Yes I know it is the EM field induction into the PCB tracks/parts causing extra distortions, so the case layout will be checked entirely by THD measurements to find the best wires plus SMPS positions inside. The info is good just to know where are we at ppm THD levels, practically anything not properly done (PCB layout for example etc.) can cause higher THD.
Exactly, I suggest to use trimm-caps since that's the best way to find compensation's sweet-spot.
Hehe
Well, it require some 'feeling' indeed. What kind of system did your friend use, specially enclosures... what kind of music... what he is looking for... the way it express nuances...
The habit to work with musicians, to understand fast what kind of sound they want before a mixing session...
The key is to try to understand his targets and believe that a *honest* designer will share some valuable feelings, (not the love and hate side) because it is an important part of the job to discriminate what we hear.
Even if what he is looking-for is not your cup of tea, you can share informations...
About you ? Ok, i will respond honestly, friendly, even if it is very personal and subjective. (from an old and stupid man ;-)
Obviously, you have a great theoretical knowledge, witch don't seem to go with the friendly, open minded and gentleman attitude witch makes me confident in somebody's sensibility. Often very brutal, near always on the negative side.
You never refer to your own listening impressions, means that is not something you care-of ?
More than that, your crusade against CFAs goes against all my personal experiences.
And you don't even answer when you where asked what CFAs you had experienced... What can-we share in this CFA thread, when i don't even understand what you are looking for here ?
Instead of trying to help-us with all your knowledge to achieve better CFAs, witch is the goal of this thread, you just try to convince-us that we are working on b..s..t. Are-we so stupid ?
"Nobody" was not a reference to any kind of hall of fame, or reference, but something in correlation with 'to be or not to be'.
A man will never be better in any human exercise, technical or artistic, than he is as a human being and his brain better than his heart.
Christophe, I believe Waly is making a good attempt to be constructive instead of being MikeK2.
His last few posts have pointed towards stuff worthy of further investigation. He has also offered good explanations of important points, in a very clear, simple & accurate manner. We should commend such efforts.
As for his question about listening impressions, it is a valid question. As a true Blind Listening Test bla bla guru in my previous life, I also have such questions.
But at the end of the day, some listening tests, even if not Blind bla bla, are better than none. So if the precise details of the test tell me that there may be listening bias, I just adjust the priority I give to this test .. as I might adjust the priority I give to a SPICE sim using dubious models.
Knowledge is always good as long as we know how much credence to put on each item.
But there is no need to be rude even if you think the credence of a particular piece of knowledge is small. There has been too much rudeness from all sides on this thread already .. which detracts from the good stuff that has come out.
We can all agree to disagree on certain points with good humour .. but also give credit to good contributions too.
Personally, I very much hope that Waly might be persuaded to post a design of his own, preferably 'real life' but even SPICE world would be good. This will only happen if he feels in the company of friends.
Pace?
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pure Cherry compensation
For those who wish to try the Holiest of Compensation Methods .. ie 'pure Cherry', may I commend tpc-vs-tmc-vs-pure-cherry.
There is much to learn there, eg how to achieve 1ppm THD20k with simple circuits. Several true gurus explain their caveats on Loony Lee's ravings.
Alas, there is also some cr*p from certain pseudo gurus who are thankfully no longer with us.
For those who wish to try the Holiest of Compensation Methods .. ie 'pure Cherry', may I commend tpc-vs-tmc-vs-pure-cherry.
There is much to learn there, eg how to achieve 1ppm THD20k with simple circuits. Several true gurus explain their caveats on Loony Lee's ravings.
Alas, there is also some cr*p from certain pseudo gurus who are thankfully no longer with us.
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Is it finished? what is the sound?Actually. There is a lot of building going on.
I have 3EF style input in progress.
My last sim with diamond input is 0.6ppm @20k, replacing the diamond with 3EF (soulution710 style) 7pair hexfet OPS only 0.003%THD20 @50W 8ohm.
He has also offered good explanations of important points, in a very clear, simple & accurate manner. We should commend such efforts.
Pace?
In my few interactions with Waly, have found him to be very concise and willing to take the time and use language / explanations that "simple people" (I.e me) can understand.
The following is just an observation and is in no way an attack of any sort!
It appears to me that Waly is like a computer and only accepts correct syntax and all code (communications) must be correct. Logic and accuracy appears to be paramount.
Waly, there are many compensation method able to use in CoD feedback for example is using some inductor between the output of each connected stages. Peak current also easily limited, it is not problem.
He he, on the way to design a no GNFb power amplifier ?
Sorry if my previous post was perceived as rude. I just wanted to open my heart, honestly, with no irony.
And i'm personally really interested in anything (positive) knowledgeable people can bring to this cooperative thread.
I am very moved by the death of J.M. Le Cleac'h. I think to all his work to help the whole audio community with the design of better horns... And all this wasted time to argue with 'horns are no good' attacks when life is so short and fragile.
No, not everything. There is eternal knowledge.
Just curious what if triple EF used as input stagesHe he, on the way to design a no GNFb power amplifier ?
, will it sounds similar with OPS application or not. I found no one tried it before. THD is not bad and still very good in low impedance load.Attachments
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We certainly like to think so. But I do feel that I am enjoying the final years of Class AB audio. 50 years ago was the hey-day for tubes; there have been resurrections (SETs) and there are plenty of us who still like to use them - but since the 1970's the mainstream has been transistors. A lot of great stuff was done with Class AB solid state, the Japanese invested in ever better power transistors for all our benefit and a great many interesting topologies were developed - some exciting stuff from JLH for example.
Even tubes continued to evolve after transistors came on the scene, with new innovations, new design practices and better passives to go with. Working in tubes at that time would still have been exciting and transistor amps would have seemed not quite up to snuff.
I think this is repeating itself now, with Class AB still innovating and people saying Class D is not ready. However, like it or not, we are entering the era of Class D and the bulk of new investment is going into this 'new' technology with the development of better and better topologies, better switching FETs etc.. The young guys are working with switching technologies and improving them, only the old boys are going to be playing with Class AB. Some transistors are harder to find that some tubes. Knowledge may not become obsolete but it will need to be refreshed for new technologies.
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And yet tubes and analog are growing in the market, digital turns to streaming and people no longer has a sense of ownership, Albums are no longer being heard in full content like the artist intended it. Analog restores that and makes the endless zapping 15 sec track an almost physical exercise.
The market is as a whole declining, but analog and 2. channel is growing double digit.That pleases me.
The market is as a whole declining, but analog and 2. channel is growing double digit.That pleases me.
Era of "cheep".
The "new technology" is to raise the bottom line. An acceptable 5.1 amp
to blast out corporate garbage. All made in the "workshop of the world" .
Walmart (corporate fascism - not political , just a valid description) 10$ to make,
class D disposable appliances.
PS - I bet that you won't be able to legally sell an amp that has less than 85%
efficiency in 5 years .
We DIY'ers are the "insurgency" - rebels. May we let the "pitchfork villagers"
hear our creations. I have had some say "that's louder/clearer than my 500W
(PMPO) amp" ... I say "they lie".
OS
The "new technology" is to raise the bottom line. An acceptable 5.1 amp
to blast out corporate garbage. All made in the "workshop of the world"
.Walmart (corporate fascism - not political , just a valid description) 10$ to make,
class D disposable appliances.
PS - I bet that you won't be able to legally sell an amp that has less than 85%
efficiency in 5 years .
We DIY'ers are the "insurgency" - rebels. May we let the "pitchfork villagers"
hear our creations. I have had some say "that's louder/clearer than my 500W
(PMPO) amp" ... I say "they lie"
.OS
For the last decades product development has had the object of making something almost as good, but only cheaper. Few companies are on the path of actually making something better. Those that really are pushing the performance envelope all belong in a tiny niche.
Yet when we really look at it then the top products has never been better than they are today.
Yet when we really look at it then the top products has never been better than they are today.
I don't think so, why would a class AB designer want to cripple his designs with colored, non-transparent reproduction??
And a few (top notch) class D designers are already leaving class AB in the dust, class A soon as well....
Jan