I'm not claiming that I can hear 100kHz. But audio technology is far from prefect, it still improve. I am claiming that I can hear the different but I do not know why it is different. May be it is the slew rate. We can study in this thread if slew rate influence the amp working, rather than known to its relation of power bandwidth.
In the previous of this thread I asking when we made all specifications of two amp is identical except slew rate, can we hear the different?
I was made tone control with NE5532, but I feel it sound strange. But no body can hear this abnormal sound except me at that time. And then I bring my oscilloscope and find small oscillation around 120kHz. I put small cap in feedback circuit and the oscillation was gone. I am feeling happy 😀.
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My point was that Waly provided a schematic, sufficient to check if the claims are true or not, all you have to do is enter it into LTSpice.
Not as convenient as if Waly does the work, but totally different from an unsubstantiated claim like "I can hear a difference with an Zillion V / usec slew rate".
Should be educational because my initial idea is that Edmond is correct and Waly's circuit does not handle CCS noise as neatly.
True? and if so then does it make a practical difference?
If this is well known for RF then I should improve my education in that area.
Do you have any references for this condition, preferably with a derivation?
Best wishes
David
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I don't remember somebody had pretended this in this thread.
Very different than to say: "Try do design-it as faster as you can". Exactly like "Try to get as low distortion as you can.".
Now, when we are at making compromises between the two, only careful listening can help-us.
Numbers (if reasonably low) are interesting only as they reflect the health of a build. And ensure only you have a correct amplifier. It is half of the work. The other one is: "Tune-it for it sounds good".
This involve components choice, board and cabling design and a lot of other factors, power supplies, Ac noises filtering, cables, speakers etc...
Mathematics are a tool. Simulations don't say much. There is no way you can buy the best amplifier, referring to distortion or slew rate numbers. At the end, you have to listen to figure out.
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There are no emitter resistor I ever seen in bjt RF amplifier (they usually classC), the one exist is Rbe for beter withstand. The others are inductors and caps.
Rather than claiming 1V/us/Vpk is enough, 0,001% THD is enough, etc, why do we not push all specifications further? Why do we limit our self?
We study electronics (and some of you are master of electronics) and do not pretend that we are master of biology and understand exactly how humans ears (and brain) work.
We study electronics (and some of you are master of electronics) and do not pretend that we are master of biology and understand exactly how humans ears (and brain) work.
The only reason I see to go for these impressive figures is for the "fudge"
factor.
The board layout , questionable components and the hand of the
DIY'er will degrade (slightly to massively), any good design.
If the end result is under 100ppm , we are on par with upper "mid-fi".
We DO use better components and our bare hands in construction ...
The end result should be better than what a profit driven corporation
can sucker us into buying. (Both SQ and reliability.)
OS
factor.
The board layout , questionable components and the hand of the
DIY'er will degrade (slightly to massively), any good design.
If the end result is under 100ppm , we are on par with upper "mid-fi".
We DO use better components and our bare hands in construction ...
The end result should be better than what a profit driven corporation
can sucker us into buying. (Both SQ and reliability.)
OS
But, used wisely, they can tell you a great deal about where a design is sensitive to subtle variations in parameters, and parasitics - they can guide as to exactly where one needs to be anal about implementation ...
Even to listen is not easy to figure it out.
When we listen, we listen through speakers. So, how can we be sure it is the amp sound or amp-speaker sound? As speaker is the weakest link, and amp sound quality cannot be heard without speaker, it is necessary to have a "standard" with speakers, before we can set "standard" with amplifiers, sound wise.
Look at the owners of billion dollar speakers, do they have one word for the best speaker? No. How will they know the best one if they have no idea of what should make up a good one? When they hear bad sound from the speaker, how can they know the cause of what they hear? It could be just uncontrolled room mode, bad recording, anything unrelated with the intrinsic quality of the speaker.
I for one, have a firm opinion of a correct/good speaker, regardless of price (as long as not budget design). Such speaker usually work well with almost any amplifiers, even the cheap ones (assuming current requirement and delivery is not an issue). This behavior then is beneficial to determine the best amplifier because it is independent of amp-speaker "matching". But the main idea is that we have a consistent idea/criteria regarding good/proper sound, when we select the speakers or when we select the amplifiers (or both, by listening).
I have to admit that most of my listening to amplifiers are not through transparent speakers. That's why I have never tried to say that this amp is better than that amp, because I know that there's possibility it may turn upside down when I use transparent speaker. But now I'm building a speaker protector, in order that I can use my transparent speaker to judge amplifier quality.
This issue IMO is critical. Who knows, low distortion class-d amps can sound the best through this speaker?? But of course, the first problem to solve is to define the transparent speaker (because all speakers are claimed to be transparent).
A way around that is to hook up a 220-330R quality resistor and
listen to the driver stage with headphones.
A quality IPS/VAS will sound fantastic , and ... you know it will work
with the final OPS components.
PS - You will be listening in class A , as well !
OS
listen to the driver stage with headphones.
A quality IPS/VAS will sound fantastic , and ... you know it will work
with the final OPS components.
PS - You will be listening in class A , as well !
OS
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Good news for you is, nobody understand how brain works, including experts in neurology. So you have a chance to speculate. After all, people use brain to study brain. What needed is actually a little of reading and a lot of brain.
I still cannot fully accept the idea of listening the I/s alone, except just to know the general quality of certain topology. Amplifier quality has to be heard as a whole with the output stage.
Even after bypassing a power amplifier, I found most headphone is not good enough. I don't know about Stax headphone, but I haven't heard headphone around $300 price range that is more "transparent" than my speaker.
Good question.
First, i use speakers with a 6 Ohm flat impedance between DC and 50Khz to ensure there is no charge problem. And make sure no oscillation or over-shoot on little square waves once plugged.
Concerning speaker's sound itself, you are supposed to be familiar to the one we use. And i believe our ears able to discriminate the amplifier's distortions/blurr from the speaker's ones.
A little like our eyes are able to compensate light temperature.
Of course, if your speakers are not able to reproduce details and dynamic good enough, you will not hear differences on those aspects.
Last, it is a 'comparing' work, not an 'absolute' judgment.
One thing is for sure, if you can hear little details (sounding natural) with one amp that you cannot with an other, there is a big chance the first one is better ;-)
Same thing with all other subtle and important aspects, like separation between instruments, Depth and width of the sound stage, ease to localize in space, presence etc.
One thing is a good test, when the singer had recorded twice the same voice, both in the center. Did-you hear the two voices, well separated, or 'a doubled voice sound' ?
One a Piano, can-you hear the pedals noises, the hit of the hammer on the chords ?
One an electric guitar, the difference between mediator and fingers ? Feel the gauges of the chords ?
On drums, feel the hit of the sticks ? etc.
In a recording studio, how often you need to use the solo track's buttons ?
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Esperado said:
What I mean is, there is a possibility that with speaker 1, amp A is better (eg more detailed) than amp B, but when speaker 2 is used, amp B is better.
It is also good to have a "criteria", such as "detail" in your case. Not everyone use the same criteria especially those with low end speakers.
But "detail" is a fine criteria. A better one is "accurate" (you use "natural" wording). If you can hear a rat running on the stage, that's "detail" (mostly related to expensive speakers). "Accurate" is it has to sound "natural" or as recorded. If this is agreed, problem not yet solved, because accuracy not as simple as it seems.
As a gross, gross, oversimplification ... "detail" comes from the speakers, "accurate" comes from the amplifier ...
That's too gross, Frank, but I could agree. It is a problem when the speaker is not accurate and you want to hear amplifier accuracy.
Lately I tried to build a very small speaker (2"). I was surprised that I couldn't recognize the singer (local singer, Bunga Citra Lestari) of a song. Other singers were fine. That's how detrimental a crossover can be to accuracy, without being recognized by the majority of listeners. That's why most top loudspeakers are 2nd order at most. Only the best can come up with complex crossovers.
Hi Bob ,
This subject is redundant and not by chance since this is about
the single parameter where thoses wrongly called CFAs have
a slight advantage over usual VFAs if the latters are designed
with relatively high NFB network impedance and slow input
transistors.
Moreover there s a confusion that seems to arise from the necessary
conditions to yield low distorsion at high frequencies when using a two
stage topology , that is , one has to increase NFB at high frequencies and this will inevitably increase the slew rate given the increased ULGF , hence the flawed belief that speed equal linearity and that thoses two parameters are somewhat dependant.
As you rightly point it there s other parameters to focus on since
slew rate , contrary to linearity, is not a parameter whose variation
is linearly perceived as once the minimal value is reached the by products
of a too low SR , IMD, collapse exponentialy or so and are no more the cause
of the remaining distorsions that have their source in an insufficent linearity
of the different stages.
Hearing is the limiting factor in the musical chain , that s a given,
otherwise we wouldnt need anything else than a multimeter
as instrumentation..
Once and for all , a musical signal that make a 20V/us amp slew at 2V/us
will also force a 2000V/us amp to slew at 2V/us and if the max SR induced
by this signal is 3V/us how could one make a difference between the two
amps since their outputs are slewing at exactly the same rate..???..
Simulations are applied mathematics and it is happy because
if we had to manualy compute our sims experiments i guess
that it would take years to check even a basic circuit if the
same precision as a simulator is required...
I tried Edmond's diamond, it doesn't need as high as current like Wally said, just keep them in conductive (classA).
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Provided the amps slew rates are enough there wont be any difference
since their outputs will slew at the same rate so there s actualy no
difference to be heard.
That would never happen, two amps everything identical except slewrates.
@ jay
Probably that BCL voice recorded at her menstrual cycle, so your ears simply reject it.😀