Cable distortion and "micro diodes"

[Fred Dieckmann]

He's at it again..........

"Anyway, DA is a linear distortion (so basically it only affects frequency/phase response) but it's effect in things like audio cables is so insignificantly small it's totally swamped by the bulk capacitance of the cable."

What the in the heck is linear distortion
and how do you jump to the conclusions that follow?

'Hehehe. Ok, I won't. If you promise never to cite cable manufacturer websites as references."

I think you should only cite high end audio websites. The pseudo science, simplifications, and B.S. are right up your ally...... I guess there is no point in asking John Curl to straighten you out on capacitors. Proceed, at least this kind of stuff keeps you you busy enough to stay out of the useful threads.

 

[Steve Eddy]

Re: He's at it again..........

"Anyway, DA is a linear distortion (so basically it only affects frequency/phase response) but it's effect in things like audio cables is so insignificantly small it's totally swamped by the bulk capacitance of the cable."

What the in the heck is linear distortion

From http://www.daqarta.com/0d00dist.htm :

Distortion is classified as either linear or nonlinear. Linear distortion includes processes that may change the level or phase of a signal or its individual frequency components, but not add any new components. Ordinarily these processes would be described by their effects, such as "frequency response" or "phase shift", rather than "linear distortion".

And quoting John Curl:

Of course, Walt Jung and I were attempting to go beyond just harmonic distortion measurements, and found the DA could be 100 times or more higher than harmonic distortion, but that it must be defined as a 'linear' distortion.

So I defined it as a "linear distortion."

and how do you jump to the conclusions that follow?

From the DA model. And from a rather terse response from Bob Pease:

Steve, lets' say a 100 ft stretch of speaker cable has 1000 pf. The soakage of a mylar cap of that size would be about 10 pF in series with 1 meg.

You drive this from an amplifer whose output impedance is lower than 1 ohm. In concept if you put this in a precision measuremnt system, you could measure perhaps as low as 0.01 dB of attenuation.

(YOU MUST AGREE - you certainly can't HEAR that kind of attenuation shift, 0.01 dB...)

But the soakage of 1 megohm, is below the 0.01dB by about a factor of 1000. If you want to wast your time by arguing with audio nuts about things that are 1000:1 below the limits of MEASURABILITY - not to mention 100,000:1 below the limits of audibility --

-- BE MY GUEST, but don't waste MY time, OK?

Yeah, if you ran speaker cables not just 100 ft, but 10,000 ft. - and if you ran a rubber line cord that is perhaps 10 x worse than mylar - you might be able to measure it.

WHO CARES!

If you ran wire 900,000 feet, the soakage might IN CONCEPT become important, except the signal coming out the end would be distorted by some MUCH bigger effects, and the audio output would be INAUDIBLE.

Forget it.

"Hehehe. Ok, I won't. If you promise never to cite cable manufacturer websites as references."

I think you should only cite high end audio websites. The pseudo science, simplifications, and B.S. are right up your ally...... I guess there is no point in asking John Curl to straighten you out on capacitors.

You mean like how he straightened us out on cable distortion?

se

 

[sully]

Re: He's at it again..........

"Anyway, DA is a linear distortion (so basically it only affects frequency/phase response) but it's effect in things like audio cables is so insignificantly small it's totally swamped by the bulk capacitance of the cable."

What the in the heck is linear distortion
and how do you jump to the conclusions that follow?

I believe his statement meant that it only affected freq and phase?

And I believe he "jumps" to the conclusions that follow, based on real numbers of actual effects, combined with the actual capacitances of cables, and output impedance of drivers..but I assume that..

I think you should only cite high end audio websites. The pseudo science, simplifications, and B.S. are right up your ally......

What pseudo-science do you speak of? I seem to have missed that..

"I guess there is no point in asking John Curl to straighten you out on capacitors. Proceed, at least this kind of stuff keeps you you busy enough to stay out of the useful threads.

I'm confident that bulk devices can exhibit these effects..but, bulk devices are generally designed on the higher edge of the field gradient capabilities of the dielectric, to keep form factor reasonably down, along with cost..

Wires, on the other hand, always run extremely far down the dielectric capabilities..IC's will typically flashover in the hundreds to thousands of volts regime, while being asked to carry 1 to 10 volts..Capacitors rarely will survive voltage two to three orders of magnitude over their working voltage..

So, to BLINDLY assume that an effect which can be measured in a bulk capacitive device can be simply carried over to a wire, with it's three order of magnitude voltage gradient difference as well as it's three to five order (even more) capacitance difference and 6 to 9 order of magnitude energy storage density difference, is to, well, be blind..Anyone who states that capacitor issues will certainly also happen in wires...certainly needs to bring more to the table than you have done.. Do you have anything to substantiate your statement??? Data would be nice..

Proceed, at least this kind of stuff keeps you you busy enough to stay out of the useful threads.

You seem to have an ax to bear...is this a personality flaw, or a historical problem? (I'm new here)

Cheers, John

 

[Christer]

Now this is getting interesting and confusing

The usual way of modelling DA in capacitors it to parallel it
with RC links, and this is AFAIK an agreed on model which
is supported by a number of papers on this topic. Obviously
this means that a capacitor with DA is still a linear system and
thus cannot introduce any new frequency components, it can
only alter frequency and phase response, as Steve pointed
out. In my understanding, although I may be wrong on
terminology, this is not distorsion. Both I and others have
on several occasion asked, in light of this, how DA could
possibly cause distorsion in capacitors and nobody so far
has even given a serious attempt at answering this. (Note,
I am not saying there cannot be distorsion in capacitors, just
that DA seems not to be a possible reason for it). However,
I was somewhat surprised when John Curl some time ago
talked about DA and linear distorsion in some thread (which
one I cannot remember right now). I have always thought
that distorsion is by definition a non-linear phenomenon. I
don't think John ever explained what he meant, but since
he talked about DA causing linear distorsion, I assume he
uses the term linear distorsion for an altered frequency and
phase response. However, I think it would be best if John
himself could enlighten us what he mean by the term.

 

[Steve Eddy]

The usual way of modelling DA in capacitors it to parallel it
with RC links, and this is AFAIK an agreed on model which
is supported by a number of papers on this topic. Obviously
this means that a capacitor with DA is still a linear system and
thus cannot introduce any new frequency components, it can
only alter frequency and phase response, as Steve pointed
out. In my understanding, although I may be wrong on
terminology, this is not distorsion.

Technically, anything which unintentionally alters the signal is a distortion. So anything which unintentionally alters the magnitude of the frequency components of a signal or their relative phase would also be a distortion. And if such distortions are brought about by linear elements such as energy storage mechanisms like capacitance and inductance, you can rightly call it linear distortion.

se

 

[Fred Dieckmann]

It must be true then.

"a historical problem"

Go back and read a few of Mr. Eddy's past post and then come talk to me about his technical knowledge.

I have never heard of linear distortion in reference to electronics. To quote you're reference:

"Distortion is classified as either linear or nonlinear. Linear distortion includes processes that may change the level or phase of a signal or its individual frequency components, but not add any new components. Ordinarily these processes would be described by their effects, such as "frequency response" or "phase shift", rather than "linear distortion". "

Far be it from me to question a quote from a reputable source like INTERSTELLAR RESEARCH who do data acquisition software for soundcards, but I have never seen the seen the term in any electrical engineering text. i don't think I remember the term being used in Bob Pease's DA article (written 21 years ago)

http://www.national.com/rap/Application/0,1570,28,00.html

I also did not see the term in a more recent paper on modeling DA.

http://www.designers-guide.com/Modeling/da.pdf

P.S. I am not making claims that DA is audible in cables and have never heard of a "micro diode". I leave you to your disscussion of physics and electronics for poets.

 

[john curl]

I don't know where all this came from, but DA might have a non-linear component. This was measured by Cyril Bateman in his cap distortion articles in 'Electronics World'. Hysteresis itself, I think is a separately measurable nonlineartity, at least this is obvious with cheap ceraminc caps.

 

[Pjotr]

Let’s forget about DA. It is not something that generates harmonic distortion IMHO. When I brought up dielectric hysteresis here, I meant non-linear behaviour of capacitors. I remember from college that it exists and more in ceramic caps than in plastic film caps, but have forgotten the details. This is in agreement that ceramic caps in the audio signal path are not the first choice. But if cables can produce harmonic distortion it is has more likely to do with such mechanisms than with diodes IMHO.

Cheers

 

[Christer]

Technically, anything which unintentionally alters the signal is a distortion. So anything which unintentionally alters the magnitude of the frequency components of a signal or their relative phase would also be a distortion. And if such distortions are brought about by linear elements such as energy storage mechanisms like capacitance and inductance, you can rightly call it linear distortion.

se

Sure, from a logical/mathematical point of view it is a kind of
obvious definition to do, but I have never heard the term linear
distorsion until John used it recently, and Fred seemed puzzled
too, unless I misunderstood him. An amplifier always starts
to change its frequency and phase responese at some point,
although usually above the audio band and many also have
a coupling capacitor causing an LF roll-off. Yet, we never hear
of this referred to as distorsion. I also doubt this is the type
of distorsion people mean when they talk about capacitor
distorsion.

If we call anything that alters the signal distorsion, then also
noise is a kind of distorsion, or did you tacitly assume that
the altered signal must at least be a function of the input signal?

 

[Christer]

Let’s forget about DA. It is not something that generates harmonic distortion IMHO.

I don't even think that has to be a humble opinion
As I pointed out it is obvious from the standard model of
DA that it cannot produce any new harmonics, ie. no
(non-linear) distorsion.

When I brought up dielectric hysteresis I meant non-linear behaviour of capacitors. I remember from college that it exists and more in ceramic caps than in plastic film caps, but have forgotten the details.

Yes, ceramic capacitors are well-known to be non-linear. Film
caps are usually not considered non-linear AFAIK, but that is
of course according to usual textbook knowledge that
considers small non-linearities as negligible. Most probably
there is at least some degree of non-linearity also there, althoug
much smaller than for ceramics.

 

[Christer]

I don't know where all this came from, but DA might have a non-linear component. This was measured by Cyril Bateman in his cap distortion articles in 'Electronics World'. Hysteresis itself, I think is a separately measurable nonlineartity, at least this is obvious with cheap ceraminc caps.

So are you saying that the usual model of DA is not sufficiently
accurate? I won't protest, models are after all just models and
may be more or less accurate descriptions of reality. However,
I have got the impression that DA is fairly well understood in
theory and that theory and standard model correlates well in
this case. If Bateman just measured, how can we know the
cause of his results were DA and not some other phenomenon?

 

[sully]

Re: It must be true then.

"a historical problem"

Go back and read a few of Mr. Eddy's past post and then come talk to me about his technical knowledge.

Far be it from me to question a quote from a reputable source like INTERSTELLAR RESEARCH who do data acquisition software for soundcards,
P.S. I am not making claims that DA is audible in cables and have never heard of a "micro diode". I leave you to your disscussion of physics and electronics for poets.

Ah...so it was an historical problem...I don't care about that..I am only thinking of this thread..

Are you being facetious when you said "far be it....software for souncards? I won't respond to that until you clarify your intent..


What does a poet know about physics and electronics?

You confuse me with your off base references..(I must be easily confused)..

Cheers, John

 

[Steve Eddy]

Re: It must be true then.

I have never heard of linear distortion in reference to electronics. To quote you're reference:

"Distortion is classified as either linear or nonlinear. Linear distortion includes processes that may change the level or phase of a signal or its individual frequency components, but not add any new components. Ordinarily these processes would be described by their effects, such as "frequency response" or "phase shift", rather than "linear distortion". "

Far be it from me to question a quote from a reputable source like INTERSTELLAR RESEARCH who do data acquisition software for soundcards, but I have never seen the seen the term in any electrical engineering text. i don't think I remember the term being used in Bob Pease's DA article (written 21 years ago)

http://www.national.com/rap/Application/0,1570,28,00.html

I also did not see the term in a more recent paper on modeling DA.

http://www.designers-guide.com/Modeling/da.pdf

How 'bout this AES paper from Lavardin?

http://www.lavardin.com/aesE.html

The classical theoretical model of an audio power amplifier is the base for measuring amplifier distortion. It is made up of a perfect amplifier and two distortion generators : the linear distortion generator corresponds to the amplitude, phase, phase-slope and group delay modifications resulting from the band limitations of a real amplifier ; the non-linear distorsion generator corresponds to the non-linear transfer characteristique of a real amplifier.

Or how 'bout this from Linkwitz Labs?

http://www.linkwitzlab.com/mid_dist.htm

For the PHOENIX main panel I use a set of 8" (21 cm) drivers, Scan Speak 21W/8554, which were selected some time ago for their low non-linear and linear distortion.

Or this from the minutes of the IEEE G-2.1 Audio Video Committee?

http://grouper.ieee.org/groups/videodist/214m9905.html

- Measurement of linear waveform distortion of analog video signal (IEEE standard 511) using 2T pulse and bar test signal. A special note has been added to the existing standard document stating that the accuracy of any linear distortion measurement is often affected by the presence of non-linear distortions which are difficult or impossible to separate from the measurement.

Or from the Deutsche Welle Radio Training Center, Quality Parameters of Audio Signals?

http://www.dwelle.de/rtc/infotheque/qual_parameter/qualpar_04.html

Precisely we should name it "non-linear distortion", to distinguish it from the linear distortion, but simply distortion is commonly used.

Or from a piece written for PBI Media's broadband group by Tom Williams of Holtzman, Inc, a company specializing in advanced digital transmittion technology?

http://www.broadband-pbimedia.com/ct/archives/1103/1103_upstreamdata.html

Linear distortions are problems that are created by a signal being subjected to a channel with either non-flat amplitude response, or bent-line phase response, or both. Linear distortions include impairments such as group delay, discrete echoes (e.g. reflections, ghosts or multipath distortion), micro-reflections and amplitude tilt. Two linear impairments—group delay and micro-reflections—can cause serious damage to upstream data, and most commonly used sweep test equipment does not measure these impairments. Understanding frequency response can help you conquer linear distortions.

Or from this page which I dunno, has a lot of Italian on it.

http://www.mclink.it/personal/MC0004/messaggi.htm

Harmonic Distortion is a means for measuring Nonlinear Distortion . Nonlinear Distortion is a form of signal processing error that creates signals at frequencies that are not necessarily present in the input. It contrasts with Linear Distortion, which is a form of error that creates no new frequencies beyond those that are present in the input signal. Linear Distortion changes the relationship of the size and timing of the frequencies that compose the input signal. Linear and Nonlinear distortion are directly based on frequencies present in the input signal.

Or this lab sheet for a class by Dr. Glenn K. Heitman, Lecturer
Electrical and Computer Engineering University of Florida?

http://www.heitman.ece.ufl.edu/4514l/manual/lab3.pdf

OBJETIVE

To measure the frequency response of a linear filter and to investigate linear and nonlinear distortion.

Or this from the Dilettante's Dictionary ("Audio terminology in these digital days")?

http://www.dilettantesdictionary.com/index.php?start=51&let=l

linear distortion : Any type of distortion that a linear system is capable of producing, as opposed to nonlinear distortion. Some types of linear distortion are frequency response errors and time-delay errors such as phase-shift.

Or this from the New Stereo Soundbook by Ron Streicher and F. Alton Everest (the latter also authored The Master Handbook of Acoustics)?

http://www.stereosoundbook.com/chapter4.htm

Distortion can take two forms: linear or non-linear. Linear distortion simply produces changes in the amplitude and phase response of the audio signal, but without adding anything else to it. Non-linear distortion, however, creates new, unwanted components and adds them to the audio signal. These components can be either harmonically or non-harmonically related to the original signal, and are quite audible even at relatively low levels compared to the original signal. Thus, non-linear distortion is generally considered much more annoying to the listener than linear distortion.

There ya go, Fred. Now you've heard of linear distortion in reference to electronics.

No need to thank me. You're quite welcome.

se

 

[HDTVman]

I see that John Curl has been back. John do you care to answer my question? When was the last time your ST1700b went back for caliberation and performance certifcation? This is a very key point.

As for the linear and nonlinear distortion question. As near as I can discover in general terms, Linear distortion is caused by passive components, Nonlinear distortion is caused by active components. Now I would include a diode as an active components.

The point is that unless we know that the test equipment is working properly how do we know what causes the result you get. Blind faith in an old piece of gear is dangerous John.

Later BZ

 

[Steve Eddy]

If we call anything that alters the signal distorsion, then also
noise is a kind of distorsion, or did you tacitly assume that
the altered signal must at least be a function of the input signal?

Hmmmm. I'd tend to not consider noise a signal distortion as it's rather an independent element. Even though it adds to the signal, it doesn't actually alter the signal itself whereas distortion is the result of an alteration of the signal itself.

se

 

[Steve Eddy]

As for the linear and nonlinear distortion question. As near as I can discover in general terms, Linear distortion is caused by passive components, Nonlinear distortion is caused by active components. Now I would include a diode as an active components.

What about an inductor with a saturable core? Would you consider that a passive component? Or how 'bout ceramic capacitors made with ferroelectric ceramics?

se

 

[Steve Eddy]

By the way, aren't we rather putting the cart in front of the horse going on speculating about possible mechanisms for distortion in wire and cable when we haven't even established yet that wire and cables even produce any distortion?

se

 

[Steve Eddy]

I see that John Curl has been back. John do you care to answer my question?

Be patient. I'm still waiting for him to answer me and tell me if he's going to accept or decline my offer to send him a dulicate set of cables that will also be sent to Bruno so that we can properly address the issue that John keeps bringing up that Bruno didn't measure the same cables he did.

Well, John?

se

 

[HDTVman]

Yes Steve, those are special cases and can cause nonlinear distortions. I qualified my statment with "in general". That doesn't include special cases. Those devices are designed to have nonlinear performance. That's why they are special cases.

LaterBZ

 

[Steve Eddy]

Yes Steve, those are special cases and can cause nonlinear distortions. I qualified my statment with "in general". That doesn't include special cases. Those devices are designed to have nonlinear performance. That's why they are special cases.

Hehehe. Ok, how 'bout audio transformers? Are they designed to have nonlinear performance? Or are they special cases too?

se