Charles Hansen said:
Charles, to some degree I blame it on the times. Not that there aren't foolish people in every era, but we happen to live in one in which, for instance, people deny the toxicity of lead and mercury. I happen to have the unfortunate distinction of living in one of the most poorly educated states in the nation. A state where people routinely say daft things like, "There's no such thing as global warming." Why do they say that? Because their masters told them it's so. And why do their masters say that?
Get this...
Because it's snowing in New York where their studio is!
Now, you'd think that anyone who devoted even an instant's thought to the matter would realize that it can snow at 20 degrees and also at 25 degrees, and that 25 degrees is warmer than 20 degrees and that it might just be significant...but no. Clearly it's cold when it's snowing and therefore if it's cold, there's no such thing as global warming.
Heavy metals aren't toxic. Those symptoms that show up years later are due to something else. Something completely unrelated to the removal of mountain tops whilst mining coal that releases arsenic and such into the water table. Obviously.
A rather blatant disconnect from reality, in other words.
And, as you say, if they'd only put a moment's actual thought into the matter, they might figure out how it could be so. Only they'd rather expend ten times the energy mocking those who say things they're too lazy to consider for themselves.
The self-righteous, self-aggrandizing attitude is all too familiar. I am surrounded by it every day.
Grey
What was that all about? Do we have to put up with another lead-fanatic? We already have 3rd wire fanatics here as well. Many of us have lots of experience with lead solder, bad words, lead in gasoline, mercury, etc. We are still here, and OK given our age and past experiences.
Many of us lived 1/2 our lives without 3rd wire systems, and lived through it. We don't want to hurt anyone, or have anyone hurt themselves using our equipment. However, we also know when too much concern is put forth, such as Bobken lead poisoning school children if he gave his older electronic parts to the school.
Many of us lived 1/2 our lives without 3rd wire systems, and lived through it. We don't want to hurt anyone, or have anyone hurt themselves using our equipment. However, we also know when too much concern is put forth, such as Bobken lead poisoning school children if he gave his older electronic parts to the school.
syn08 said:
I think they consider me unmutual.
John, plenty of folks are happy with that part (it's not mine BTW). You told me that you and Dave Wilson listened to about a dozen op-amps in his crossovers and the 741 came in around third. So what on earth does high order harmonics have to do with anything.
I read further on the degaussing of LP's. They had actual measurements. An LP has residual magnetism of about .1% of the earths magnetic field and their device removes 10% of that (which seems strange).
Hi John,
If you are using it as an integrator for DC offset control, put a resistor in series with the integration capacitor and limit the input range so it doesn't clip. Filtering the resulting output further should remove any "sound" the op amp has.
Then of course comes the first question. Why are you using the op amp, and do you need that much gain? Could you not perform the same function with a few transistors?
I'm sorry I can't suggest anything more intelligent. The person you ought to be talking to would be Walt Jung, wouldn't you agree? You do know the man reasonably well don't you? I am assuming that you've talked to Scott Wurcer. Those guys are light years ahead of anything I would know. Heck, most everything I know about using op amps I learned form Walt Jung and app notes.
-Chris
Yes, it is a legal concern but also a safety issue. After spending so many years in service, the third wire does save people from shocks and destruction of equipment due to bad technicians, home fix-it and lousy manufacturing. Sadly, we really do need a three wire system. As SY can tell you, I do run some two wire, old equipment as well.
John, we are not disagreeing here at all. In fact I think we agree more than we disagree on things. You are an excellent example of what I call a good engineer. You measure, you listen and you improve the design. So, where's the fire?
Sorry, I'm not familiar with the AD825, never seen one. So aside from making sure the supplies are well bypassed to your "dirty" ground, and making sure the output load is within reasonable limits for that chip, I can't even begin to say. I don't even know your application.
If you are using it as an integrator for DC offset control, put a resistor in series with the integration capacitor and limit the input range so it doesn't clip. Filtering the resulting output further should remove any "sound" the op amp has.
Then of course comes the first question. Why are you using the op amp, and do you need that much gain? Could you not perform the same function with a few transistors?
I'm sorry I can't suggest anything more intelligent. The person you ought to be talking to would be Walt Jung, wouldn't you agree? You do know the man reasonably well don't you? I am assuming that you've talked to Scott Wurcer. Those guys are light years ahead of anything I would know. Heck, most everything I know about using op amps I learned form Walt Jung and app notes.
-Chris
Hi Grey,
When people design by using their instruments, they are usually properly trained and actually pay attention to the circuit design. They know how to stay within the safe bounds of operation for the parts. Any high distortion readings generally point to an error in the circuit where some component is not operating in it's linear range. I have seen this time and time again over many years. People who design only by ear generally do not pay close attention to the operating points on their active devices. They are more concerned with getting "that" sound or using "that" part or wire. Most often, those designs are not stable and prone to failure.
Now, since you don't know me. I was authorized warranty for McIntosh and many other high end brands, some designed by ear only. I do have a lot of experience there. Also, modifications for better sound done by others that ended with circuit failure. Again, design by ear people.
Old tube stuff eh? I enjoy restoring old radios from the 20's and up. Restoring old sound equipment and restoring test equipment. I am pretty certain that I can differentiate between well made things that last (as in durable goods) and stuff that doesn't generally last a long time.
What I want to know is what set you off. I didn't pick a fight with you. I just thought that you made a comment that really got the measure vs listen fight going. Most people here do measure and listen, so your comment may have targeted a very small group of people. My further comments expanded on that.
If you saw an attack or insult there, it certainly wasn't intended.
-Chris
What are you talking about? What do you think I meant anyway?
When people design by using their instruments, they are usually properly trained and actually pay attention to the circuit design. They know how to stay within the safe bounds of operation for the parts. Any high distortion readings generally point to an error in the circuit where some component is not operating in it's linear range. I have seen this time and time again over many years. People who design only by ear generally do not pay close attention to the operating points on their active devices. They are more concerned with getting "that" sound or using "that" part or wire. Most often, those designs are not stable and prone to failure.
Now, since you don't know me. I was authorized warranty for McIntosh and many other high end brands, some designed by ear only. I do have a lot of experience there. Also, modifications for better sound done by others that ended with circuit failure. Again, design by ear people.
Old tube stuff eh? I enjoy restoring old radios from the 20's and up. Restoring old sound equipment and restoring test equipment. I am pretty certain that I can differentiate between well made things that last (as in durable goods) and stuff that doesn't generally last a long time.
What I want to know is what set you off. I didn't pick a fight with you. I just thought that you made a comment that really got the measure vs listen fight going. Most people here do measure and listen, so your comment may have targeted a very small group of people. My further comments expanded on that.
If you saw an attack or insult there, it certainly wasn't intended.
-Chris
I am using HP lab power supplies. My own designs with the same supplies don't have much of a problem, only these IC's, the AD817 and AD825. The actual design is a little more complicated than just the IC, but testing with just the IC gives essentially the same results.
What I look for mostly, is 5th, 7th, and 9th harmonic. I can live with just about anything else.
What I look for mostly, is 5th, 7th, and 9th harmonic. I can live with just about anything else.
Hi John,
I use HP supplies also, 6236 and 6237 mostly. Nice little supplies (and really old).
John, I wish I could help you and I don't know that I even can. If you want, PM me some details and I'll have a look. I will sign an NDA if you feel it's that sensitive, and you have my word nothing goes any further.
I am in no position to manufacture or market anything either.
-Chris
Edit: I'm hitting the sack now. It's almost 1:00 AM here.
Have a good night.
I use HP supplies also, 6236 and 6237 mostly. Nice little supplies (and really old).
John, I wish I could help you and I don't know that I even can. If you want, PM me some details and I'll have a look. I will sign an NDA if you feel it's that sensitive, and you have my word nothing goes any further.
I am in no position to manufacture or market anything either.
-Chris
Edit: I'm hitting the sack now. It's almost 1:00 AM here.
Have a good night.
Chris, I am now mostly directing this at Scott Wurcer. He knows who designed these products and he has not yet told me who the person is. He might have been able to help me understand what I am measuring, better, but I don't think I will get much at this point. Personally, I doubt that anything can be done about it. Design, discrete fet, is the only solution that I know well. Just trying, (one more time) to use IC's in audio products.
Charles,
IMO it is useless to try to persuade everyone. Words cannot transfer real experience.
Everyone who has ever seriously worked with audio knows problems of interference currents caused by capacitive coupling through PSU transformers and knows that these currents depend on AC cord connector position, as the real world coupling differs then.
Those who have no real experience and rely only on their simulators (which is fine, but models are usually incomplete) would not believe you. They only demonstrate how poor are they even in simulations, because these issues can be modelled as well.
So, better keep cool and not waste time with ignorants.
Regards,
Pavel
IMO it is useless to try to persuade everyone. Words cannot transfer real experience.
Everyone who has ever seriously worked with audio knows problems of interference currents caused by capacitive coupling through PSU transformers and knows that these currents depend on AC cord connector position, as the real world coupling differs then.
Those who have no real experience and rely only on their simulators (which is fine, but models are usually incomplete) would not believe you. They only demonstrate how poor are they even in simulations, because these issues can be modelled as well.
So, better keep cool and not waste time with ignorants.
Regards,
Pavel
Bobken said:
The primaries of an R-core are wound on both bobbins, but in different directions in comparison to the primary winding of a toroidal.
A picture i posted of R-cores i rewinded for lower output voltages some time ago here
(i assuggested becoming fundamental Mormons without the reli routine, but my G/F didn't go for it)
anatech [/i][B] I don't believe the phasing of power transformers should make any difference said:
and
anatech said:
As far as I remember, no one in this thread spoke about designing by the ear only. John Curl stated here again and again that first he measures his products and then he listens to it, or asks others to listen to it. It seems that the same applies to other designers who participate here, who also listen to their products.
The basic design must be measured and is measured.
However, there are some issues that follow the basic design, like choosing capacitors, resistors, switches and wires. Here listening tests are predominant.
So, the argument isn't between those who design by ears alone versus those who design by measuring. The argument is between those who design by first measuring and then listening, versus those who design by measuring alone.
So, what is you stand in THIS argument?
At least this thread is entertaining when its not educating. We have some real prima-donna's here. Wonderful stuff.
But, getting back to physics, can someone explain why doing this
Quote
Raise all of the cables off the floor with wood blocks.
Unquote
improves the sound. I've seen this in high end magazines and you can even buy special blocks for this purpose.
What does it do physically - lower the system capacitive coupling to the ground (but maybe if you have X and Y caps installed on the mains side this is not an issue? Or, maybe you have a solid earth anyway?)
But, getting back to physics, can someone explain why doing this
Quote
Raise all of the cables off the floor with wood blocks.
Unquote
improves the sound. I've seen this in high end magazines and you can even buy special blocks for this purpose.
What does it do physically - lower the system capacitive coupling to the ground (but maybe if you have X and Y caps installed on the mains side this is not an issue? Or, maybe you have a solid earth anyway?)
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