Audio Power Amplifier Design book- Douglas Self wants your opinions

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Douglas,

After reading the 5th edition (and I liked it very much)?

1) A bit more on different topologies.
2) Selection help on power transistors.
3) Selection help on driver transistors.
4) Different compensation schemes.
5) More about CFB and comparing CFB/VFB.
6) What next? Let me rephrase, now that we have these very good tools, simulation and real, and now that we have these very good designs, how do we progress, where is the next frontier, what needs to be done. This is not about the answers, but more about the remaining questions. Like, what do I need to solve to make a real contribution :) Give us something to set our teeth in :)

Regards,
Frans.

There will be a lot more on 1 and 4, and some more on 2 and 3.

5, probably not.

Thanks for your help.
 
Doug,
What time frame are you looking at to produce another book? I already have two of your books and was looking at the current amplifier book you already have to add to my collection. Will you offer any kind of pre-purchase for the book for the DIY crowd. I think that Cordell already has a fairly simple couple of chapters on class D for those that want to read about that. As you say it is a completely different animal to an analog approach. Another area that could use some work is on the power supply side design and perhaps even something on circuit layout and minimization of ground loops and ground plan pointers.
 
6) What next? Let me rephrase, now that we have these very good tools, simulation and real, and now that we have these very good designs, how do we progress, where is the next frontier, what needs to be done. This is not about the answers, but more about the remaining questions. Like, what do I need to solve to make a real contribution Give us something to set our teeth in

There will be a lot more on 1 and 4, and some more on 2 and 3.

5, probably not.

Thanks for your help.

Thanks for your response; I will surely be buying, and reading, the new book.

Do you have any thoughts about point 6, or is it too far out :)

Regards,
Frans.
 
Mr. Self,
I parrot what others are saying here and would expand on an area of the chip amps that I do not see much in the technical literature. That would be higher power applications using chip amps. How best to implement bridge/parallel circuits using these chip amps for higher power requirements. All the information that I find, most from the former National Semi, has been discredited by most on this diy forum as being poorly implemented and problematic. Many are attempting to use these chips as can be seen by the many gainclone threads but the higher power applications are lacking.

My experience with chip amps (or anyway some of them) is quite extensive. It is not however happy. I find them unreliable- even now, apparently reputable manufacturers will produce whole batches that fail quickly, though not quickly enough to be caught during test. A nightmare.

It is for this reason I give this topic a low priority.


I am afraid I am not able to answer everyone individually, but thank you all for your help.
 
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Doug,
What time frame are you looking at to produce another book? I already have two of your books and was looking at the current amplifier book you already have to add to my collection. Will you offer any kind of pre-purchase for the book for the DIY crowd. I think that Cordell already has a fairly simple couple of chapters on class D for those that want to read about that. As you say it is a completely different animal to an analog approach. Another area that could use some work is on the power supply side design and perhaps even something on circuit layout and minimization of ground loops and ground plan pointers.


I hope it will be this year, but I cannot give you anything like a firm date. Getting a book into print takes longer than you might think.
 
My experience with chip amps (or anyway some of them) is quite extensive. It is not however happy. I find them unreliable- even now, apparently reputable manufacturers will produce whole batches that fail quickly, though not quickly enough to be caught during test. A nightmare.

It is for this reason I give this topic a low priority.

I am afraid I am not able to answer everyone individually, but thank you all for your help.

Hello

Maby you could do a thread in the forum about those problems with chip amps ?

If you are tight in time, maby you can start this thread by a short overview of the problems that you have faced with chip amps, and a discution by the forum members will follow.

Thank

Bye

Gaetan
 
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Douglas,
I understand the undertaking it is for writing a book, I was once asked to do that and got as far as the outline and saw how much work it was going to take. It was in a totally different field but I feel for anyone attempting to do it on any technical subject. I may go back and do it now that I am not under the gun so to speak, but it is a tremendous amount of work. I appreciate the Self On Audio book and the Active Crossover books, both well written.

Steven
 
Hi
Do you build and test your own designs, or is only simulated?
I think it is a difference between simulation and then testing the real thing.
But I loved your articles in wireless world and electronics and the pwr amp design book 3rd edition. I built the blameless class a amp, not bad.
Best regards,
Williams
 
Err.. doesn't TPC mean 2-pole compensation?

I meant to compare Two Pole Compensation with what Edmond Stuart named Transitional Miller Compensation.
There was an exhaustive discussion on the reality or otherwise of any real difference between the two techniques.There is an analysis that shows them identical but it is based on assumptions that are only approximations.
I interpret that the TMC proponents eventually conceded that the techniques were more similar than they had initially stated.
I believe there is difference that is real but may be minimal.

I look forward to the new edition, I learned a lot from the previous and it is nice to be able to say thank you directly and make a small contribution.
I will send a PM of typos and the like.

Best wishes
David
 
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Hi
Do you build and test your own designs, or is only simulated?
I think it is a difference between simulation and then testing the real thing.
But I loved your articles in wireless world and electronics and the pwr amp design book 3rd edition. I built the blameless class a amp, not bad.
Best regards,
Williams

I most certainly do build and measure them, with the highest-spec Audio Precision equipment available.

For several reasons, Spice simulation does not give accurate distortion results for power amplifiers. To rely solely on simulations, as some people do, renders their results of little value.
 
I meant to compare Two Pole Compensation with what Edmond Stuart named Transitional Miller Compensation.
There was an exhaustive discussion on the reality or otherwise of any real difference between the two techniques.There is an analysis that shows them identical but it is based on assumptions that are only approximations.
I interpret that the TMC proponents eventually conceded that the techniques were more similar than they had initially stated.
I believe there is difference that is real but may be minimal.

They are certainly not identical. The two methods do quite different things in quite different ways. I'd be interested in a link to wherever it is that someone claims to have proved they are the same. Should be amusing...

I think the more accepted name for TMC is Output-Inclusive Compensation. May not roll off the tongue, but it does at least describe what it does.
 
That really is not going to happen.

Perhaps not, but it might be useful to have unity gain power amps since a preamp with 20-30V output is not a difficult thing to build (especially for tube guys, but easily done with transistors as well). I would think that there's at least a theoretical advantage for noise and noise pickup by arranging gain structure this way.
 
Sy,
I would think that may be useful to a diy guy like you who can build their entire system integrating the pre-amp and power-amp but out in the wild I could just see someone hooking that much input voltage up to a normal power amp and things would get really messy very quickly. Most amps are looking for 1-3volts input, what would you do then? Seems you would have to have matched pairs or integrated amplifiers for any consumer or pro-audio application. I think we would see a lot of smoking amplifiers out there.
 
New Edition

Hi
Is it possible to include information (circuits, comparisons, comments) on soft start and protection systems. These are rarely if ever included in text books.

More information on the use of multiple output transisters and mosfets would also be helpful. Particularly the changes that need to be made to the driver stage.
Don
 
Sy,
I would think that may be useful to a diy guy like you who can build their entire system integrating the pre-amp and power-amp but out in the wild I could just see someone hooking that much input voltage up to a normal power amp and things would get really messy very quickly.

I was under the impression that Doug's books were targeted toward advanced diyers and engineers, not shoppers at Circuit City. Diyers can do any non-standard thing they like to optimize system performance without worrying about standards or universal applicability (e.g., my phono preamp, set up for balanced cartridge operation). The traditional gain structure is honored by its antiquity and universality, not for its optimality.

Perhaps not all would like to have this particular gain structure, but it would be nice as an option.
 
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