Hi Bill,
You are absolutely right on all counts. Thank you for clearing the air. However, we can moderate in cases where there is minor mechanical work to do (fix a post) or a major infraction. However we do simply ask another moderator to come in an have a peek so they can deal with the situation with anything beyond minor tweaks.
-Chris
You are absolutely right on all counts. Thank you for clearing the air. However, we can moderate in cases where there is minor mechanical work to do (fix a post) or a major infraction. However we do simply ask another moderator to come in an have a peek so they can deal with the situation with anything beyond minor tweaks.
-Chris
Hi Joseph K,
Nice work. I also have and RTX 6001, but haven't had the time for that testing. It would be interesting to see just a clock change as was mentioned earlier.
What was your signal source (file)? I guess too. the next step could be to figure out if the improvement was audible in any way. My suspicions would be that a poor quality clock being replaced with a good one might be. But something half decent being replaced may not result in something you could hear / sense.
Anyway, many thanks for performing that test. At some point I would like to do something similar to what you have done, hence my questions. I'd like to see how close I can come to your results.
-Chris
Nice work. I also have and RTX 6001, but haven't had the time for that testing. It would be interesting to see just a clock change as was mentioned earlier.
What was your signal source (file)? I guess too. the next step could be to figure out if the improvement was audible in any way. My suspicions would be that a poor quality clock being replaced with a good one might be. But something half decent being replaced may not result in something you could hear / sense.
Anyway, many thanks for performing that test. At some point I would like to do something similar to what you have done, hence my questions. I'd like to see how close I can come to your results.
-Chris
Something like a fixed dead time might cause a conversion from momentary clock frequency to output signal amplitude: the higher the frequency, the larger the percentage of the time that the DAC would be in the dead time and the smaller the output signal. However, you would then expect a 1/foffset and a flat part in the sidebands, not those steep slopes that Joseph measures.
Hi sebbyp,
Well, you are making guesses and drawing conclusions from next to zero information.
I am not competing with Andrea and have no plans to do so. I do not do clock upgrades because the equipment I work on have good clocks already. So far from what I have seen, only cheap DACs and CD players have poor quality clocks. They are not worth upgrading because they have all kinds of short comings.
I've been doing this for over 45 years. I don't advertise, nor do I do internet sales. I work on all kinds of audio equipment and my upgrades often involve circuit changes and improvements beginning with power supplies. I match transistors using a specially designed jig that I did release to the audio community and along with hand selected components, I can greatly improve most pieces of audio equipment. I also align tuners and improve them. So, you can see that my business model does not conflict with Andrea's work - but I do know a lot about it.
My bench equipment is mostly HP / Agilent / Keysight, so pretty darned good. The equipment that can use an external clock is frequency locked together using a 10 MHz source and proper clock distribution amplifier (HP 5087A), which is disciplined to the GPS network. When making careful measurements, the GPS receiver is put into hold-over mode, which means that it doesn't make any frequency corrections during the course of the measurement time. I also have calibration lab experience and am a Journeyman calibration / repair technician for electronic test equipment of the type we all use.
My questions are not an attack at all, but rather concerns about unanswered questions that affect you and also the usefulness of this oscillator. Not once have I questioned the quality of Andrea's oscillator. The only things I have done were to question the claims made as Andrea does not appear to have determined any metrics related to what he has sold these oscillators to improve. This should concern you.
I have not seen any "as found" and after data from any system Andrea claims to have improved in his research. This is very basic experimental procedure that everyone here learned in high school. So basic that I am concerned that Andrea does not understand anything about the systems he is "improving". I have been very open and honest about this the entire time.
-Chris
Well, you are making guesses and drawing conclusions from next to zero information.
I am not competing with Andrea and have no plans to do so. I do not do clock upgrades because the equipment I work on have good clocks already. So far from what I have seen, only cheap DACs and CD players have poor quality clocks. They are not worth upgrading because they have all kinds of short comings.
I've been doing this for over 45 years. I don't advertise, nor do I do internet sales. I work on all kinds of audio equipment and my upgrades often involve circuit changes and improvements beginning with power supplies. I match transistors using a specially designed jig that I did release to the audio community and along with hand selected components, I can greatly improve most pieces of audio equipment. I also align tuners and improve them. So, you can see that my business model does not conflict with Andrea's work - but I do know a lot about it.
My bench equipment is mostly HP / Agilent / Keysight, so pretty darned good. The equipment that can use an external clock is frequency locked together using a 10 MHz source and proper clock distribution amplifier (HP 5087A), which is disciplined to the GPS network. When making careful measurements, the GPS receiver is put into hold-over mode, which means that it doesn't make any frequency corrections during the course of the measurement time. I also have calibration lab experience and am a Journeyman calibration / repair technician for electronic test equipment of the type we all use.
My questions are not an attack at all, but rather concerns about unanswered questions that affect you and also the usefulness of this oscillator. Not once have I questioned the quality of Andrea's oscillator. The only things I have done were to question the claims made as Andrea does not appear to have determined any metrics related to what he has sold these oscillators to improve. This should concern you.
I have not seen any "as found" and after data from any system Andrea claims to have improved in his research. This is very basic experimental procedure that everyone here learned in high school. So basic that I am concerned that Andrea does not understand anything about the systems he is "improving". I have been very open and honest about this the entire time.
-Chris
We does not understand anything about the systems we are "improving", less than zero, but we are so presumptuous that we also are designing the digital front end (FIFO buffer) and the DAC (the systems to be improved).
But as I have already said I'm (we are) a perfect idiot.
So maybe we think we're designing a system to convert digital signals to analog, but we're actually building a microwave oven.
But as I have already said I'm (we are) a perfect idiot.
So maybe we think we're designing a system to convert digital signals to analog, but we're actually building a microwave oven.
Marcel,
Rohde & Schwarz UPD & UPL (not sure about the latest UPV) feature Zoom FFT function allowing you to perform an 8K FFT over very narrow Spans - making them a great tool to perform such close in measurements...
With this zoom FFT mode its very easy to see such clock realated "Side skirts" and odd ASRC behavoiur etc...
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They are competitive
, as they're aiming to achieve the same thing. Improve a digital audio product. An easier to understand example. You are Blockbusters and Andrea is Netflix. You are holding on to your 45 years of knowledge and refusing to accept new concepts. So you attack the new innovative solution. When you find the general opinion differs to you, to sleep at night you have attacked those people too. To make it worse you have then begun a campaign against your competitor to hold them to a bar that's unachievable. If Andrea had a genuine business, he would be opening a case for slander.
You must think we are idiots. Oh wait, you have repeatedly told us that we are.
Thats a great story Chris, but I don't think anyone's interested. This is a thread about Andrea's clocks, not your biography or a place to advertise the services and tools you do deliver (yet again in the post above). Open a post in the vendor forums.
Can you either call on the mythological power of Zeus, power up to moderator and clean up this thread. Or call in a moderator to remove this post, your post and the rest of the misinformation in here please.
If you want to continue this rhetoric please leave and open a post elsewhere to question the ability to hear the reduction in whatever criteria you don't agree with. If you don't and you actually want to contribute, I don't think anyone would mind your presence if you stayed on topic and began utilising common courtesy.
I would have thought this is 101 for an esteemed moderator, but I suppose that went out the window when you broke the first rule of the forum.
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Joseph sees -126 dBc in 1 Hz at 10 Hz offset from a 398.36 Hz signal where I expected something like -180 dBc in 1 Hz at 10 Hz offset from a 20 kHz signal and even less at lower signal frequencies. Clearly my frequency divider theory doesn't quite fit with reality.
What alternative conversion mechanisms from clock sidebands to audio signal sidebands can you come up with?
yes, indeed! those active rectifier bridges are superior to the conventional passive ones probably everywhere. a friend of mine suggested them to me long time ago and i have been using them in digital and analog sections replacing my old passive rectifiers with very positive results! everybody should try them
Ok, I have not finished the reading, yet, but this paper could be useful..
https://www.google.com/url?sa=t&sou...Vaw2mlvIMonExrMHZb-IQBgcv&cshid=1625492549099
https://www.google.com/url?sa=t&sou...Vaw2mlvIMonExrMHZb-IQBgcv&cshid=1625492549099
That is presumptuous -.yes. It's much harder to design a DAC than making a clock.
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Marcel,
I'm not sure I follow your question, but with a 1 bit system there will be a 100% corrillation with clock Phase noise and demodulation in the audio BW, reflected off the "DC" component & any other signal components.
Higher modulator output bit depths (I'm guessing the AKM is 5bits or some such) reduce this - so a 5 bit system would be 30dB less sensative to clock phase noise then a 1 bit system...
Its also possible (when correctly implemented) with a multi-elment DAC array to decorrilate - ie "whiten" the energy of discrete phase noise spurie into wideband decorrliated noise - the energy within any discrete spurie is spread across the DAC array's clock bandwidth - so the wideband noise floor energy is increased, but as a result audiablly negative sounding Clock PN spurie components are decorrliated into "noise".
FFT on DAC Outputsignal - looking for skirts
I tried with Arta with a 24bit 192kHz ADC and also with my AP at low bandwidth and surpression of the main signal to gain extra headroom.
I used one and the same DAC and only swopped the standard cheap XO for the Andrea Clock
Unfortunately I could not produce anything meaningfull (just a small difference with the AP FFT)
anyway, still wanted to share it here
.
I tried with Arta with a 24bit 192kHz ADC and also with my AP at low bandwidth and surpression of the main signal to gain extra headroom.
I used one and the same DAC and only swopped the standard cheap XO for the Andrea Clock
Unfortunately I could not produce anything meaningfull (just a small difference with the AP FFT)
anyway, still wanted to share it here
.
Attachments
Hi Andrea,
Why don't you attempt to answer some basic questions. They are in your best interests after all.
I am not attacking your clock one little bit. Think about it for a second. I am asking you what problem you are trying to solve, that's all. Basic knowledge that anyone considering your product / invention should consider.
If you can't / won't answer these things, the only obvious conclusions can be that either it doesn't do much or anything to improve the average clock, or you don't understand the basics of what you are trying to do. Is your improved clock a solution looking for a problem?
-Chris
Why don't you attempt to answer some basic questions. They are in your best interests after all.
I am not attacking your clock one little bit. Think about it for a second. I am asking you what problem you are trying to solve, that's all. Basic knowledge that anyone considering your product / invention should consider.
If you can't / won't answer these things, the only obvious conclusions can be that either it doesn't do much or anything to improve the average clock, or you don't understand the basics of what you are trying to do. Is your improved clock a solution looking for a problem?
-Chris
You must realize the answer is in The Well Tempered Master Clock - Building a low phase noise/jitter crystal oscillator
Post #4311
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