to it.
The short-term accuracy is determined by the CRYSTAL OSCILLATOR used in the rubidium standard.
A brief description on that can be found here Rubidium standard - Wikipedia, the free encyclopedia
A more detailed description here PRS10 - Rubidium Frequency Standard
So to put it in simple terms the Rubidium standard oscillator is superfluous, redundant - lowers performance and adds unnecessary cost when applied to high quality audio/digital conversion.
MAYBE SOME INTERESTING STUFF TO READ IF YOU WANT TO KNOW MORE ABOUT CLOCKS
Those recording engineers are misguided.
Rubidium master clocks are optimised for good long-term stability as time references. Very short-term stability or phase noise that is in the low end of the audio band is therefore not as critical a design parameter.
Current state of the art crystal oscillators are virtually at the limits that physics dictates for the type or resonator used. SC cuts performing better than AT cuts.
Rubidium master clocks use a CRYSTAL OSCILLATOR stabilised to the rubidium hyperfine transition of 6 834 682 610.904 324 Hz. It is that hyperfine transition frequency accuracy that gives long-term accuracy by the use of synchronising to it.
The short-term accuracy is determined by the CRYSTAL OSCILLATOR used in the rubidium standard.
A brief description on that can be found here Rubidium standard - Wikipedia, the free encyclopedia
A more detailed description here PRS10 - Rubidium Frequency Standard
So to put it in simple terms the Rubidium standard oscillator is superfluous, redundant - lowers performance and adds unnecessary cost when applied to high quality audio/digital conversion.
Code:
MAYBE SOME INTERESTING STUFF TO READ IF YOU WANT TO KNOW MORE ABOUT CLOCKS
Did we conclude that 19.58 mm is the optimal distance? I measured one of my mechanisms and I have 19.6088 mm. Wasn't sure if that was enough of a differnce to worry about.
@Peter: Q902 is in place, trace cut and checked several times. Still no reaction... What could be the next step to look?
First, I would go back to original setup and see if the transport still working properly.
No LED on PS board
Tibi, I've started putting my ready mount version of the Shigaclone together. The first thing I did was wire up the transformer and PS board as shown in the instructions. When I plugged it in, I got 7.90 VDC at the output of the PS board, but the LED is not lit. I'm reading 12.6 VDC in one direction across the LED and 9.60 VDC in the other.
A the input to the PS board, I'm showing from Brown to White to Blue - 0 -11-22 VAC,
When I lightly touch the outer side of the LED (the one closest to the edge of the board) with a DMM probe I see the LED flicker slghtly.
Tibi, I've started putting my ready mount version of the Shigaclone together. The first thing I did was wire up the transformer and PS board as shown in the instructions. When I plugged it in, I got 7.90 VDC at the output of the PS board, but the LED is not lit. I'm reading 12.6 VDC in one direction across the LED and 9.60 VDC in the other.
A the input to the PS board, I'm showing from Brown to White to Blue - 0 -11-22 VAC,
When I lightly touch the outer side of the LED (the one closest to the edge of the board) with a DMM probe I see the LED flicker slghtly.
It is THAT good...
Anyway I am open minded...so if you know any DIY-er on earth with such an atomic clock...
I have been asking around for the last two years on internet...and I only came via Australie on a japanese implemented it who does not correspond...
Since the clock-outcome was crystal clear and easily available in minutes I experimented with your resistors...GREAT SUCCES
First I implemented the 100 Ohm as a Shunt replacing a naked Vishay..in a winning Pi-Pad config....yours made more music it was even simple to notice....
After that me and my audiomate (who had the same opinion) went to your resistor 300 Ohm for serie and 100 Ohm for shunt althought I had no extra 100 ohm of yours at hand to make a Pi-Pad your combo was the star of the evening...we later on added a Vishay to your combo this time a Pi-Pad config and that was just a little bit better...so I need to buy a couple of your resistors to make a Pi-Pad...
I would love to get my hands on some more of your 300 and 100 Ohm resistors could you PM me I want to pay for your stuff I received etc.......they STAY
I will post soon a few pics and do some more experimenting with your stuff...this forum is slightly ahead of the dutch where I post and then link to.....
Hi Erik, I am very glad you are so enthusiastic about my resistors. My claim to being the maker of the best resistors in the world is safe for now it seems
I do regret they have to be so expensive though, I would love it if more people could afford them...
Regarding the Pi-pads, I did a quick test, and I am quite confident that my suggested Pi-pad values (i.e. 125-139-125) perform better than 100-300-100. I am yet to try the solution suggested on the Polish forums. I will of course accept the the return on the resistors you have - should you decide to send them back after all
I will send you a PM in a minute.And I am of course eagerly awaiting the results of your C906 capacitor test
Am I right that the page you showed is for "10 Mhz only" considering the "nature"......the Shiga uses as you know 16.93 Mhz...
All the ebay stuff I came across was not of any use either...
This 16.93 Mhz was quite a problem in my extensive search to try to obtain/implement the (Rubidium/Atomic) best clock possible (not exceeding my "clock-budget" of lets say 1500 dollar)...and if you do find a suitable one how will it perform...(experience somewhere)...a bit expensive to gamble...high stakes...
For the time being the Dexa was and proved a safe bet for me...
I will even buy it for myself.
I did not check the frequency or its engineering merits because it never occurred to me that you might take my suggestion seriously
And you just went and actually wanted to buy the damn thing, despite it costing nigh on 1K$! Erik, have mercy on us, mere mortals lol!
That is interesting, I am wondering if my problem has anything to do with that... When I installed the Bobken reg and split the 5V line, my laser assembly became very noisy - the "tweeting" is loud enough to be distracting during quiet passages. I assumed it was something I did while modifying (knocked it or something), but maybe more current is the way to go... I am using a 3.9R Kiwame for current setting at the moment.
I'm selling my backup RC-EZ31. See post here:
http://www.diyaudio.com/forums/swap-meet/231290-fs-jvc-rc-ez31-shigaclone-boombox.html#post3394651
Regards,
Dan
http://www.diyaudio.com/forums/swap-meet/231290-fs-jvc-rc-ez31-shigaclone-boombox.html#post3394651
Regards,
Dan
U2 and heatsink
I note in the instructions a heatsink is recommended for U2. I've been wondering how effective this can be, since U2 is on what in most assemblies will be the underside of the main PCB. How is the heat supposed to convect off the sink if it's covered by the PCB?
Also, if a heat sink is used it looks like a thermal epoxy rather than regular thermal grease will be needed, as there is no way to mechanically mount a heat sink here. Ah, I see these are adhesive backed sinks. Guess that answers that part.
The last thing is that at least in the pictures I've seen so far in this thread, it looks like many PCBs do not have the heat sink installed. Is the heat sink mandatory or optional?
I note in the instructions a heatsink is recommended for U2. I've been wondering how effective this can be, since U2 is on what in most assemblies will be the underside of the main PCB. How is the heat supposed to convect off the sink if it's covered by the PCB?
Also, if a heat sink is used it looks like a thermal epoxy rather than regular thermal grease will be needed, as there is no way to mechanically mount a heat sink here. Ah, I see these are adhesive backed sinks. Guess that answers that part.
The last thing is that at least in the pictures I've seen so far in this thread, it looks like many PCBs do not have the heat sink installed. Is the heat sink mandatory or optional?