andy_c said:
There are no dumb questions, only dumb answers
Something that probably a simulator won't catch. When the protection kicks in (first cutting the buffer current then the VAS current, to avoid transient output spikes) you end up with a configuration in which the MOSFET gates are pretty much floating; without the 220k resistors, the output may go randomly to some DC level. With the 220k resistors the output is guaranteed to stay at 0V.
forr,
Perhaps not enough emphasis. It is essentially about spectrum, not level. The harmonic spectrum should follow the ear`s distortion pattern, a basic condition of natural, transparent sound. Having this in mind, topologies favorably producing such a spectrum can be chosen. A single THD figure does not offer meaningful information, low values can be understood purely negatively, being only achievable by considerable amount of GNF, which destructively and impoverishingly transforms also vital harmonics into irritating high frequency intermodulation distortion products, causing precious detail losses.
How do you know it represented a degradation, not a correction?
This is an unfortunate misconception. The second order harmonic is a hardly detectable, benign distortion, resulting in very small intermodulation. In other words, the ear does not bother much with it.
Hi Lumba Gir,
---The harmonic spectrum should follow the ear`s distortion pattern, a basic condition of natural, transparent sound.---
This is an idea, only applying to amplifiers, made popular by Jean Hiraga. But where is the slightest scientific evidence of this ? Considering the whole chain from mikes to loudspeakers, do you think that the ideal distorsion pattern has any chance to be respected ?
Would be that idea true, every musical instrument should follow the ear's distorsion pattern, don't they ?
---How do you know it represented a degradation, not a correction?---
---This is an unfortunate misconception. The second order harmonic is a hardly detectable, benign distortion, resulting in very small intermodulation.---
Do the maths.
Any non-linearity enhances harmonic distorsion and then, necessarily, the intermodulation you are so afraid of with high feedback schemes.
---The harmonic spectrum should follow the ear`s distortion pattern, a basic condition of natural, transparent sound.---
This is an idea, only applying to amplifiers, made popular by Jean Hiraga. But where is the slightest scientific evidence of this ? Considering the whole chain from mikes to loudspeakers, do you think that the ideal distorsion pattern has any chance to be respected ?
Would be that idea true, every musical instrument should follow the ear's distorsion pattern, don't they ?
---How do you know it represented a degradation, not a correction?---
---This is an unfortunate misconception. The second order harmonic is a hardly detectable, benign distortion, resulting in very small intermodulation.---
Do the maths.
Any non-linearity enhances harmonic distorsion and then, necessarily, the intermodulation you are so afraid of with high feedback schemes.
syn08, It's interesting to see someone else is using ADA4899. How would you describe the sound of it? When I used it as headphone amp, I found it to be the "clearest" sounding amp I've ever heard. It gave the impression of "no" low order distortion at all. I've never heard voices so clear as with this chip. However, buffered or not, there was a sligth lack of weight/body. Have you managed to get a warmer tonality from it?
nelsonvandal said:
Listening tests are not going to happen before early next year, to allow finishing the construction (as usual in my projects, the signal path is only about 30% of the electronics) including case, etc...
Based on my previous experience, ADA4899-1 is one of the best bipolar opamps today, in terms of noise, distortion, bandwidth, etc... It's only drawback are the low voltage supply. It also requires mucho care in laying out, due to the very large BW it doesn't take much to turn it into a 200MHz oscillator.
forr,
Ideally, when the harmonic spectrum fully corresponds with the aural harmonic pattern, all the harmonics being suppressed by the auditory system, despite measured distortion, you would just hear fundamental tones.
Generally, the second harmonic level is too low, you would most likely prefer the sound with that increased, unless you are using linear tubes.
Closest, you get with directly heated triodes (only in single-ended mode, no GNF). Such astonishing subjective quality is not achievable with solid state, tubes are simply vastly superior. The measured data are, however, not impressive at all, i.e.THD may be several hundred times higher than that you are used to see, but it`s about spectrum, not level,right?
Another feature of hearing can be mentioned here, its masking behavior.
No, this is not an idea, but a well-founded (obviously not widely-held) knowledge, result of scientific research in hearing.
Ideally, when the harmonic spectrum fully corresponds with the aural harmonic pattern, all the harmonics being suppressed by the auditory system, despite measured distortion, you would just hear fundamental tones.
Generally, the second harmonic level is too low, you would most likely prefer the sound with that increased, unless you are using linear tubes.
Closest, you get with directly heated triodes (only in single-ended mode, no GNF). Such astonishing subjective quality is not achievable with solid state, tubes are simply vastly superior. The measured data are, however, not impressive at all, i.e.THD may be several hundred times higher than that you are used to see, but it`s about spectrum, not level,right?
Another feature of hearing can be mentioned here, its masking behavior.
Jan,
thank you for showing interest and wasting your presumably precious time. I feel deeply honored by your participation.
thank you for showing interest and wasting your presumably precious time. I feel deeply honored by your participation.
Much to my humble regret.
You could have mitigated the incorrectness of that statement by adding "as far as I know".
It`s a somewhat ungraceful formulation considering the intricacy of the subject.
Re: trolling
Lumba wants distortion .. of a certain kind & a certain level
I am trying to remember one time ever of my many setups of amplifiers,
where I had not the goal to keep THD as low as possible.
.. but can not find this in my subjective memory.
Even when trying do very simple amplifiers (very few transistors to amplify)
I do everything I can to optimize for low distortion.
By trying to find the sweet spot where each transistor within the current circulation system - the amplifying circuit,
contributes with as good transfer function as possible.
And when the transfering is as good as possible,
current in ... is proportional to ... current out, creating voltages,
we can use also other expressions for this:
- linearity
- low distortion
- high fidelity = hi-fi
--------------------------------
I am more for the 'hi-fi', than I am for pleasing sound.
'Sounds better'
is this what we are after?
Music should not sound better or worse than as when created.
This is to show respect for the Music maker + the Producer.
Say I create some Musical Artwork that is supposed to have a lot of 3rd, 5th, 7th & 9th distorrtion.
Just to create a feeling of disharmony & upset and 'attack' the listener.
Because this is what I want to express with my music piece.
It does not need to be low-fi punk garage music, for this
Nowadays there is a lot of electronically created music.
Where we can modle sound waves to almost antging disharmonic.
Now Lumba will listen with his '2nd order generators' with his aural spectrum,
and so the cords I have used with more odd order overtones contents
will be more pleasant to his ears.
If ever I have the opportunity to see Mona-Lisa by Michelangelo
I certainly want to polish my glasses,
I am not talking about sunglasses of this or that colour.
And I do not want to filter my impression using any sort of red, rosy or green glasses.
It would be One Crime against the Painter. The Composer.
Even if this would not be forbidden, to do so.
Keep up your good work Edmond
You have more important things to deal with here,
than to try to make somebody understand, that does not want to understand.
When we do not want to get things .. there are 100 of our own excuses
for not to understand what anybody will tell us.
More hi-fi!
Less distortion, Please!
Here at www.diyaudio.com
Lineup regards
Edmond Stuart said:
Lumba wants distortion .. of a certain kind & a certain level
I am trying to remember one time ever of my many setups of amplifiers,
where I had not the goal to keep THD as low as possible.
.. but can not find this in my subjective memory.
Even when trying do very simple amplifiers (very few transistors to amplify)
I do everything I can to optimize for low distortion.
By trying to find the sweet spot where each transistor within the current circulation system - the amplifying circuit,
contributes with as good transfer function as possible.
And when the transfering is as good as possible,
current in ... is proportional to ... current out, creating voltages,
we can use also other expressions for this:
- linearity
- low distortion
- high fidelity = hi-fi
--------------------------------
I am more for the 'hi-fi', than I am for pleasing sound.
'Sounds better'
is this what we are after?Music should not sound better or worse than as when created.
This is to show respect for the Music maker + the Producer.
Say I create some Musical Artwork that is supposed to have a lot of 3rd, 5th, 7th & 9th distorrtion.
Just to create a feeling of disharmony & upset and 'attack' the listener.
Because this is what I want to express with my music piece.
It does not need to be low-fi punk garage music, for this
Nowadays there is a lot of electronically created music.
Where we can modle sound waves to almost antging disharmonic.
Now Lumba will listen with his '2nd order generators' with his aural spectrum,
and so the cords I have used with more odd order overtones contents
will be more pleasant to his ears.
He will enjoy the 'good sound' maybe
and feel really happy.
While my artwork was supposed to create a feeling of dis-comfort.
Maybe even one impression of fear within the listener!
I have failed to transmit my own need of expression my state of mind to the listener.
My artwork is maybe not destroyed
but my expressed message was not perceived correctly
If ever I have the opportunity to see Mona-Lisa by Michelangelo
I certainly want to polish my glasses,
I am not talking about sunglasses of this or that colour.
And I do not want to filter my impression using any sort of red, rosy or green glasses.
It would be One Crime against the Painter. The Composer.
Even if this would not be forbidden, to do so.
Keep up your good work Edmond
You have more important things to deal with here,
than to try to make somebody understand, that does not want to understand.
When we do not want to get things .. there are 100 of our own excuses
for not to understand what anybody will tell us.
More hi-fi!
Less distortion, Please!
Here at www.diyaudio.com
Lineup
regards
Knock it off, you guys.
Accept that opinions differ, and leave it at that.
I've got some funny ideas too, but I try to walk away when passions are aroused. You are all incredibly smart, be smart emotionally......
I think the appropriate question is this:
'Why are so many audiophiles beguiled by SETs, particularly DHTs, when the measured distortion is so outrageously high?'
There just HAS to be a reason for it.
Hugh
Accept that opinions differ, and leave it at that.
I've got some funny ideas too, but I try to walk away when passions are aroused. You are all incredibly smart, be smart emotionally......
I think the appropriate question is this:
'Why are so many audiophiles beguiled by SETs, particularly DHTs, when the measured distortion is so outrageously high?'
There just HAS to be a reason for it.
Hugh
"little pot"
I didn't say that. I said: "it cannot compensate for odd harmonics"
Of course, my little pot won't help to remove disturbances, caused by other mechanisms, as that was never my intention.
So don't disprove what I have never claimed.
>I'm afraid it's much more complicated than nulling a bridge around the GNFB pickup point, to compensate for layout asymmetries (your words).
Apparently you have connected the wiper of 'my little pot' (via a resistor or so) to the GNFB pickup point. That is totally WRONG! No wonder that your 'experimental conclusions, FWIIW, were disappointing.
Opposed to your findings, my circuit works at any signal level and at any frequency.
You have a great talent to spoil my ideas by using (again!) a wrong test circuit.
syn08 said:
I didn't say that. I said: "it cannot compensate for odd harmonics"
Of course, my little pot won't help to remove disturbances, caused by other mechanisms, as that was never my intention.
So don't disprove what I have never claimed.
>I'm afraid it's much more complicated than nulling a bridge around the GNFB pickup point, to compensate for layout asymmetries (your words).
Apparently you have connected the wiper of 'my little pot' (via a resistor or so) to the GNFB pickup point. That is totally WRONG! No wonder that your 'experimental conclusions, FWIIW, were disappointing.
Opposed to your findings, my circuit works at any signal level and at any frequency.
You have a great talent to spoil my ideas by using (again!) a wrong test circuit.
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