Just mention casually that they're on the trailing edge, you're there to help them get up to date and suggest they have a look at what's really happening, like this.
@OnAudio
Your model needs more foundational justification. Why the particular modeling? What is the underlying purpose or need for new modeling? Why introduce unknown functions, why is there a need for that? For one consideration, its not clear why sending out a drive signal results in feedback with what appears to include subtractive information loss.
Your model needs more foundational justification. Why the particular modeling? What is the underlying purpose or need for new modeling? Why introduce unknown functions, why is there a need for that? For one consideration, its not clear why sending out a drive signal results in feedback with what appears to include subtractive information loss.
'The Monolithic Op-Amp: A Tutorial Study' by James E. Solomon (ISSCC Invited Paper)
This was an invited paper at the ISSCC in 1974 by James Solomon, who at the time worked for National Semiconductor (acquired in 2011 by TI).
This paper represents a snapshot of the state of the art in 1974 with respect to integrated operational amplifiers and should be read in that context.
What is interesting about this paper is that all you need to know about a Lin topology amplifier (gm front end stage >fast integrator 2nd stage > high current output stage) wt slew rate, setting front end gm and Cdom and compensation design is covered. Unfortunately, connecting the dots outside the semi industry took quite a few years more.
James E Solomon Opamp Tutorial.pdf
This was an invited paper at the ISSCC in 1974 by James Solomon, who at the time worked for National Semiconductor (acquired in 2011 by TI).
This paper represents a snapshot of the state of the art in 1974 with respect to integrated operational amplifiers and should be read in that context.
What is interesting about this paper is that all you need to know about a Lin topology amplifier (gm front end stage >fast integrator 2nd stage > high current output stage) wt slew rate, setting front end gm and Cdom and compensation design is covered. Unfortunately, connecting the dots outside the semi industry took quite a few years more.
James E Solomon Opamp Tutorial.pdf
Okay. I have seen the paper before. There is also a unique and excellent book on op amps: https://www.amazon.com/Operational-Amplifiers-Second-Design-Engineers/dp/0750693177
But what is the purpose of OnAudio being obtuse about it? Help him with the math? Just to troll?
But what is the purpose of OnAudio being obtuse about it? Help him with the math? Just to troll?
I have an inchoate idea, and it has to do with Chat GPT. OnAudio has shown particular interest in Chat GPT for audio engineering use. The question looks contrived such that an AI would quickly find the paper that most resembled the posted snippet (which in this case requires image recognition). Doubtful the question/bait was intended to be such that a human would easily associate the snippet's similarity with the same paper. Thus, maybe the posts were intended for showing the value of AI for use in answering (possibly contrived) audio engineering questions.
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Let the next discussion begin in 3 .... 2.... 1..... 😉😆
Thanks for the effort again! 🙂 👍
Great article Jan.
You cut right through the BS. This is not a revelation to me, but it's stuff like this that is ripe for sophists to spin. People have so many BS misconceptions of feedback.
I hope someone reads it and sees the light. I wish I had seen articles like this 30 years ago. I had to learn everything the hard way before Al Gore invented the internet.
You cut right through the BS. This is not a revelation to me, but it's stuff like this that is ripe for sophists to spin. People have so many BS misconceptions of feedback.
I hope someone reads it and sees the light. I wish I had seen articles like this 30 years ago. I had to learn everything the hard way before Al Gore invented the internet.
Hi Mark,
Lazy evaluation and abstraction allows for very high level modelling that allows the bigger picture to come out. These unknown functions could be readily populated using currently known functions which are in themselves also approximations that may use abstractions that we know such as capacitors, resistors and inductors.
James Solomon does address gm reduction in an innovative manner, but have just seen that paper, will take the time to read it better have just scanned through, or which paper were you referring to?
You should consider yourself lucky - at least you did learn what you learned. With the state of internet and it's inhabitants today, it is extremely hard to learn something that's worth learning and not some nonsensical BS!
Jan
Jan
Patrick, imagine how fantastic the sonic results would be if you did have best THD figures! 😎
I do not think there is a reason why flat and low LG should be better if unity gain loopgain stays same in both cases. To me, it is a myth and better sound just an imagination. Have you ever done a level matched DBT test with both concepts?
Edit: BTW 30dB only loopgain gives you quite dramatic rise of high order harmonics compared to much higher loopgain values. Please see my post #82 in this thread.
https://www.diyaudio.com/community/threads/myths-tricks-and-hey-thats-neat.406418/post-7532084
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I have never understood to the end why one should chase for the least possible distortion in audio power amplifiers ?(0.00000...%) when the vast majority of standard loudspeakers distort a hundred times more, and up to 5% THD, and one should also take into account the sound distortion detection threshold of human ears factor,
however, on the other hand, when it comes to power amplifiers for laboratory precise various application, than I agree that the distortion must be the smallest as possible.
however, on the other hand, when it comes to power amplifiers for laboratory precise various application, than I agree that the distortion must be the smallest as possible.
Correct, it is nothing but technical ambitions of the designer. In any case, stories about wonderful sound are pointless if they are not supported by valid DBT results. I am with SY on this. Yes, not in the line with enthusiasm of hobbyists.
It has been argued that the difference between a power amp with 0.1% and 0.01% can be heard even with speakers that distort 3%.
I don't know how solid that is though. May be folklore.
Jan
I don't know how solid that is though. May be folklore.
Jan
It would be nice to see the link with description of test conditions. I only hope the test was not done with a pure sine wave of frequency and level at the most sensitive human ear area. With a pure sine, threshold of audible harmonic distortion is much lower than with any kind of music signal. If we do not have a link to a publication or exact test description, we have nothing.