Thats good Pavel.
Feeding back the current distortion, in the way i showed, reduced the THD from the driver output.
We have two ways now..... How many other ways can this current distortion be used to reduce driver's output THD?
THx-RNMarsh
Feeding back the current distortion, in the way i showed, reduced the THD from the driver output.
We have two ways now..... How many other ways can this current distortion be used to reduce driver's output THD?
THx-RNMarsh
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I saw Joe pinned down to consistent current vs frequency in an amp, where a reactive load was not invited into the feedback loop so the amp behaved better. Has it changed to driver THD?
How will this circuit distinguish between current changes caused by distortion and by (needed) frequency dividing?? It is impossible to use it with passive crosover.. And I feel here a big risk of low frequency unstability (big phase shifts in feedback). Some results from practical aplications?
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This remains irrelevant to the discussion here, PMA is trying to address some very wrong statements about how amplifiers work. Please don't distract from that, some here of less experience might learn something. Continuing to discuss something that Joe is not talking about and which has had plenty of discussion elsewhere could only be interpreted as some kind of agenda. No comment.
Thank you Scott, this is exactly my goal. And it took some time to prepare and make some meaningful measurements.
As someone of less experience and being on the outside looking in I find the behavior here quite interesting, does it really matter?
People are inclined to believe and try whatever they want, y’all with the fud and the trolls why not step back and take a listen instead of a measurement?
Many technological advancements are made by accident or wrong doing.....pushing the envelope.
I applaud the likes of Richard, joe , jc , mark, merril, and even dan!
People are inclined to believe and try whatever they want, y’all with the fud and the trolls why not step back and take a listen instead of a measurement?
Many technological advancements are made by accident or wrong doing.....pushing the envelope.
I applaud the likes of Richard, joe , jc , mark, merril, and even dan!
First, how do you know we are not listening?
Second, if you listen and find something, do you want to understand why or it is not the case and you tend to believe what you read in popular magazines? I am in the camp of those who want to know "why", because it is the only way how not to go on a trial/error path and not knowing why there is an error. And to know why means you have to study first and and then to make an experiment and to measure. The idea that a circuit designer is something like a painter and that electronics is similar to art is wrong from the beginning.
BTW, we may differ whom we consider to be a Troll.
Some who may or may not be trolls themselves, if you met them in a different setting 😡
Well I do see a lot of simulation and test tones, dummy loads etc......but hardly ever see it then correlated to actual musical reproduction?
I would like to know why I (and others) can hear things we’re not supposed to? And it’s not because someone planted the seed.....it’s because I heard a difference and dug until I found an explanation. Explanations that are then relegated to the ‘fud’ bin.
I would like to know why I (and others) can hear things we’re not supposed to? And it’s not because someone planted the seed.....it’s because I heard a difference and dug until I found an explanation. Explanations that are then relegated to the ‘fud’ bin.
Hi Bob,
Every good designer / engineer I know does both. They measure and listen. Some of the worst designs ever are the result of designing by ear. Some of the least involving stuff marketed has been designed by measurements only. You're on the right track when they both agree. In the end, it is understood that people will just listen, but to make sure you are giving them their money's worth, measurements must be part of the process.
As mentioned above, our instruments are far better than they were in the 1980's. So many of us learned at a time when we couldn't measure the important stuff. However, in 2019 everything has changed and we can take meaningful measurements well past our ability to hear any difference. Of course, some people are better at interpreting the test results than others.
-Chris
Every good designer / engineer I know does both. They measure and listen. Some of the worst designs ever are the result of designing by ear. Some of the least involving stuff marketed has been designed by measurements only. You're on the right track when they both agree. In the end, it is understood that people will just listen, but to make sure you are giving them their money's worth, measurements must be part of the process.
As mentioned above, our instruments are far better than they were in the 1980's. So many of us learned at a time when we couldn't measure the important stuff. However, in 2019 everything has changed and we can take meaningful measurements well past our ability to hear any difference. Of course, some people are better at interpreting the test results than others.
Not anymore! The instances of this might be way over-reported. Generally, advances were made using math or testing a hypothesis. Also, generally speaking these things are advanced by more than one person in a team of people. The image of someone discovering anything by mistake in a garage is ancient history. Now it is teams and a lab with nice equipment, and a listening room. The garage stereotype is long dead.
-Chris
Hey there Chris,
Yah I get all that, but I also believe shutting the garage door definately stops the possibility.
And it still doesn’t explain how all this modern equipment says there’s no differences in ‘this’ vs ‘that’ when it’s quite obvious (at least to me) there is?
Yah I get all that, but I also believe shutting the garage door definately stops the possibility.
And it still doesn’t explain how all this modern equipment says there’s no differences in ‘this’ vs ‘that’ when it’s quite obvious (at least to me) there is?
One definition of internet trolling:
Internet troll - Wikipedia
Off topic chat has not been a problem here in the past, for the most part. There has been an uptick in certain types of trolling behaviors in the thread more recently. Jakob described it using the term 'bullying' which may be more to the point of recent issues vs the more general term, trolling.
Internet troll - Wikipedia
Off topic chat has not been a problem here in the past, for the most part. There has been an uptick in certain types of trolling behaviors in the thread more recently. Jakob described it using the term 'bullying' which may be more to the point of recent issues vs the more general term, trolling.
"As the pot calls the kettle black" is an old saying.
Listening is why we get out the test equipment to see what is going on. I don't know of any serious amateur or professional who does not listen.
There have been quite embarrassing results from products produced by measurement over riding all else. Of course there are also lots of bad examples of done entirely by ear.
It used to be even the basic test equipment was quite expensive. Today computers are almost universal and even if you buy a used one and a new interface you can do very good measurements for a few hundred dollars.
When I started doing large projects the minimum required test equipment ran about $10,000 and distortion analyzers were not included.
I do have more than $100,000 worth of test equipment but only a quarter of that was bought new.
RNM and Demian have collected even more test equipment than me!
Listening is why we get out the test equipment to see what is going on. I don't know of any serious amateur or professional who does not listen.
There have been quite embarrassing results from products produced by measurement over riding all else. Of course there are also lots of bad examples of done entirely by ear.
It used to be even the basic test equipment was quite expensive. Today computers are almost universal and even if you buy a used one and a new interface you can do very good measurements for a few hundred dollars.
When I started doing large projects the minimum required test equipment ran about $10,000 and distortion analyzers were not included.
I do have more than $100,000 worth of test equipment but only a quarter of that was bought new.
RNM and Demian have collected even more test equipment than me!
@mmb
Once you advance one part of a system beyond the sum of all information on this forum, the differences can become easier to discern by ear, but there can be many layers standing in the way before that is possible.
Once you advance one part of a system beyond the sum of all information on this forum, the differences can become easier to discern by ear, but there can be many layers standing in the way before that is possible.
Hi again Bob,
The correlation to actual musical reproduction is what the interpretation of tests is all about. It is possible to predict the average response to a design when judged by lay people. I do improvements to some equipment that is measurable and repeatable, as well as audible. If I couldn't do that, I would have to advertise and be a snake oil salesman.
The reason we use standard tests with standard loads is so that other normally (properly) equipped labs or service benches can replicate our work, or confirm our results on a piece of equipment. If you don't have any standard tests, how could you possible "know where you are" in a design sense.
For a number of years I made do with equipment that didn't show the actual performance I was getting. I was lucky enough to have participated in the group buy for the RTX-6001 (do a search) which allowed me to "see" what the response to changes were. That instrument allowed me to improve upon what I do.
-Chris
Certainly there is a lot about the measurement process that you can't understand because you aren't in that field. The same as if I wanted to build a boat or house. These things are a mystery for me as far as details go. I imagine what you do well wouldn't be clear to me either.
The correlation to actual musical reproduction is what the interpretation of tests is all about. It is possible to predict the average response to a design when judged by lay people. I do improvements to some equipment that is measurable and repeatable, as well as audible. If I couldn't do that, I would have to advertise and be a snake oil salesman.
The reason we use standard tests with standard loads is so that other normally (properly) equipped labs or service benches can replicate our work, or confirm our results on a piece of equipment. If you don't have any standard tests, how could you possible "know where you are" in a design sense.
For a number of years I made do with equipment that didn't show the actual performance I was getting. I was lucky enough to have participated in the group buy for the RTX-6001 (do a search) which allowed me to "see" what the response to changes were. That instrument allowed me to improve upon what I do.
-Chris
Hi Ed,
-Chris
Completely agree!! In fact, it still is. When my bench meter went down I had to sell some of my stuff in order to replace it. It was about $1,800 CDN I think
-Chris
Isn't Pavel showing the current distortion caused by the varying load impedance? I'm confused by Richard's comments, is that the point?
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