Let me tell you a story. Being a student I developped in the early eighties a Leslie simulating circuit that I presented Dynacord and they marketed it as CLS22 and CLS222 respectively. This was the first time I got some insight of the professionals working in industry. Like you, I expected their knowledge far exceeds my amateur knowledge. But I had to learn this was not the case. None of the the experts was capable of understanding the whole circuitry so I had to deliver the entire checklist for production final test procedure. And yes, I did the whole PCB-layout as well, with tapes on paper, scale 4-by-1 during one week in Straubing/Bavaria.
So what I learned was all these guys are not gods, but humans with restrictions, sometimes lazy, sometimes reluctant - just like me
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Let me tell you a story. Being a student I developped in the early eighties a Leslie simulating circuit that I presented Dynacord and they marketed it as CLS22 and CLS222 respectively. This was the first time I got some insight of the professionals working in industry. Like you, I expected their knowledge far exceeds my amateur knowledge.
But I had to learn this was not the case. None of the the experts was capable of understanding the whole circuitry so I had to deliver the entire checklist for production final test procedure. And yes, I did the whole PCB-layout as well, with tapes on paper, scale 4-by-1 during one week in Straubing/Bavaria.
So what I learned was all these guys are not gods, but humans with restrictions, sometimes lazy, sometimes reluctant - just like me
Hi thank you sincerely for the very telling story. I like also quotes from famous scientist like Einstein. There is this one buzzing in my head ...
is that simple as possible that leaves me
My feeling is that instead of optimizing good simple maybe textbook designs some designers have taken the complexity route introducing much more variables to the equations.
From what i understand that started in the 80s and someone actually is re-discovering amps designed in the 70s like the Quad, HK Citation twelve, and many other vintage units.
That famous simple design has some flaws and shortcomings too.
There are two main routes:
Commercial; make as cheap as possible, sell for as much as possible.
You're puzzled why there are still crappy designs.
Artistic; build as good as possible, show it on DIY fora and such.
You're puzzled why there is so much discussion.
Good designs yet not commercial: Pass, Hiraga. And many others, not to forget to mention.
There are two main routes:
Commercial; make as cheap as possible, sell for as much as possible.
You're puzzled why there are still crappy designs.
Artistic; build as good as possible, show it on DIY fora and such.
You're puzzled why there is so much discussion.
Good designs yet not commercial: Pass, Hiraga. And many others, not to forget to mention.
> i understand that started in the 80s and someone actually is re-discovering amps designed in the 70s
ALL design runs in loops.
All design is a product of its time.
A different example: early 'gasoline' piston engines put the valve(s) next to the cylinder for simplicity. A later generation put them above the cylinder for better power. Another generation put them back next to the cylinder for easier mass-production and reduced noise. 1947 they put the valves over the cylinder for improved power ("horsepower wars" of the 50s and 60s). And a few years ago an aircraft engine was proposed which put the valves back next to the cylinder for reduced overall width (more engine in narrow fuselage).
ALL design runs in loops.
All design is a product of its time.
A different example: early 'gasoline' piston engines put the valve(s) next to the cylinder for simplicity. A later generation put them above the cylinder for better power. Another generation put them back next to the cylinder for easier mass-production and reduced noise. 1947 they put the valves over the cylinder for improved power ("horsepower wars" of the 50s and 60s). And a few years ago an aircraft engine was proposed which put the valves back next to the cylinder for reduced overall width (more engine in narrow fuselage).
Oh, sorry I had to mention these good 'artistic' yet commercial designs and products. Most are eyepopping expensive (good stuff used to build them) or nice and really acceptable. Even the well known japanese corporations have proved they're able to make affordable top rated products alongside with more humble solutions.
99.9% of most listeners to audio in households, shopping malls, hotels and you name it does not even bother the tiniest bit what we're discussing here.
99.9% of most listeners to audio in households, shopping malls, hotels and you name it does not even bother the tiniest bit what we're discussing here.
How would you do to optimize it? Optimize the performance BUT keep the amount of component and stages simple?? I have tried to do what i think you want to do. Let's start with the input stage and VAS.
Popular books on amp design started with this very schematic then improve it with the addition of transistor or gain stage. A stage is known as 'beta enhancer', which implies that if you have 'sufficient' beta you don't need this stage. So you can start with choosing the right transistor and 'select by hand'. A good transistor with high beta is MPSA18, which is an npn without complementary pair, so you might want to flip the polarity of the cct. My favorite was BC546C, not as high as the MPSA but is more linear etc. I have C2240BL and C3324 smd which would be nice if you can get hfe above 500.
Next is feedback resistor. Resistor noise follow typical exponential curve. 33k has probably closer performance to 100k than to 20k. They say, keep the resistance below 1k to ensure low noise. I think 33k is not a good number. You can still get away with less input impedance. I have experimented with series and parallel arrangement for FB resistors. My current practice is using the same type resistor for Rf and Rg. Rf is using four 10k to make up 10k and Rg is using two 1k to make up 500 Ohms. Jan Didden mentioned 20x of 1k for Rf and a 1k for Rg. I have prepared using 560 Ohms instead of 1k but it is difficult to arrange 20 resistors nicely.
Those two are only small examples of how to 'optimize' without complicating the circuit. The one that requires more knowledge is how to get the highest stability with the same cct.
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Hi ! that HK designers missed ? i understand they based this design in some application notes from RCA the manufacturer of the output devices ?
ok i see ... but how much the design cost adds to the production cost when it is divided for all produced units ? and considering that for many years the amps design has been basically kept the same ...
that is the worst part of all ... because this projects remain available to only few people. I have to add that new generation are not so hot for hifi. They spend their time on earphones connected to smartphone.
I think their like more noises than music ... but that is ...
From a practical point of view i see class A and tubes a little scaring for the average customer ... but not a good sounding class AB design
I see. I read somewhere that at the time the reference sound was the one of tube amps ? so solid state amps should mimic that sound to be accepted.
If this is true this is interesting because many people like the sound of valves or tube like solid state ... i like it a lot but despise the bass from tubes. This is a show stopper for me ... never tubes on the bass.
i think they are very different fields. For engines we can measure power and torque and establish a ranking.
In audio amp a smaller power amp can sound better than a higher power amp and often it does. It is more difficult to establish a ranking for sound quality. I guess.
I see. Clearly people really involved in serious music listening are much fewer these days. I stopped to go to audio fair because i cannot stand people talking during the demo. Why are there and do not go to the bar to discuss ? very very unrespectful of sellers and listeners.
Music is a very intimate experience ... especially classic and jazz ...
Missed or intentionally left out to reduce costs.
Application notes are sets of ideas to apply, and to promote!
The better the profit becomes over years.
Enthusiasts, devotees, gurus. It's a niche market.
All said, you have a very honest and sharing character, but you're a minority these days. Everybody has some opinion and political preferences. We cannot remake the world according to this. Better so and alas.
Good morning ! my point was that they can be a very good point to start. I would be surprised to know that they propose not working schematic for instance. Even more interesting can be evaluation boards that almost nobody care ...
ok. Maybe some very good diy project can have a market. In the past the kits were more popular but as i said before a lot depends on the new generations. Young people spend their listening time connected to their smartphone ... for sure they do not give a damn to soundstage rendition, tone, details ... and they often listen to noise not music.
i think that there is a passion for caos ... or at least someone is promoting it.
I have a bad feeling. I really hope i am wrong.
I regret the 70s' and 80s ... much better years. And incidentally years of great music.
Oh, it does work, that's for sure. Practical applications render into 'slightly' different solutions although.
We live in a different time then we can remember (you're two years my senior). I call it a topsy turvy reality compared with what was once. Alas.
Hi again ! yes time have changed a lot. I was watching young people ... they have always earphones on ... so they listen a lot more music but what music ? and with which quality ?
maybe if i talk with them about soundstage they look at me strangely ...
For me listening to headphones after a while is really unbearable ... this feeling of sound inside my head.
I like music coming from the space in front of me.
This is impossible with headphones of course.
> I like music coming from the space in front of me. This is impossible with headphones of course.
When you put on hearing aids (or test microphones through headphones), when you talk your own voice may sound like it is "in your nose".
Remarkably *small* adjustment of gain or EQ will move your voice out of your nose.
In headphones a little cross-feed spoils the in-your-head illusion and puts sound "out there".
When you put on hearing aids (or test microphones through headphones), when you talk your own voice may sound like it is "in your nose".
Remarkably *small* adjustment of gain or EQ will move your voice out of your nose.
In headphones a little cross-feed spoils the in-your-head illusion and puts sound "out there".
Hi do you have any effective example ? and then .... out there where ? for sure not in the front of the listener.
i have never heard sound coming from the front with headphone never ever ... anyone who has tried with some kind of DSP has failed quite miserably.
That is indeed the real challenge for headphones ... front soundstage. In the best cases the sound is outside the head but always lateral ... never frontal.
The evidence is when listening to binaural recordings ... there is absolutely no sound in the front ...
I have to concede that strangely sometimes i can hear something coming from the back of my head ... and this is quite astonishing actually.
If i could get front sound i would stick happily with headphones most of the time.
Now i cannot listen to HPs for more than half an hour or so.
P.S. once listening to a youtube video i had the impression to have frontal sound ... stupid me that i have not saved the link. It was quite surprising
Maybe in the future with all this fuss on virtual reality they will acheive this. It will be a game changing day ... i love the concept of headphones.
Music is a very intimate experience ... i like listening in complete darkness ...
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I reverted back to the trusted 2 parallel resistors per Rf and Rg. Couldn't compare using the same resistors but the two resistors sounded better in my comparison. Surely the difference was due to different resistor types (Philips vs Dale).
Soon will try in Le Monstre: (1) 0.6W MRS25: Rf=10R Rg=22x10R versus (2) CMF60D: Rf=220R Rg=10R. May be Philips is just not as good as Dale, again?
i still believe that dsp is the way for a really satisfactory listening experience through headphones To find the right algorythm ? there is an immense effort to develop virtual reality systems ... even for military purposes that is what drives immense financial investments.
I am pretty sure that in the near future some kind of top gun helmet will be available also for audio video entertainment ... a virtual presence in a concert hall for instance. That feeling to be really there will be mindblowing
... From what i understand video is already at a good point ... sound is still behind ... no sounds in the front a very bad thing and huge limit ...
And of course with an excellent soundstage and quality of sound. It is just a matter of years ... 5-6 from now ?
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Yes that is right. But sometimes in some reviews i read words that makes me dream. Words like these for instance ...
Stax Lambda Nova Signature electrostatic ear-speaker Page 3 | Stereophile.com
I am sure that in the near future the way in which we listen music or watch a movie will change completely ...
i understand that the concept has been abandoned ... that must tell something
then almost all amplifiers available on the market should sound at least good. i am afraid is not the case.
Maybe a case of perverse engineering ? like they know how to design right but they instead decide to design wrong ?
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