Slew, Tone and Bullard Laws of Harmonics - is there a link?
I want to try out the following sequence of arguments on readers
to see if it makes sense and has legs.
1. Low slew rate CD player op amps have a wider output to input
time delays compared to high slew op amp/players.
2. These time delays add error odd-harmonics not present in the original signal according to https://www.linkedin.com/pulse/slew-rate-harmonics-dan-bullard Bullard Laws of Harmonics. The harmonic errors are defined by the slew rate value.WRONG question: the right one is "is there a relation between "high slew rate" opamps and "more tone"?
3. these time-related added odd-harmonic error differences result "partly" in the differences in what is heard between op amps with different slew values.
4. The greater odd harmonics of low slew op amps adds an edge and a cleaner sound to CD replay or call it less tone-full. High slew op amps will have less odd harmonics and sound less edgy and less clean and will be perceived as having more tone.
I suppose i wanted to find a reason why high slew op amps are
associated with more tone.
do the sequence of arguments work? or am i barking up the wrong tree.
On Monday, October 17, 2022 at 12:34:08 PM UTC-4, oben...@gmail.com wrote:
On 10/17/2022 5:30 AM, oben...@gmail.com wrote:
Slew, Tone and Bullard Laws of Harmonics - is there a link?
I want to try out the following sequence of arguments on readers
to see if it makes sense and has legs.
1. Low slew rate CD player op amps have a wider output to inputWho cares about the delay? Why is this important?
time delays compared to high slew op amp/players.
2. These time delays add error odd-harmonics not present in the original signal according to https://www.linkedin.com/pulse/slew-rate-harmonics-dan-bullard Bullard Laws of Harmonics. The harmonic errors are defined by the slew rate value.
3. these time-related added odd-harmonic error differences result "partly" in the differences in what is heard between op amps with different slew values.
4. The greater odd harmonics of low slew op amps adds an edge and a cleaner sound to CD replay or call it less tone-full. High slew op amps will have less odd harmonics and sound less edgy and less clean and will be perceived as having more tone.
I suppose i wanted to find a reason why high slew op amps areWRONG question: the right one is "is there a relation between "high slew rate"
associated with more tone.
opamps and "more tone"?
And even THAT question is flawed because you've presented NO agreed upon definition of "more tone" or even that such a definition exists.
Nor have you presented any relevant definition of "high slew rate" that's relevant in this context.
Let's, indeed, look at what IS relevant. Assume the bandwidth of the CD player is 22 kHz. And let's further assume that the maximum output voltage is 2V RMS or 2.8V Peak.
As
SR = 2 pi f Apk
where SR is slew rate in v/s, f is frequency and Apk is the peak amplitude, from the above assumptions, the slew rate is:
SR = 2 pi 22000 Hz 2.8 V
SR ~= 387000 V/s
or, in more common notation, .387 uV/s
Now, I ask you to make one more assumption: let's assume we're simply talking about
a signal from ANY source, not a CD player, but ANY source, like a precision laboratory
pulse generate on which you can arbitrarily set amplitude and slew rate. HP made a
bunch of them.
Now, with this last assumption in mind, it makes NO difference whether we're talking
about the output from a pulse generator or a lightning bolt hitting your cable
or your CD player or your phone preamp: a signal bandwidth of 22kHz swinging 2.8 volts
peak will have a slew rate of .387 uV/s.
Now, what might be an example of a "slow" slew rate amplifier in this context?
Well, let's go back a few years, perhaps, like 54 years at the introduction of the 741
opamp by Fairchild. It had a slewrate spec of 0.5 V/us. That's 30% faster than is required.
But let's call that one "marginal".
How about a TL081? For that, we only have to go back 45 years for that one. And it has
a slew rate of 13 V/us.
So far, we're still at least 7 years befoe the commercial intruduction of CD players.
In 1982 (40 years ago), Harris introduced the HP-2539 with a slew rate of 600
V/us.
Okay, enough of the history lecture, let's ask a question more relevant to the
topic at hand:
Are there ANY CD players on the market within the last, oh 35 years that have opamps in the audio signal path with slew rate under 0.5 V/uS? How about less than 13 V/us.
If the answer is NONE, than I believe your entire thesis was born devoid of legs.
do the sequence of arguments work? or am i barking up the wrong tree.Assuming you were dragged to the tree (y'know, that leg part alluded
to above), most assuredly, you are.
--
Dick Pierce
Diverse Pursuits
Technical Engineering/Development
cartchunk.org
Boston - Spruce Head
Thanks for this. i see what you mean about "more tone" question and stating the slew value. Re time delays: These time delays add error odd-harmonics not present in the original signal according to https://www.linkedin.com/pulse/slew-rate-harmonics-dan-bullard Bullard Laws of Harmonics. The harmonic errors are defined by the slew rate value.
dan-bullard Bullard Laws of Harmonics. The harmonic errors are defined by the slew rate value.Thanks for this. i see what you mean about "more tone" question and stating the slew value. Re time delays: These time delays add error odd-harmonics not present in the original signal according to https://www.linkedin.com/pulse/slew-rate-harmonics-
What Dick gave the science for, and what I am suggesting:
Can *you* hear it?
Does it affect *your* enjoyment of what you hear?
That windmill is calling!
Peter Wieck
Melrose Park, PA
You are a true knight in search of a windmill. I suggest you stop 'reading' and start listening. When you find a complete system that appeals to your ears irrespective of what it might include, go with that for a while - several weeks at least. If andwhen it continues to appeal to your ears *STOP THERE" and make it your baseline. Give it a few months.
And:
THEN: start experimenting with that system, element by element as your curiosity and wallet permit. That which does nothing - let it be. That which improves its appeal (after that minimum of a few weeks) keep. That which causes a negative reaction -much more likely to be immediate than not - delete.
CD players - every one of them from that $19 Chinese knock-off to the outrageously costly Moon pull from the same universe of chipsets. Where they differ would be in in the transport, and in the analog output chain. And, as with any other mechanical oranalog device, there is but so much that can be done to solve an entirely basic audio requirement. After which smoke, mirrors and yiches are the drivers. Once upon a time, a part-time used car salesperson (and a very successful one) let me in on his
Peter Wieck
Melrose Park, PA
Please let us know what your system includes at this time. And, in all seriousness, and taking you directly at your word, what sort of specific problems are you experiencing such that you feel that you "....can't hear instruments because of the noiseor if piano reproduction sounds more like a harpsichord or sounds thin and washed out...." ?
That does seem to indicate severe issues with your system, so knowing what the system includes may be helpful in diagnosing those issues and making suggestions for improvement. I am sitting in my office with my 70 year-old ears listening to baroqueharpsichord through a simple vintage system, the newest part of which was made in 1994 (Sony CD changer) and the oldest part in 1963 (Dynaco ST35). I discern no noise, and certainly the harpsichord sounds substantially different from the piano (Mozart)
I would posit that what you are experiencing is much more specific that op-amp speed or your particular CD player.cleaned and the laser focus checked. No more.
https://cdn.shopify.com/s/files/1/1683/2705/products/Sony-CDP-C215-5-Disc-CD-Player-Changer-Pulse-DA-Converter-Electronics_cfa468a9-2075-4f2b-8945-364a4159662b_750x750.jpg?v=1631614621
http://diyaudioprojects.com/Schematics/images/Dynaco-ST35-Tube-Amplifier-Kit-cage.jpg
http://cdn.shopify.com/s/files/1/0478/4884/9576/products/Dynaco-PAS3X-TubePreamp-FrontRight_1024x.jpg?v=1616770343
https://assets.catawiki.nl/assets/2018/3/28/6/b/3/6b3f34ba-090b-4bfc-886f-88b22fb4ea28.jpg
The Dynaco products have the enhanced power-supplies installed and adjustable bias has been added to the 35 (EFB in both cases). The speakers are as-found, but I have verified that the woofer does not suffer from surround rot. The CD changer has been
My point is that there is not a single exotic piece in the system, and to my ears, it does quite well in this environment. As well as providing a source of amusement to colleagues, clients, contractors and vendors passing through.
Peter Wieck
Melrose Park, PA
What I find interesting is that you really don't necessarily need good electronics to like music.
What I find interesting is that you really don't necessarily need good electronics to like music.
For example, I have my grandparent's RCA Model 224 console radio, AM and shortwave. I stream period music to it using a Bluetooth AM transmitter and 40s Junction on SiriusXM.
Modern music sounds like crap... but older music? The elaborate tone filtering makes the old stuff sound really nice.
My other grandfather's Victrola sounds pretty nice too, of course the reproducer had to be rebuilt, but the thing is a hundred years old!
I do not doubt that in some instances a faster slew rate op amp might sound better... but I wouldn't necessarily shotgun replace them, either.
I've gotten instant improvements by cleaning the interconnects. If you're not doing that at least once a year, what's the point of changing op amps?
Tom
Slew, Tone and Bullard Laws of Harmonics - is there a link?noise will increase tone but others might say that colouration distortion can add to tone. Tone is a pretty nebulous concept anyway but it is an audio attribute we strive for. Bullard Laws link odd harmonics to slew value. What we are hearing is
I want to try out the following sequence of arguments on readers to see if it makes sense and has legs.
1. Low slew rate CD player op amps have a wider output to input time delays compared to high slew op amp/players.
2. These time delays add error odd-harmonics not present in the original signal according to https://www.linkedin.com/pulse/slew-rate-harmonics-dan-bullard Bullard Laws of Harmonics. The harmonic errors are defined by the slew rate value.
3. these time-related added odd-harmonic error differences result "partly" in the differences in what is heard between op amps with different slew values.
4. The greater odd harmonics of low slew op amps adds an edge and a cleaner sound to CD replay or call it less tone-full. High slew op amps will have less odd harmonics and sound less edgy and less clean and will be perceived as having more tone.
I suppose i wanted to find a reason why high slew op amps are associated with more tone. And from my reading of Bullard Laws of Harminics, this seems to unlock some of this question. Op amp tone is clearly a function of a number of things. Lower op amp
do the sequence of arguments work? or am i barking up the wrong tree.Thanks for the replies.
If i can't hear instruments because of the noise or if piano reproduction sounds more
like a harpsichord or sounds thin and washed out then i want to know why and what i
have to do to improve my listening experience.
By whom? Under what conditions and prejudices? For what reasons?
Also glad RDP is still with us.
i totally agree with Dicks science. low slew players don't lack pace. my original post is not about op amp speed.
1. Low slew rate CD player op amps have a wider output to input time delays compared
to high slew op amp/players.
...
3. these time-related added odd-harmonic error differences result "partly" in the differences
in what is heard between op amps with different slew values.
4. The greater odd harmonics of low slew op amps adds an edge and a cleaner sound to CD
replay or call it less tone-full. High slew op amps will have less odd harmonics and sound
less edgy and less clean and will be perceived as having more tone.
I suppose i wanted to find a reason why high slew op amps are associated with more tone.
On Tuesday, October 18, 2022 at 10:28:38 AM UTC-4, oben...@gmail.com wrote:thanks for your response
i totally agree with Dicks science. low slew players don't lack pace. my original post is not about op amp speed.I'm sorry, but your original post WAS about op amp speed. Here are some quotes from YOUR
posts in this threead:
From your first post on Oct17:
1. Low slew rate CD player op amps have a wider output to input time delays comparedNow, just in this partial quote from YOUR post, "op-amp" and "slew" is mention in direct context
to high slew op amp/players.
...
3. these time-related added odd-harmonic error differences result "partly" in the differences
in what is heard between op amps with different slew values.
4. The greater odd harmonics of low slew op amps adds an edge and a cleaner sound to CD
replay or call it less tone-full. High slew op amps will have less odd harmonics and sound
less edgy and less clean and will be perceived as having more tone.
I suppose i wanted to find a reason why high slew op amps are associated with more tone.
6 times.
But, then you say: "my original post is not about op amp speed".
which is it?
On Wednesday, October 19, 2022 at 8:23:04 PM UTC+1, Dick Pierce wrote:
On Tuesday, October 18, 2022 at 10:28:38 AM UTC-4, oben...@gmail.com wrote:
i totally agree with Dicks science. low slew players don't lack pace. my original post is not about op amp speed.I'm sorry, but your original post WAS about op amp speed. Here are some quotes from YOUR
posts in this threead:
From your first post on Oct17:
1. Low slew rate CD player op amps have a wider output to input time delays comparedNow, just in this partial quote from YOUR post, "op-amp" and "slew" is mention in direct context
to high slew op amp/players.
...
3. these time-related added odd-harmonic error differences result "partly" in the differences
in what is heard between op amps with different slew values.
4. The greater odd harmonics of low slew op amps adds an edge and a cleaner sound to CD
replay or call it less tone-full. High slew op amps will have less odd harmonics and sound
less edgy and less clean and will be perceived as having more tone.
I suppose i wanted to find a reason why high slew op amps are associated with more tone.
6 times.
But, then you say: "my original post is not about op amp speed".
which is it?thanks for your response
1. Low slew rate CD player op amps have a wider output to input time delays compared
to high slew op amp/players.
2. These time delays add error odd-harmonics not present in the original signal according to
https://www.linkedin.com/pulse/slew-rate-harmonics-dan-bullard Bullard Laws of
Harmonics. The harmonic errors are defined by the slew rate value.
[ rare insert from the mod: if you are asked a direct question and you
avoid answering it, I am inclined to think you are trying to troll.
-- dsr the last remaining moderator ]
On Wednesday, October 19, 2022 at 8:23:04 PM UTC+1, Dick Pierce wrote:
On Tuesday, October 18, 2022 at 10:28:38 AM UTC-4, oben...@gmail.com wrote:
i totally agree with Dicks science. low slew players don't lack pace. my original post is not about op amp speed.I'm sorry, but your original post WAS about op amp speed. Here are some quotes from YOUR
posts in this threead:
From your first post on Oct17:
1. Low slew rate CD player op amps have a wider output to input time delays comparedNow, just in this partial quote from YOUR post, "op-amp" and "slew" is mention in direct context
to high slew op amp/players.
...
3. these time-related added odd-harmonic error differences result "partly" in the differences
in what is heard between op amps with different slew values.
4. The greater odd harmonics of low slew op amps adds an edge and a cleaner sound to CD
replay or call it less tone-full. High slew op amps will have less odd harmonics and sound
less edgy and less clean and will be perceived as having more tone.
I suppose i wanted to find a reason why high slew op amps are associated with more tone.
6 times.
But, then you say: "my original post is not about op amp speed".
which is it?thanks for your response
1. Low slew rate CD player op amps have a wider output to input time delays compared to high slew op amp/players.
2. These time delays add error odd-harmonics not present in the original signal according to https://www.linkedin.com/pulse/slew-rate-harmonics-dan-bullard Bullard Laws of Harmonics. The harmonic errors are defined by the slew rate value.
the linkedin link gives more info.
[ rare insert from the mod: if you are asked a direct question and you
avoid answering it, I am inclined to think you are trying to troll.
-- dsr the last remaining moderator ]
On Wednesday, October 19, 2022 at 8:23:04 PM UTC+1, Dick Pierce wrote:
On Tuesday, October 18, 2022 at 10:28:38 AM UTC-4, oben...@gmail.com wrote:
i totally agree with Dicks science. low slew players don't lack pace. my original post is not about op amp speed.I'm sorry, but your original post WAS about op amp speed. Here are some quotes from YOUR
posts in this threead:
From your first post on Oct17:
1. Low slew rate CD player op amps have a wider output to input time delays comparedNow, just in this partial quote from YOUR post, "op-amp" and "slew" is mention in direct context
to high slew op amp/players.
...
3. these time-related added odd-harmonic error differences result "partly" in the differences
in what is heard between op amps with different slew values.
4. The greater odd harmonics of low slew op amps adds an edge and a cleaner sound to CD
replay or call it less tone-full. High slew op amps will have less odd harmonics and sound
less edgy and less clean and will be perceived as having more tone.
I suppose i wanted to find a reason why high slew op amps are associated with more tone.
6 times.
But, then you say: "my original post is not about op amp speed".
which is it?thanks for your response
1. Low slew rate CD player op amps have a wider output to input time delays compared to high slew op amp/players.
2. These time delays add error odd-harmonics not present in the original signal according to https://www.linkedin.com/pulse/slew-rate-harmonics-dan-bullard Bullard Laws of Harmonics. The harmonic errors are defined by the slew rate value.
the linkedin link gives more info.
[ rare insert from the mod: if you are asked a direct question and you
avoid answering it, I am inclined to think you are trying to troll.
-- dsr the last remaining moderator ]
On Wednesday, October 19, 2022 at 4:03:27 PM UTC-4, oben...@gmail.com wrote:
On Wednesday, October 19, 2022 at 8:23:04 PM UTC+1, Dick Pierce wrote:
On Tuesday, October 18, 2022 at 10:28:38 AM UTC-4, oben...@gmail.com wrote:
i totally agree with Dicks science. low slew players don't lack pace. my original post is not about op amp speed.I'm sorry, but your original post WAS about op amp speed. Here are some quotes from YOUR
posts in this threead:
From your first post on Oct17:
1. Low slew rate CD player op amps have a wider output to input time delays comparedNow, just in this partial quote from YOUR post, "op-amp" and "slew" is mention in direct context
to high slew op amp/players.
...
3. these time-related added odd-harmonic error differences result "partly" in the differences
in what is heard between op amps with different slew values.
4. The greater odd harmonics of low slew op amps adds an edge and a cleaner sound to CD
replay or call it less tone-full. High slew op amps will have less odd harmonics and sound
less edgy and less clean and will be perceived as having more tone.
I suppose i wanted to find a reason why high slew op amps are associated with more tone.
6 times.
But, then you say: "my original post is not about op amp speed".
Okay, I just took the opportunity to read this "Dan Bullard's Law of Harmonics."which is it?thanks for your response
1. Low slew rate CD player op amps have a wider output to input time delays compared
to high slew op amp/players.
2. These time delays add error odd-harmonics not present in the original signal according to
https://www.linkedin.com/pulse/slew-rate-harmonics-dan-bullard Bullard Laws of
Harmonics. The harmonic errors are defined by the slew rate value.
Several comments:
1. Unlike someone like Isaac Newton, Dan Bullard has neither the stature nor acceptance nor technical and scientific underpinnings (at least in his article
get to call what he writes as a Law of Anything.
2. I have no idea what Bullard does for a living, but it's clear that he suffers
from a fundamental misunderstanding of the topic.
For example, he claims:
"Look at that! Odd harmonics galore! Why? most people believe that harmonics come from discontinuities in voltage, in fact, discontinuities can be created by
discontinuites in time too."
I'm sorry, but this is so much BS and gobbledygook.
I can create harmonic distortion simply by LINEARLY summing the right collection
of completely LINEAR sine functions. Indeed, I can duplicate Bullards sample slew-limited waveform PRECISELY this way. And not one of those sine functions is slew-limited. I say so, Fourier says so.
Further, if you have a signal who's first derivative wrt time is non-zero (i.e. it changes
from moment to moment, a discontinuity in time MUST cause a discontinuity in amplitude. Bullard cannot arbitrarily treat time and amplitude as independent phenomenon.
3. He states:
"while most people believe..."
You want to risk life and limb by waving that red flag in front of me, do so at your
at your own peril. How on earth do you know what "most people believe?" Statements
like this are the height of high-end audio ignorance and BS.
4. He states:
"this is exactly why we don't have people looking at o'scopes to verify waveform quality"
Really? Is he kidding? I stopped using an oscilloscope for such probably 50+ years ago.
How many people in the real world actually do this?
5. He states:
"the invention of the FFT by Cooley and Tukey is such a watershed event in human history.
It allows us to deduce signal quality very, very quickly (hence the name FAST Fourier
Transform).
This stands out like a sore thumb set on fire then doused with radium in an attempt
to smother the flames.
The Cooley/Tukey alorithm is but one of amny mathematically equivalent transforms
that are computationally efficient in one way or another.
It is NOT "very very" quicker per say, it is computationally efficient ONLY WHEN THE
THE DATA SET IS EXACTLY A POWER OF TWO SAMPLES LONG (more on this below). And, come on, it's a "watershed event in human history". Really? as significant as say,
Newton's law of gravity? Einstein's theory of general relativity (which under relativistic
situation, where Neton falls apart, bive FAR more accurate results)? Quantum mechanics
(which, after all, does allow us to have this exchange)? Penicillin? Calculus? The internet?
6. He states:
"the Even harmonics (red) are likely due to the fact that my poor sine wave gets one cycle
to run through the "filter" of my slew rate restriction."
Sorry, no. It is as likely due to the the distinct possibly that even though the number of
points passed to the FFT is, indeed, 2018 samples long, the entire waveform does not
complete in it's entirety in that 2048 second. In other words, you're looking at the
discontinuity at the end of the data. In yet other words, you may well have failed
to obey your own rules about ttime discontinuities. Had you roperly windows the data,
those harmonics wouldn't be there. The error thus is not the "filter" whatever that means,
but sloppy technique.
"The DC offset (bin zero) is a clue t what is going on."
It is indeed: it screams "bad, sloppy technique" to me: if my hypotheses above is correct,
the resulting waveform he generated MUST have an offset because the date set does not
integrate to 0 within the FFT bin size.
7. Lastly, his claims suffer the same problem as Obe...s original post: it utterly fails to address
his claims in the light if ACTUAL real-world data. Though it is difficult to read the actual
scale of his graphs, he claims he simulated a slew rate of, to quote him, "6V/ms."
Does he REALLY mean 6V/mS? If so, that mean 0.006 V/us and in all of my career, I have
NEVER ONCE encoutered such a preposterously slow slew rate (unless done deliberately as
an opamp based integrator.
The excercise I did earler whowed clearly that you meed a minimum of
an opamp with a minimum slew-rate spec of 0.387 V/us. That's 387 V/ms,
using Bullard's odd notation. If course, if you could ever hope to find such a demonstrably lousy part and it could fit, the CD player would sound like sh*t.
But we can't, we won't, and Bullard's law is a load of crap.
So there.
[ rare insert from the mod: if you are asked a direct question and you avoid answering it, I am inclined to think you are trying to troll.Yeah, you're probably right. But the bait was too large, too juicy and too attractive
-- dsr the last remaining moderator ]
to ignore.
--
Dick Pierce
Diverse Pursuits
Technical Engineering/Development
cartchunk.org
Boston - Spruce Head
As i understand it Dan Bullard is using the term slew as a measure of errors. and not as a measure of speed. Dan Bullard outlines his position in the link given.
it was not my intention to cause offence and i apologise if i have offended Dick or anyone else.
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