Please take into account they were simulation results only. Simulation is just a 1st step. I can make you sure that when measuring a real prototype, distortion results may be very often one order or more worse, than the simulated results. Simulation is only as good as component models and especially MOSFET power transistor models are usually quite far from reality. Then, there are factors like PCB design, ground topology, PSR impulses induced distortion and many others. So, as long as you do not have a real sample built, it is very difficult to guess from simulation. Simulation just shows limits you may, or may not achieve in a real circuit.
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- Thread starter Tournesol
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Please take into account they were simulation results only. Simulation is just a 1st step. I can make you sure that when measuring a real prototype, distortion results may be very often one order or more worse, than the simulated results. Simulation is only as good as component models and especially MOSFET power transistor models are usually quite far from reality. Then, there are factors like PCB design, ground topology, PSR impulses induced distortion and many others. So, as long as you do not have a real sample built, it is very difficult to guess from simulation. Simulation just shows limits you may, or may not achieve in a real circuit.
- Thread Starter
- #23
+1. Clever remark. Reason why I insisted on telling it was only "simulated" results.
(One of the indications of the limit of our "science" ;-)
Let-s say that better simulated results usually tend to end with better performances, if no big mistakes made in the next of the work.
(btw: I used Cordel's for laterals)
What we can say, here, is that they are promising". Right ?
Lot of mistakes/optimisations can be made on the PCB design as well as some choices of passive components (electrolytics, quality of resistances on critical parts like feedback network etc.)
That is some of the points where practical experience and good practices can make the difference and where exchanges between designers can be very productive..
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Speaking as a non expert in anything relevant to audio, I find the discussions between some of our engineers to be fascinating and clearly at a very high level.
If anyone wanted help bringing that design and projected performance to reality, I'm not sure where there would be a better group in terms of technical competence to reach that goal.
If you aren't trying to create some kind of 'voice,' but just want to build a great amp with no compromises, I'm not sure what you are concerned with?
This forum doesn't beat on with people who are here sincerely, especially if they have something interesting to offer which it looks like you may. If you are here to teach, that's going to be a big ask... If you are here you open-mindedly share, who knows who may learn what.
You didn't come in here with some terribly obnoxious introduction...as often happens...you politely asked. That may go further than you think...
Either way, sincerely, best of luck with your design.
- Thread Starter
- #25
Back for a little explanation.
I had said the goal of this project was "exploration". I'm not a teacher or a preacher of any religion. My little knowledge is mostly based on personal experience, tries to think out of the box, exploration, desire to understand subtle things, and a big humility about our little knowledge of all the phenomena in action in audio.
Including pshycho-acoustic and the complex ways our brains compute our listenings experiences. (i was a sound engineer too)
I'm not a superstitious or snobbish audiophile neither, if you see what i mean and technically, I do the best I can FIRST. But not only.
The answer of Thomas savage (talking as a moderator ?)
"Iv no interest in seeing pages of back and forth regarding subjective evaluations and design choices based on those ." ruined my day, made-me very sad and decided me to look for another place. Other definitive comments push me in the same direction.
I'm naive enough to evaluate the quality of my audio works with my ears, with the way that best suits to me, and the one of my photographies (an other passion) with my eyes rather than MTBF and do not want to lose my time in sterile controversies with people that want to impose to others their own views and personal methods.
Ite missa est, I'm not in the church of the "all amps sound the same" neither in the ones of cable lifters and silver wires.
TO PMA, of course, I wanted to share the schematics, LTSPICE files and simulation results , etc. If you like to see other examples of some of my works, you can have a look here:
http://www.esperado.fr/images/stories/protection2.php
If some here could help -me to find a place to exchange with competent, experienced, curious, open minded, and friendly other designers, a space of liberty, it should help-me to recover my smile. The important word, for me is LIBERTY and respect for others. At the end of a project, the result speaks for itself.
Perhaps some introspection about why you were banned twice (under different identities) from diyAudio might be useful.
Or perhaps re-examining your approach to make it more evidence-based might hold you in better stead with skilled engineers and designers rather than the hacks in high end audio who like to play make believe.
Either way, if you want to wear a scientist lab coat and have your design work taken seriously by accomplished practitioners, you have to approach problems like a scientist, which is to say using data, controls, and have a willingness to find that your basic assumptions and beliefs aren't correct. IME, the last is the hardest thing for many people to overcome.
Or perhaps re-examining your approach to make it more evidence-based might hold you in better stead with skilled engineers and designers rather than the hacks in high end audio who like to play make believe.
Either way, if you want to wear a scientist lab coat and have your design work taken seriously by accomplished practitioners, you have to approach problems like a scientist, which is to say using data, controls, and have a willingness to find that your basic assumptions and beliefs aren't correct. IME, the last is the hardest thing for many people to overcome.
- Thread Starter
- #27
I was 'banned' after having said I was leaving and what I thought about the poisonous and aggressive atmosphere created by a a moderation team of which I did not approve the methods and the partiality. They ban all people that question them about their methods. Not a technical question, but general atmosphere. DIYaudio is not a club of gentlemen, that is the most important thing for me. And some people there seems to be encouraged to aggress endlessly and stupidly other members in total impunity.
Strangely? No technically based criticism has been made on the amp on which I work once past the initial theoretical phase that some have taken for a final scheme. Tired of ego stories and personal remarks like your.
This amp show low distortion, good enough stability margins, high speed, flat VAS current VS temperature, nice distortion curves, no rail sticking,. What else ?
Because you seems to know where i'm for the moment with this amp, feel-free to share any technicaly based critics there, I will read-it with interest and open mind. As long those critics are made in a friendly and polite way.
Evidence based ? what is more "objective than LTSPICE with all its known limitations and measuring instruments.
The last thing I want is personal controversy and 'HIGH end" is not in my book. I'm a member of the poor guy hall of fame. A music lover.
Strangely? No technically based criticism has been made on the amp on which I work once past the initial theoretical phase that some have taken for a final scheme. Tired of ego stories and personal remarks like your.
This amp show low distortion, good enough stability margins, high speed, flat VAS current VS temperature, nice distortion curves, no rail sticking,. What else ?
Because you seems to know where i'm for the moment with this amp, feel-free to share any technicaly based critics there, I will read-it with interest and open mind. As long those critics are made in a friendly and polite way.
Evidence based ? what is more "objective than LTSPICE with all its known limitations and measuring instruments.
The last thing I want is personal controversy and 'HIGH end" is not in my book. I'm a member of the poor guy hall of fame. A music lover.
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The more you explain, the more I realize that's probably a very reasonable decision...
Ultima Thule
Member
Hi Pavel,
looking at the attached picture in post 1# in the upper left corner we see pizzicato-v 250..., it's a continuation from the old forum and initially based on the old Elektor Crescendo amp. B)
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Well, as long as you provide more than your ear based opinions, everything's fine. Just remember that ASR is a gentlemen's club, not a gentle men's.
I think building the amplifier then measuring a real one is more 'objective; than a simulation. The simulation that you show is great, but how does that translate to real devices? That would be much more interesting to me.
S.
- Thread Starter
- #32
Hi, Ultima Thule, (Companion in misfortune ? ;-) Thanks for your interest.
May I simply add that the filiation between this project and the old Crescendo is as tenuous as us with the man of Neanderthal ? The only things in common are the use of power FETs and cascoded VAS:
CFA vs VFA, totally different compensation scheme (inclusive), different input stage (Diamond VS LTP) , current source etc.
For the moment, two very good and talented PCB designers (some will see who I mean ;-) are working together on the layout.
I'm looking for a forum where I can exchange with competent and open-minded EE , in a serious and collaborative way , out of personal attack from people talking from their egos, in a nice, gentle, friendly and collaborative atmosphere in order we can optimize this project to get the best of it for the future DIY builders (No business involved). I'm sensible and old, I need friends, not competitors showing their guts.
I dream to find a place where we it is possible to exchange freely about subtle subjective listening differences without having to fight against a bunch of so calling "objectivists' on a mission. Neither to fight against snake oil sellers or snobbish High end ones living in a magic world of fashion.
My problem with Thomas savage answer:
"Iv no interest in seeing pages of back and forth regarding your subjective evaluations and design choices based on those ."
is some of my design choices are precisely based on subjective preferences, or desire to learn/explore more about thresholds of audibility. Those little differences that measurements do not reveal, whatever some believe. But fights with "back and forth" argues is precisely what i want to avoid.
It is a work in progress. A project that i dream to be collaborative. Of course, it has to be build and measured (for the moment, just virtual/simulations) . It is, for me, a first attempt to see if any way to design an amp right from simulators, including PCB layout, letting all the chances to get a final successful amp with just little adjustments of some components values on the bench.
By habit, I work the exact opposite (old) way. Working with real components with listening and measurements at each changes to confirm if any good/better/difference. In my book measurements and listenings as both important and complementary. Amazing measurements numbers only being just another kind of audiophile snobbism.
I had a bad experience on DIYaudio, I want to avoid it at all costs. That I read on ASR seems to me much more sympathetic and reasonable / balanced. Am-i Mistaking ?
My question is always, "What's the problem you are trying to solve?" How to make transparent power amps to drive specified load ranges is something well known for many decades. And there are dozens of books about it, along with hundreds of real-world examples. Recent advances have brought this transparency to amps with extremely high efficiency and small size/cost. So I'm failing to see what the actual target is and why it matters.
That said, sometimes the answer is, "My amp won't sound or perform any better than the hundreds of existing engineered amps, but I just wanted to do it with (fill in the blanks technology) for my own amusement." Sadly, that's rarely admitted.
dkinric
Addicted to Fun and Learning
This seems a reasonable approach, and something that would benefit both OP and the ASR community. By declaring your intentions/expectations up front, and starting a build/discussion thread in the appropriate forum, I see no reason why this should be avoided.
ASR's growth has been significant lately, and posting on any internet forum is never guaranteed inoculation against criticism, but you are also likely to benefit from the knowledge and experience of some of the regulars here with EE and design/repair experience. If you are looking for feedback on design principles of audio devices, this is as good a place as any.
@Thomas savage, your post seems to be giving OP much pause, do you care to expound on your concerns?
ASR's growth has been significant lately, and posting on any internet forum is never guaranteed inoculation against criticism, but you are also likely to benefit from the knowledge and experience of some of the regulars here with EE and design/repair experience. If you are looking for feedback on design principles of audio devices, this is as good a place as any.
@Thomas savage, your post seems to be giving OP much pause, do you care to expound on your concerns?
Esperado/Tournesol has some... history, the worst of which has been erased. I think you might get some beginning hints from Post 32. But again, if the topic stays to design, objective performance, and controlled science-based listening claims, that's great. I am pessimistic about that but would be delighted to be wrong.
My question is always, "What's the problem you are trying to solve?" How to make transparent power amps to drive specified load ranges is something well known for many decades. And there are dozens of books about it, along with hundreds of real-world examples. Recent advances have brought this transparency to amps with extremely high efficiency and small size/cost. So I'm failing to see what the actual target is and why it matters.
That said, sometimes the answer is, "My amp won't sound or perform any better than the hundreds of existing engineered amps, but I just wanted to do it with (fill in the blanks technology) for my own amusement." Sadly, that's rarely admitted.
That approach might be applied to anyone here and there, Stuart. You and me included. To any designer, manufacturer. The result would be - do nothing, anything was already invented. And I do not like this approach. This is our hobby, we like to try, to verify principles, circuit topologies, we like to see and hear the result, because it is our hobby and it brings us some satisfaction. Even if "everything has been already invented", we can see some spots and niches we can still fill in. We can concentrate on some specific issues, regardless cost effectivity, regardless sales and marketing. This is the power of hobby or professional-hobby approach.
Apart from commercial considerations...I want to do it as I think I can sell it and make money..... You're right, any conventional amplifier design today has to be an intellectual exercise for one's amusement. Nothing new to be discovered. Even Class D amps are now largely a solved problem, although perhaps making them smaller, lighter and cheaper whilst improving performance can be intellectually challenging.My question is always, "What's the problem you are trying to solve?" How to make transparent power amps to drive specified load ranges is something well known for many decades. And there are dozens of books about it, along with hundreds of real-world examples. Recent advances have brought this transparency to amps with extremely high efficiency and small size/cost. So I'm failing to see what the actual target is and why it matters.
That said, sometimes the answer is, "My amp won't sound or perform any better than the hundreds of existing engineered amps, but I just wanted to do it with (fill in the blanks technology) for my own amusement." Sadly, that's rarely admitted.
In the case of the OP, it looks like this is a personal venture, rather than a commercial activity, so good luck to him, but as to the 'listening' part of the design process, it seems rather pointless except as a reality check on the measurements.
S
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