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DC blocking capacitors audibility.

MaxwellsEq

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Such in doubt. I have to guess there isn't many people on the forum that went to electronics school. Nor some that got into researching micro-anomalies with parts. I find that the info on a lot of electronic subjects have been streamlined on the internet compared to my college text books that were written 30+ years ago.

So is this what people do now these days instead of talking about a subject : Find an argument that supports theirs, or find someone's research, and not questioning it nor discussion, just accepting one and discounting others or just blatantly assume and voice that they are wrong. I am a scientist of electronics, so I am always trying to find answer, in a construct of very few physical laws compared to its theories and always question and look for topics that should be a discussion instead of settling on one or another person's findings.

Can anyone explain the noise generated in the regulator circuit mathematically that is caused by using a ceramic bypass cap compared to a MLCC type cap used in the same place?
I doubt it because no one has figured out how to apply a math formula to it. Just observed the phenomenon.
What are you trying to clarify?

Instead of having waffling long paragraphs, make some simple short statements that are easy to understand. Perhaps you are onto something, but it is hard to follow you.

Remember that more than four decades ago components were packed into the Voyager spacecraft which are still working after years of high ionising & non-ionising radiation and big magnetic fields, but still they work. The designers were using the best known theory at the time, and it looks like their understanding was mostly right.

Please demonstrate what exactly has happened in the last forty years that changes our knowledge?
 

Salt

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Intel 8088 was in use because of it's resistance to radiation and others for years (centuries?) by NASA.
Would You prefere to use it in audio gear today?
 

MaxwellsEq

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Intel 8088 was in use because of it's resistance to radiation and others for years (centuries?) by NASA.
Would You prefere to use it in audio gear today?
That's a microprocessor, right? I don't believe this conversation has anything to do with microprocessors.

This is about how capacitors behave. Voyager has lots of analogue electronics, especially beautifully tuned discrete radio frequency engineering.
 

Salt

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... of the last century.
 

nutzandvoltz

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Well this is an interesting article on the subject:
Understanding the Frequency Characteristics of Capacitors, Relative to ESR and ESL

EDIT: This stands out, as I heard something similar before: "one should select the device according to the frequency characteristic of the impedance rather than the capacitance". But more precisely:"one should select the device according to the frequency characteristic of the impedance, rather than its capacitance tolerance".
 
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MaxwellsEq

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Well this is an interesting article on the subject:
Understanding the Frequency Characteristics of Capacitors, Relative to ESR and ESL

EDIT: This stands out, as I heard something similar before: "one should select the device according to the frequency characteristic of the impedance rather than the capacitance". But more precisely:"one should select the device according to the frequency characteristic of the impedance, rather than its capacitance tolerance".
You either didn't read this article or you don't understand it. If you did read or understand it you would have noticed that this is about:
a) dumping HF/RF noise to ground (which has nothing to do with using a capacitor to block DC and ultra-low frequencies in a chain) and
b) the graphs show totally expected behaviour in the audio ranges and are only interesting (and also predictable!) in the MEGA-Hertz ranges, which is important when selecting a capacitor for dumping noise to ground.

EMC-9_graf_03.gif


Every EE who has ever dealt with RF filtering knows about this behaviour! They knew about it more than 30 years ago, as well!
 

Ken Tajalli

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For what it is worth:
Comparing Chord Mojo classic and Mojo 2, there is a distinct tonal difference between the two, Mojo classic sounds a little dull compared to Mojo2.
Also, Mojo2 has a drier bass. I know, I know, subjective views! Many reported these aspects when the unit first came out, some liked it, some didn't!
Yet both have ruler flat FR.
Eventually, Rob Watts came clean and put the blame on a DC blocker capacitor that was used on the classic, but replaced with a servo on the Mojo2.
The difference is very audible.
 

MaxwellsEq

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For what it is worth:
Comparing Chord Mojo classic and Mojo 2, there is a distinct tonal difference between the two, Mojo classic sounds a little dull compared to Mojo2.
Also, Mojo2 has a drier bass. I know, I know, subjective views! Many reported these aspects when the unit first came out, some liked it, some didn't!
Yet both have ruler flat FR.
Eventually, Rob Watts came clean and put the blame on a DC blocker capacitor that was used on the classic, but replaced with a servo on the Mojo2.
The difference is very audible.
You may find this thread interesting. Short summary:
"df metric" has allegedly a good alignment with subjective opinions.
They demonstrate significantly different df metric values with two devices which both measure well in the classic 20Hz and 20kHz range.
As the thread has continued it's become clear that df metric has a strong bias to scoring phase differences at LF.

So is df metric scoring things that are not relevant or is LF phase behaviour due to capacitor-coupled devices audible?

 

SIY

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For what it is worth:
Comparing Chord Mojo classic and Mojo 2, there is a distinct tonal difference between the two, Mojo classic sounds a little dull compared to Mojo2.
Also, Mojo2 has a drier bass. I know, I know, subjective views! Many reported these aspects when the unit first came out, some liked it, some didn't!
Yet both have ruler flat FR.
Eventually, Rob Watts came clean and put the blame on a DC blocker capacitor that was used on the classic, but replaced with a servo on the Mojo2.
The difference is very audible.
Can I assume that none of this "comparing" was done with basic controls?
 

BDWoody

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I have to guess there isn't many people on the forum that went to electronics school..

You are guessing wrong.

You have no idea who you are talking with. Stop with the 'smartest guy in the room' thing, and speak as though the people you are talking with are EEs and PhDs who actually know the equations (because they are).
 

nutzandvoltz

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You either didn't read this article or you don't understand it. If you did read or understand it you would have noticed that this is about:
a) dumping HF/RF noise to ground (which has nothing to do with using a capacitor to block DC and ultra-low frequencies in a chain) and
b) the graphs show totally expected behaviour in the audio ranges and are only interesting (and also predictable!) in the MEGA-Hertz ranges, which is important when selecting a capacitor for dumping noise to ground.

View attachment 320692

Every EE who has ever dealt with RF filtering knows about this behaviour! They knew about it more than 30 years ago, as well!
So what still applies to the signal's current returning to common?
 

nutzandvoltz

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You are guessing wrong.

You have no idea who you are talking with. Stop with the 'smartest guy in the room' thing, and speak as though the people you are talking with are EEs and PhDs who actually know the equations (because they are).
Then people should discuss instead of being condescending.

I wasn't guessing anything. I want a discussion. That is different.
 

BDWoody

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Then people should discuss instead of being condescending.

I wasn't guessing anything. I want a discussion. That is different.

You said...

I have to guess there isn't many people on the forum that went to electronics school.

Not only is that pretty condescending, it's a strange way to start a discussion.

I think you'll find many here who are both incredibly knowledgeable, and very willing to explain subjects at a graduate level, but most aren't big on being dismissed quite so casually, particularly from sometime who has shown his command of the basics is in question.

Just... Take a deep breath
 

IAtaman

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Can anyone explain the noise generated in the regulator circuit mathematically that is caused by using a ceramic bypass cap compared to a MLCC type cap used in the same place?
Lower ESL of MLCC?
 

IAtaman

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Then people should discuss instead of being condescending.

I wasn't guessing anything. I want a discussion. That is different.
Wait a second. You started with a claim that caps have magnetic fields. Then it was pointed out to you that magnetic fields are created by moving charges. Later you posted a link to an article that talks about RF noise of caps as if it was new science. Maybe the problem is what you do does not come across like someone who wants a discussion but wants to prove a point no matter what. Maybe if you made a claim, explain why you made that claim, and support your explanation with factual information, the conversation would be more conducive to a discussion, notwithstanding the general frustration of ASR crowd having the same conversation for the last 10 years.
 
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fpitas

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notwithstanding the general frustration of ASR crowd having the same conversation for the last 10 years
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^!!!!
 

nutzandvoltz

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Lower ESL of MLCC?
I thought of that for the longest time. But operating frequency also seems to be a variable to the noise sympathetically generated.
It seems that you have to bode plot the caps that you are going to use to study based on dielectric for its frequency based distortion it generates.
Which ideally I would think you would try to use the lowest distortion profile for a coupling capacitor.
Does people consider relative phase shift an issue with coupling capacitors? Especially like in capacitor coupled balanced circuits where there is two coupling caps.
 

nutzandvoltz

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Wait a second. You started with a claim that caps have magnetic fields.

I used it as an ice breaker because its a conundrum.

It creates one due to the laws of induction but gets cancelled out internally. But this is based on mathematical models with ideal dielectrics instead of real models.
 

MaxwellsEq

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So what still applies to the signal's current returning to common?
??????????????

Can you rephrase? The question makes no sense.

Let me reiterate. The thread title is "DC blocking capacitors audibility". Firstly DC blocking capacitors are in a series context - the AC passes through them and the DC and extremely low frequencies do not. Secondly, in some situations, which have absolutely nothing to do with blocking DC, capacitors are used to offer unwanted very high frequencies a "cheap" path to ground discouraging their onward travel. You either have to stick to the thread title and start a different one on noise suppression or stop trying to introduce a different subject altogether in this DC blocking thread.
 

nutzandvoltz

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??????????????

Can you rephrase? The question makes no sense.
I will rephrase it in EIA electron theory terms:
What characteristics apply in AC analysis of coupling capacitors?
What characteristics apply in DC analysis of coupling capacitors?
Other questions fallow:
Is your analysis based on an operating impedance, or a total short? or do you look at both in consideration?
 
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