It's not up to me to decide on this, but I think it would make sense to split up this thread into a thread about the original subject, how to make an extremely low phase noise oscillator, and a thread about how useful or useless low phase noise oscillators are for audio. I'm not sure what part the little discussion about clock subharmonics that I started in post #2830 belongs to.
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D
Deleted member 537459
from the age of 13 that I have cultivated a passion for audio, from the age of 17 that I work in a car audio shop, I have been in the home sector for about 10 years and I have been building, assembling and modifying electronics for about 5 years audio. I collaborate with one of the most advanced companies in the electronic sector, CAEN spa Italy. I have been working for about 3 years to develop the best ethernet network for liquid music, therefore I have been modifying Ethernet switches with relative oscillator changes. and clearly oscillator in the switch. after years of continuous search for the best possible clock for the switch, having also tried masterclock with various pll etc. I preferred the clock raltron 5000. also from a masterclock from around 7000 €. everything stopped until Andrea creates his oscillators. try it on my ethernet network and boom! a notable difference, perhaps it is an idea, a belief as some of you (probably deaf) say. I can tell you that friends, passionate companions and customers have also felt the improvement, and the best test to understand what is better is to do a blind test where the listener does not know what he is listening to and tells you his feelings. but the increase in overall silence in the system, the increase in bass extension is irrefutable and beyond measure in my opinion. it's like comparing a good power cable to a basic one ... we can't measure the differences on an instrumental level but only by ear, this is also a perception !? only a fool full of convictions and prejudices can deny the evidence. this is my experience on Andrea's work. comes from more than 20 years of audio. @ syn08 and companions, you are misrepresenting this forum, this is an audio forum and as such most of it cannot be measured but only heard and synergy found in the components. you can take a McIntosh or Krell amplifier with measurements that may be the same but at a completely different sound level ... which one is better! ??? please, if you are so good and intelligent make your thread and your products, we will be happy to hear your items. hoping not to read you again I wish you a good day
I have done a test, upon the inspiration of HP (of the fame of HPWorks). And here I would like to thank him. It's the zoom in to the close-in zone, on the actual audio dac output, and confronting two different dac's with different clocking systems.
The registration of the output signal had been done with the RTX6001.
The red trace is the Topping D90, using an AK4499+Accusilicon AS318-B 45,158MHz XO.
The blue trace is my Yanasan kit, (AK4499 dual mono), with TWTMC DRIXO 22,579MHz external clock input.
The central frequency setting had been sligthly shifted beetween the two tracks, hence the visible shift.
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Just for the record (and balance) and not as reply to anyone in specific:
The Andrea 5,6Mhz Oscillator together With Ian's FiFoPi was one of the better investments I made this year and I thank both for their work and making it available. Listening to my music has notched up in joy. And that is what is about. Please refrain from any belittling and placebo comments
- I think I got it by now and I just don't care; I am just minding my own stuff and pleasure, so should everyone 
The Andrea 5,6Mhz Oscillator together With Ian's FiFoPi was one of the better investments I made this year and I thank both for their work and making it available. Listening to my music has notched up in joy. And that is what is about. Please refrain from any belittling and placebo comments
- I think I got it by now and I just don't care; I am just minding my own stuff and pleasure, so should everyone No, he’s right. This forum reads like Head-Fi on Andrea’s threads when his claims aren’t challenged by scientifically minded posters. Head-fi is glorified advertising as a forum.
So? I have invested in a clock of Andrea, with demonstrated, as in measured high quality parameters. I have tested myself that his claims are true. I have tested and see that this clock brings a measurable better response on the audio output of my system.
So, Can You try and search at least a tiny crumble of reason in Your rant, which should stop me obtaining this effect, and stop Andrea providing something that permits it!?
Could just go away and leave us in peace!!!?
So, Can You try and search at least a tiny crumble of reason in Your rant, which should stop me obtaining this effect, and stop Andrea providing something that permits it!?
Could just go away and leave us in peace!!!?
Joseph,
BRILLENT work - Clearly showing the typical effect of "close-in" Clock domain phase noise...
Good going JK! But to be really sure, the measurement had needed to be done on the one and the same DAC bord with the different clocks coming in to the DAC board via the same interface - now layout etc might have an impact... sorry to be picky but we are in -110..-140dB dB territory - one has the right to be - no?
I would lie to add that I don't doubt the results but just to make a clear case...
//
I would lie to add that I don't doubt the results but just to make a clear case...
//
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TNT,
Yes, absolutely, That part is coming - I have to set up a more general interface for the classic, simple XO-s..
Their drive capability is not comparable to the TWTMC, (no way to drive a correct 50ohm load with a can oscillator..) so I was using a quite different config, when using my NDK SDA clocks for the Yanasan kit.
Now I have to do a correct buffer/driver stage for those Cmos thingies..
Yes, absolutely, That part is coming - I have to set up a more general interface for the classic, simple XO-s..
Their drive capability is not comparable to the TWTMC, (no way to drive a correct 50ohm load with a can oscillator..) so I was using a quite different config, when using my NDK SDA clocks for the Yanasan kit.
Now I have to do a correct buffer/driver stage for those Cmos thingies..
Hi George,
thanks for the tribute to Pat.
The one to the right of the picture is me, a perfect idiot.
To the left of the picture is Pat Di Giacomo alias Jocko Homo, a wonderful person, a brilliant guy, a very smart engineer, an open mind.
Thanks Pat for what you taught us.
R.I.P.
I don't know why he was banned, but having seen the last 40 pages of this thread I can now clearly imagine it.
I've asked several times to replace the word "Banned" with "R.I.P." on his profile.
No succes.
I am very sad about this.
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Cool that you managed to measure the skirts at audio frequencies! For my understanding, you are playing back a 398.36 Hz sine wave at 48 kHz sample rate and measuring the spectrum from 37.5 Hz below to 37.5 Hz above the 398.36 Hz centre frequency?
It surprises me that you see anything at all at such a low audio frequency. Maybe my simple frequency divider theory is too simple.
Oops, Marcel. To be precise, I drive the dacs at 352,8kHz equivalent speed. Only the data acquisition is happening at 48kHz, so as to obtain the least possible ADC jitter contribution.
Though I would like to underline, that I have tried it also with 44,1kHz, PCM drive for the Topping, and the result is not significantly different. (Sligthly, yes)
Though I would like to underline, that I have tried it also with 44,1kHz, PCM drive for the Topping, and the result is not significantly different. (Sligthly, yes)
I wonder if you see a dependence on the audio frequency. If not, maybe there is some conversion from the clock phase to the output signal amplitude going on that produces much stronger sidebands than the phase modulation of the audio signal. I have no idea what exactly would cause that in the AK4499 switched resistor DACs, though.
Excellent work Joseph & Andrea!!
It's what is always talked about but not usually graphed so accurately - the spectral spreading of a fundamental tone due to close-in phase noise.
At the risk of being abused (by some on this thread) can I offer my simplistic thoughts on how this spectral spreading might translate into auditory perception?
Distance of auditory objects is influenced by sound spectrum (Frontiers | Sound Spectrum Influences Auditory Distance Perception of Sound Sources Located in a Room Environment | Psychology). If we have a fluctuating sound spectrum over time (as would result from spectral spreading) our auditory system is less able to determine a precise location of all the auditory objects in a soundfield. Less spectral spreading of all the frequencies that make up a soundfield should result in more precise auditory localisation of each auditory object in that soundfield & as a result a perception of a more solid & realistic auditory image.
This seems to be what is reported when using oscillators of lower close-in phase noise (i.e less spectral spreading in the resultant analog output)?
It's what is always talked about but not usually graphed so accurately - the spectral spreading of a fundamental tone due to close-in phase noise.
At the risk of being abused (by some on this thread) can I offer my simplistic thoughts on how this spectral spreading might translate into auditory perception?
Distance of auditory objects is influenced by sound spectrum (Frontiers | Sound Spectrum Influences Auditory Distance Perception of Sound Sources Located in a Room Environment | Psychology). If we have a fluctuating sound spectrum over time (as would result from spectral spreading) our auditory system is less able to determine a precise location of all the auditory objects in a soundfield. Less spectral spreading of all the frequencies that make up a soundfield should result in more precise auditory localisation of each auditory object in that soundfield & as a result a perception of a more solid & realistic auditory image.
This seems to be what is reported when using oscillators of lower close-in phase noise (i.e less spectral spreading in the resultant analog output)?
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