Clint Eastwood: "Opinions are like ********, everybody's got one."
While somewhat harsh, the above is not completely untrue.
To me, Bob Cordell's book is the best I have ever seen by far because of two things:
1. He didn't go all theoretical on the reader, and I believe if he had, that would have put far too many people off. He stuck to what is most important (good selection there) and told it in easily understandable language, and
2. He backed up his claims (so to speak) with actual models. He turned his words into practice and NOTHING inspires confidence as that does, nor makes understanding so easy.
While somewhat harsh, the above is not completely untrue.
To me, Bob Cordell's book is the best I have ever seen by far because of two things:
1. He didn't go all theoretical on the reader, and I believe if he had, that would have put far too many people off. He stuck to what is most important (good selection there) and told it in easily understandable language, and
2. He backed up his claims (so to speak) with actual models. He turned his words into practice and NOTHING inspires confidence as that does, nor makes understanding so easy.
Wow, is that fast printing and distribution...or what?
My pre-ordered Amazon UK copy is advised due for dispatch in September.....hmm!
Hi Guys
SY, I think some would view the books discussed here as "amp porn". I do. But I like schematics and graphs and explanations that make sense.
There are other "amp porn" books with pictures of amps and descriptions of the designers and personalities of companies and the whole social evolution that goes along with it. To each his own. I don't find those books to be as interesting.
I know a farmer who looks at "fruit porn" as he has an apple orchard.
The best part of Bob's book is Ch.3 where he shows an amp evolution from very basic to fully featured, with attendant explanations of how performance improved and why, along with THD measurements - er, sims. You can see how much each incremental change improves the spec to have a better appreciation for the impact of those elements in other designs.
Have fun
Kevin O'Connor
SY, I think some would view the books discussed here as "amp porn". I do. But I like schematics and graphs and explanations that make sense.
There are other "amp porn" books with pictures of amps and descriptions of the designers and personalities of companies and the whole social evolution that goes along with it. To each his own. I don't find those books to be as interesting.
I know a farmer who looks at "fruit porn" as he has an apple orchard.
The best part of Bob's book is Ch.3 where he shows an amp evolution from very basic to fully featured, with attendant explanations of how performance improved and why, along with THD measurements - er, sims. You can see how much each incremental change improves the spec to have a better appreciation for the impact of those elements in other designs.
Have fun
Kevin O'Connor
Hi Guys
Amazon.com (usa) says "in stock, 18 left" but their price is higher than at amazon.ca (Canada) which still says "arriving July 13". I'll take the lower price in exchange for a few more days.
As usual, suppliers pander to USA demand in priority of availability. Just because they're the biggest consumers.... the best customers... really nice people....
Have fun
Kevin O'Connor
Amazon.com (usa) says "in stock, 18 left" but their price is higher than at amazon.ca (Canada) which still says "arriving July 13". I'll take the lower price in exchange for a few more days.
As usual, suppliers pander to USA demand in priority of availability. Just because they're the biggest consumers.... the best customers... really nice people....
Have fun
Kevin O'Connor
Then let me add another opinion to that one:
Those comments would apply to either book/author. I don't see a lot of difference in technical level but Bob's declared target audience is DIY audio members - us.
When Doug prepared his first edition, forums like this didn't exist and as I understand it, his target was manufacturers. The focus may have moved somewhat but I'm sure he'll correct me if otherwise. Some will just love having familiar issues thrown at them again and discussed methodically in a book. Others will like something from outside their forum world. perhaps some real world or commercial ideas which help explain why people go about design in radically differently ways when standards have to be met.
I like both sets of ideas and approaches and I think there's room for even more, if it made everyone an income, at least.
Thank you so very much for these kind words. I'll try to stay on that track in the second edition, while improving the existing material and adding new material.
Suggestions from the DIY community help a lot, and I try to listen to all of them (I'm keeping a list that is getting quite lengthy).
Cheers,
Bob
Hi Guys
Bob, are you also averse to producing a new book rather than a second edition?
Just as Doug truly has, you also have enough new info to warrant a separate book.
Please have respect for the people who have already bought the first edition. Why make them pay again for the same information? (I know you have that respect, Bob, as your voluminous and detailed and angelically patient posts display. I just hate 'editions' when 'volumes' are justified).
I suppose holding this view - and worse following it - makes me a poor businessman in all senses of that phrase. I produced eleven books so far with more in the works, all fairly different - at least more different than similar. If I had only followed Doug's example and made my customers pay five, six, seven times for the same stuff.... surely they would have been agreeable to that?... just not my style.
Bob, I have great respect for you and Doug, as people and as engineers and as teachers, and for all the work you've presented. I just hate the dogmatic corporate money grubbing that must be at issue for resale after resale after resale.
Have fun
Kevin O'Connor
Bob, are you also averse to producing a new book rather than a second edition?
Just as Doug truly has, you also have enough new info to warrant a separate book.
Please have respect for the people who have already bought the first edition. Why make them pay again for the same information? (I know you have that respect, Bob, as your voluminous and detailed and angelically patient posts display. I just hate 'editions' when 'volumes' are justified).
I suppose holding this view - and worse following it - makes me a poor businessman in all senses of that phrase. I produced eleven books so far with more in the works, all fairly different - at least more different than similar. If I had only followed Doug's example and made my customers pay five, six, seven times for the same stuff.... surely they would have been agreeable to that?... just not my style.
Bob, I have great respect for you and Doug, as people and as engineers and as teachers, and for all the work you've presented. I just hate the dogmatic corporate money grubbing that must be at issue for resale after resale after resale.
Have fun
Kevin O'Connor
Hi Kevin,
I understand your concern. I have 3 of Doug's volumes and a 4th (the new edition) on the way. But bear in mind the number of years over which Doug's editions stretch.
Given the pace of technology, interest of the audience, and the constant learning, experience and research of an author, a new edition every 4 years or so is reasonable.
The alternative, letting a first edition die on the vine, can set up an awkward situation, and force entirely new readers to read a dated book if they want that material.
I guess what I'm saying is there are no easy answers.
And I have not even yet mentioned the wishes of the publisher, which can sometimes trump many other issues.
You're right about the amount of material, and this is always an issue. But if some of the material were split off, the new book might not stand on its own. As a perfect example, I'm glad I put all of the SPICE information into the book in those two chapters because I deemed it important for the reader to be fully able to take advantage of the material in the book. But I am not a SPICE expert and it would be presumptuous for me to write a book on SPICE, and I'm sure it would fall flat on its face.
I'm really impressed that you've written so many book. I know how much work that must be!
Cheers,
Bob
Hi Guys
I will admit up front that despite my books being the heaviest tomes in the niche they own... er... inhabit... they are not as heavy as yours and Doug's. My fourth book followed in the foot steps of the first, as the second volume of the same series. However, at the time I had some of the same wonderments as you stated, regarding having the book stand on its own. There ended up being some overlap between the two as a result.
By the time I got to the third volume of that series, I had come to the realisation that they could be built in an "encyclopedic" fashion. The opportunity to map the whole series from basics to complex was already lost, so each volume introduces its own topics and may revisit and expand on topics from previous volumes.
In similar fashion, if Doug had left the first ADAP volume as the collection of EW articles that it in fact was, subsequent volumes could easily build on that base without repeating the original content. Sure, there are things you would like to go back and change or update, but those updates are welcome to readers in the later volumes. They get to see that even in the case of a contradiction that the 'expert' has learned something, just as the reader is learning. I think this makes everything more acceptable and brings a humanity to the experience of writing and reading.
I'm way behind on what I'm supposed to have written, but the delays mean better content and better writing. I assume the 'edition' push is from the publisher as they can spit out something that is already a known seller.
Have fun
Kevin O'Connor
I will admit up front that despite my books being the heaviest tomes in the niche they own... er... inhabit... they are not as heavy as yours and Doug's. My fourth book followed in the foot steps of the first, as the second volume of the same series. However, at the time I had some of the same wonderments as you stated, regarding having the book stand on its own. There ended up being some overlap between the two as a result.
By the time I got to the third volume of that series, I had come to the realisation that they could be built in an "encyclopedic" fashion. The opportunity to map the whole series from basics to complex was already lost, so each volume introduces its own topics and may revisit and expand on topics from previous volumes.
In similar fashion, if Doug had left the first ADAP volume as the collection of EW articles that it in fact was, subsequent volumes could easily build on that base without repeating the original content. Sure, there are things you would like to go back and change or update, but those updates are welcome to readers in the later volumes. They get to see that even in the case of a contradiction that the 'expert' has learned something, just as the reader is learning. I think this makes everything more acceptable and brings a humanity to the experience of writing and reading.
I'm way behind on what I'm supposed to have written, but the delays mean better content and better writing. I assume the 'edition' push is from the publisher as they can spit out something that is already a known seller.
Have fun
Kevin O'Connor
Hi Guys
Bob, a further thought, as I was just talking to my publisher... hehe
Where you personally do not think of yourself as an expert on simulations, as your example, the fact is that if you put your sim info, EKP models and whatever new info you have about that into its own volume, it would certainly sell well. The problem is that your publisher does not know that it will sell.
The same applies, say, to the class-D info. Linear guys don't really care about class-D and don't want to have to pay for that in a "linear" book. Again, your publisher would be surprised at how well a Bob Cordell Class-D book could sell.
That pace of change, growth and technological development you speak of certainly justifies a new volume coming out every few years... to me, not a new edition.
It does not matter at all that you do not feel yourself to be the go-to-guy for sims - although many here would say you are - or that you don't feel expert enough to have a dedicated book about whatever other niche, but... the reading public is insatiable and wants all that it can get. If everyone writing on technical subjects waited until they knew everything about the subject before writing a book, there would be no tech books.
I do not know everything about my subject area but I have a unique view that people want to know about. I was lucky inasmuch as there were no books covering this field when my first book went out. It was truly an experiment but one that panned out.
Doug should realise the same lessons. He could have several volumes of ADAP covering different things, with later ones updating older ones without major or even minor overlap. People have to spread their funds around on bills and their entertainment, and most won't buy a dozen copies of the same record, or movie, or book if they have a choice not to. They will eventually refuse to buy copies of what they have just because the supplier says they should.
Have fun
Kevin O'Connor
Bob, a further thought, as I was just talking to my publisher... hehe
Where you personally do not think of yourself as an expert on simulations, as your example, the fact is that if you put your sim info, EKP models and whatever new info you have about that into its own volume, it would certainly sell well. The problem is that your publisher does not know that it will sell.
The same applies, say, to the class-D info. Linear guys don't really care about class-D and don't want to have to pay for that in a "linear" book. Again, your publisher would be surprised at how well a Bob Cordell Class-D book could sell.
That pace of change, growth and technological development you speak of certainly justifies a new volume coming out every few years... to me, not a new edition.
It does not matter at all that you do not feel yourself to be the go-to-guy for sims - although many here would say you are - or that you don't feel expert enough to have a dedicated book about whatever other niche, but... the reading public is insatiable and wants all that it can get. If everyone writing on technical subjects waited until they knew everything about the subject before writing a book, there would be no tech books.
I do not know everything about my subject area but I have a unique view that people want to know about. I was lucky inasmuch as there were no books covering this field when my first book went out. It was truly an experiment but one that panned out.
Doug should realise the same lessons. He could have several volumes of ADAP covering different things, with later ones updating older ones without major or even minor overlap. People have to spread their funds around on bills and their entertainment, and most won't buy a dozen copies of the same record, or movie, or book if they have a choice not to. They will eventually refuse to buy copies of what they have just because the supplier says they should.
Have fun
Kevin O'Connor
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Not at all, Bob, my words merely reflect my feelings.
To me, quality is quality, never mind whether I completely agree with it or not. In a sense, I'm from "the other camp", i.e. I like small amounts of global NFB, in the mould of Otala, Harman/Kardon, etc. However, I recognize the fact that there are many ways to go about it, each with its ups and downs.
I also reognize a paradox I've been observing for at least 30 years. Put 3 TV sets on a table, assemble a jury presumed to be qualfied and have them choose the best one. It may take i little time, but chances are they will eventuall agree on one model.
Repeat the same with any audio device, and chances are they will never agree. Especially regarding amps and loudspeakers.
The paradox is that as (medical) doctors tell me, our sense of hearing is thought of as less acute than our sense of sight.
My only suggestion would be that you take a little time and space in your bext edition to cover the two (most?) opposing trends overall, the little local much overll NFB vs much local, little global NFB approaches. To put it in prespective. Assuming your current edition describes the approach you prefer personally, the challenge is writing objectively about the other approach.
conflating 2 very different cases there
amps don't vary anything like loudspeakers, in fact many "good" amplifiers could be made to "sound the same" with little tweaking, output impedance padding to give >60 dB nulls between them – should be effective pretty much up to their respective power rating
but with loudspeakers even EQ-ing the on axis response - they still won't sound "the same" if they use different drivers of different sizes on differently shaped boxes and they could each be from major different schools of directivity - omni, controlled, line source, mono/di-pole...
good amps don't have to – and probably shouldn't sound different
for loudspeakers we really don't even have a single target corresponding to the "wire with gain" goal for amps
I'm sorry, JCX, but amps DO sound differently.
I only have to look at what I have at home, I need go no further. Marantz, Sansui, Harman/Kardon and Karan Acoustics - 4 amps, 4 different results on any of my 3 pairs of loudspeakers, in 3 different rooms. With fairly consistent differences across the board.
I agree that the differences in sound are most likely to be greater with speakers than with amps (almost always so).
I only have to look at what I have at home, I need go no further. Marantz, Sansui, Harman/Kardon and Karan Acoustics - 4 amps, 4 different results on any of my 3 pairs of loudspeakers, in 3 different rooms. With fairly consistent differences across the board.
I agree that the differences in sound are most likely to be greater with speakers than with amps (almost always so).
Just preordered my copy this morning. 9th to 12th August estimated delivery.
(Amazon keep asking me if I want to trade in Bobs book
Lets keep this tread going with with trivia . I will get my copy and we all can have a party of sorts .
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I thought the first exemplars were sold in the late 1970's (78 or 79)
Philips version may have been done in 1990' but it was certainly out before that.
It was DOD'd by Philips in about 2003. I asked the PL Manager (who was based in the valley) why. Answer: we dont make enough money on it.
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Dvv . A challenge for anyone who has bits in the shed . Find a chip amp with a circuit reasonably like the blameless design in the handbook . Build three amps all identical . Three power supplies . One , the minimum required , Next the best you can with lets say 200% spare current . The third a switch mode . I bet they all measure the same ? And the next question is , do they sound the same ?
Give a hint for some values.
Say 60VA & 4700uF+4700uF for a 60W amplifier, then 180VA & 15mF+15mF (for 3times the current for the same 60W amplifier and finally a pair of 180W SMPS, or should that be a pair of 30W smps for the dual polarity supply?
Is that what you mean?
Bought a copy today, paid extra for quick delivery tomorrow. Screen shot below.
Attachments
not if you're half competent, know what to measure - even a good US$150 sound card could "see" the various capacity PS differing loaded ripple through a LM3886 ~100 dB -PSRR with fc rignt at mains frequency
and that's just if you restrict "measurement" to audio input test signals, look at audio output under load
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