john curl said:
Sorry John, looking back all these years, I don't believe you have any graphs.
Jan Didden
Calling me a liar, Jan? I will get SY over here and he can SEE the graphs. They are not secret, but they are reductions and do not reproduce well. I got them from Jack Bybee about 12 years ago, and they were done by an independent lab. They won't tell YOU much, even if you saw them, yourself.
john curl said:
I don't call anybody anything. I just said that, judging by your track record of backing up what you say, I don't believe you have graphs. Yet.
Jan Didden
john curl said:
Steve Eddy said:
Here at work we have a product that delivers 25 kva via a 3-phase Y-delta power transformer of our own design. The primary and secondary coils are adjacent rather than overlayed to minimize capacitive coupling and there is a faraday shield. The load is dynamic - not music, but dynamic. The power source for our 25 kva transformer is a 400 Hz 45 kva 3-phase generator. If I put a Tek A6303/AM503A current probe on the transformer primary phases or neutral I can see with the oscilloscope (admittedly with some distortion) all the dynamics of the secondary signal.
If we remove the generator as the source and connect a 3-phase 30 kva Invertron source that uses a 60 kHz switching supply to synthesize the 400 Hz sine waves, we can see the 60 Khz at each secondary winding of this 25 kva transformer using the current probe. This kinda tells me that the transformer does not isolate the secondary from the primary current and vice versa. There is galvanic (dc) isolation, but not ac.
The secondary is coupled to the primary capacitively and inductively - the transformer impedance ratio is the square of the turns ratio.
Those pots on the pole are taking high voltage 3-phase power and converting it to three single-phase 60 Hz sources at 120-0-120 vac. Your house ac supply may or may not be shared with your neighbor. Also whatever happens on the high voltage side, or on another low voltage pot, is reflected to some extent (it all depends on the impedances) to your house ac supply.
The pole top (or lawn top if the feeders are underground) transformers are designed for maximum efficiency. That means they don't give a fig about keeping noise or transients out of your house ac supply. The secondary of those transformers is a wide band of 1/8" aluminum, and the high voltage copper primary wire is wound directly on top of that secondary.
This is the same thing that occurs between the audio equipment power transformer primary and secondary. Anything happening inside the audio amplifier that draws primary current from the ac is effectively part of the ac line return path. There is galvanic (dc) isolation, but not ac. If you don't believe it, just look at the neutral return current in the ac power cord white wire with a current probe. You will see the audio signal at some reduced level, proportional to the impedance of the audio equipment power transformer. Likewise, the power supply design for audio equipment is very important in keeping all the crud on the ac line out of your audio signal.
I've run this test many times. It is part of the conducted emissions test for EMI qualification.
Best, Chuck Hansen
janneman said:
I went to Skywalker ranch and learned all about how THX works,
but I can't tell you because they make you sign a non-disclosure
agreement...
😎
chascode
Of course you see all AC frequencies introduced into a transformer, on all windings. The energy transform that matters in a transformer, for mains connection is at 60 Hz AC.
However, there is still direct antenna event energy transform out to RF and beyond. And there is dielectric dipole signaling across the AC / DC dielectric barriers out to RF and beyond.
The transformer doesn't care where some noise is introduced, it is going to transform it from one antenna to another, through the core for low AC frequencies, directly from antenna to antenna for higher AC frequencies and Electro statically for all sharp changes in field vector.
But, there is no direct connection between wires of opposite polarity. They are insulated from one another within the transformer for AC and DC, and in modern devices this is for voltages of up to 3500 for AC and for 5000 DC. At these voltages a certain amount of current is allowed to escape the dielectric barriers and flow over the transformer surfaces, but at mains voltages, 5 ma is the maximum or the transformer is discarded. It is outside of the transformer where grounds become common and in many cases this is the path for "noise" to be distributed through.
In your three phase device, even with a Faraday shield to eliminate the 80% or so of capacitive coupling it can block, you still have the antenna event within the core window and that is a minimum of 1000 times more intense than it is outside of the window and it is effective out past RF.
Bud
Of course you see all AC frequencies introduced into a transformer, on all windings. The energy transform that matters in a transformer, for mains connection is at 60 Hz AC.
However, there is still direct antenna event energy transform out to RF and beyond. And there is dielectric dipole signaling across the AC / DC dielectric barriers out to RF and beyond.
The transformer doesn't care where some noise is introduced, it is going to transform it from one antenna to another, through the core for low AC frequencies, directly from antenna to antenna for higher AC frequencies and Electro statically for all sharp changes in field vector.
But, there is no direct connection between wires of opposite polarity. They are insulated from one another within the transformer for AC and DC, and in modern devices this is for voltages of up to 3500 for AC and for 5000 DC. At these voltages a certain amount of current is allowed to escape the dielectric barriers and flow over the transformer surfaces, but at mains voltages, 5 ma is the maximum or the transformer is discarded. It is outside of the transformer where grounds become common and in many cases this is the path for "noise" to be distributed through.
In your three phase device, even with a Faraday shield to eliminate the 80% or so of capacitive coupling it can block, you still have the antenna event within the core window and that is a minimum of 1000 times more intense than it is outside of the window and it is effective out past RF.
Bud
Nelson,
Do you have any input on hooking signal ground to earth ground with an inductor?
Grey
Do you have any input on hooking signal ground to earth ground with an inductor?
Grey
Why is it that some people have to have an officially sanctioned theory in front of them before they will even consider something? Lightning existed for quite some time before anyone conceived of electricity as the underlying phenomenon. Did it keep lightning from happening?
Let us see...
The scene: A hilltop in Ancient Greece, a man stands alone watching an approaching thunderstorm.
Enter Practicalus, stage left, climbing the hill.
Practicalus: Ah, Skepticalus, how are you this fine afternoon?
Skepticalus: Come to waste my time with your foolish notions about lightning? You're wrong, you know. There's no substance to your musings. Lightning does not strike high places. It strikes where the gods wish it to strike.
Practicalus, shrugging agreeably: Perhaps I am wrong. Perhaps I am right. We all have to start somewhere. I would rather get it wrong by trying than get it wrong by failing to try.
Skepticalus, sneering: You and your dreamer's wishes! You have air in your head where brains should be. What is that you're carrying?
Practicalus: Some lamb wrapped in leaves from my vineyard.
Skepticalus: It's too early to eat.
Practicalus: But not too early to cook.
Skepticalus, rolling his eyes: Now what?
Practicalus: I intend to test my idea that lightning will cook food. If it is strong enough to blast a hole in the sand of the beach and create a fulgarite, surely it will cook my evening meal. After all, the microwave won't be invented for another two thousand years.
Skepticalus: You are a fool!
Practicalus: Perhaps so. If that is indeed the case, would you like to be the one to prove it?
Skepticalus: I'd like nothing better. I'm sick of your prattling about "natural phenomena." Huh! As if! You make up all these things just to annoy me. It is the will of the gods, I tell you! I am quite safe standing here because I have done nothing to anger the gods. You, on the other hand...
Practicalus: Then if you don't mind, take my lamb and hold it above your head...thus. Excellent! Now, if you don't mind my doing so, I'll just step away and observe from a little ways down the hill. If the lightning strikes me, you will have the last laugh.
Practicalus retreats. The storm gathers strength. Lightning comes closer, then closer still...then, finally, a massive bolt smites the hilltop. Practicalus waits for the storm to abate before ascending the hill. He approaches Skepticus.
Practicalus: Poor Skepticalus, here you stand, turned to charcoal, but this cloud did indeed have a silver lining...I see that my lamb is cooked. Let's see...sadly, it turned out well-done. I would have preferred medium, but we can't have everything we want in life, can we?
As Practicalus descends the hill, he can be heard to say: Of course, I still don't know whether the lightning striking Skepticalus was the will of the gods or simply because he was the highest point on the hill, but I do have this excellent meal to nourish me while I ponder the problem.
Exit Practicalus, stage left.
Grey
Let us see...
The scene: A hilltop in Ancient Greece, a man stands alone watching an approaching thunderstorm.
Enter Practicalus, stage left, climbing the hill.
Practicalus: Ah, Skepticalus, how are you this fine afternoon?
Skepticalus: Come to waste my time with your foolish notions about lightning? You're wrong, you know. There's no substance to your musings. Lightning does not strike high places. It strikes where the gods wish it to strike.
Practicalus, shrugging agreeably: Perhaps I am wrong. Perhaps I am right. We all have to start somewhere. I would rather get it wrong by trying than get it wrong by failing to try.
Skepticalus, sneering: You and your dreamer's wishes! You have air in your head where brains should be. What is that you're carrying?
Practicalus: Some lamb wrapped in leaves from my vineyard.
Skepticalus: It's too early to eat.
Practicalus: But not too early to cook.
Skepticalus, rolling his eyes: Now what?
Practicalus: I intend to test my idea that lightning will cook food. If it is strong enough to blast a hole in the sand of the beach and create a fulgarite, surely it will cook my evening meal. After all, the microwave won't be invented for another two thousand years.
Skepticalus: You are a fool!
Practicalus: Perhaps so. If that is indeed the case, would you like to be the one to prove it?
Skepticalus: I'd like nothing better. I'm sick of your prattling about "natural phenomena." Huh! As if! You make up all these things just to annoy me. It is the will of the gods, I tell you! I am quite safe standing here because I have done nothing to anger the gods. You, on the other hand...
Practicalus: Then if you don't mind, take my lamb and hold it above your head...thus. Excellent! Now, if you don't mind my doing so, I'll just step away and observe from a little ways down the hill. If the lightning strikes me, you will have the last laugh.
Practicalus retreats. The storm gathers strength. Lightning comes closer, then closer still...then, finally, a massive bolt smites the hilltop. Practicalus waits for the storm to abate before ascending the hill. He approaches Skepticus.
Practicalus: Poor Skepticalus, here you stand, turned to charcoal, but this cloud did indeed have a silver lining...I see that my lamb is cooked. Let's see...sadly, it turned out well-done. I would have preferred medium, but we can't have everything we want in life, can we?
As Practicalus descends the hill, he can be heard to say: Of course, I still don't know whether the lightning striking Skepticalus was the will of the gods or simply because he was the highest point on the hill, but I do have this excellent meal to nourish me while I ponder the problem.
Exit Practicalus, stage left.
Grey
GRollins said:
Well to me causality, conservation of charge, and conservation of energy are intuitive in the primitive sense you know like I'm a kid and observe cause and effect. Your mileage may vary of course.
Scott,
Ah, but you're still assuming that the Greeks knew what cause and effect were in the case of lightning. They didn't. And neither did the Romans, the Saxons, the Druids, the Mongols, the Vikings, nor the Cossacks. That didn't stop them from acknowledging that lightning existed. Of course, a lot of utter hogwash was uttered over the centuries as people attempted to explain what lightning was and what caused it. The Greeks thought cause and effect were explained by invoking Zeus's wrath. Did that make it right? Of course not. But did lightning cease to exist simply because they had their explanation wrong? Of course not.
To this day, we still don't know everything there is to know about lightning. People launch rockets trailing wires into clouds in an attempt to get lightning to strike in front of test instruments. We're still learning things about lightning.
Odd effects exist. To say that absolutely everything is known about any given subject is the height of arrogance. Physics was quite famously declared to be 'done,' and people believed it to be so. Of course, that was right before the bottom fell out and Newtonian physics got shouldered aside by these little itty-bitty particles that no one had thought possible previously. And we're still learning things. Sometimes the discoveries were predicted ahead of time and the experimental results merely served as confirmation. Sometimes the predictions didn't work out. Sometimes serendipity intervened and the experimenter said, "That's funny..." in the best Asimovian sense.
Are there undiscovered distortion mechanisms in audio? I'd have to say yes. Are there counterintuitive things going on in audio? Definitely. After all, caps were proven to be different from one another. That certainly set some people back on their haunches. Absolute phase was proven to be audible. And along the way a lot of strands of spaghetti got thrown against the wall that didn't stick. Does that in any way invalidate the strands that did stick? No.
Oh, and Snagglepuss? He caught up with Practicalus just as he got to the bottom of the hill. They went into town, bought a bottle of wine, and spent the evening discussing the origin of species. They were laughed at, mocked, and criticized by their contemporaries...no surprise, I guess.
Grey
Ah, but you're still assuming that the Greeks knew what cause and effect were in the case of lightning. They didn't. And neither did the Romans, the Saxons, the Druids, the Mongols, the Vikings, nor the Cossacks. That didn't stop them from acknowledging that lightning existed. Of course, a lot of utter hogwash was uttered over the centuries as people attempted to explain what lightning was and what caused it. The Greeks thought cause and effect were explained by invoking Zeus's wrath. Did that make it right? Of course not. But did lightning cease to exist simply because they had their explanation wrong? Of course not.
To this day, we still don't know everything there is to know about lightning. People launch rockets trailing wires into clouds in an attempt to get lightning to strike in front of test instruments. We're still learning things about lightning.
Odd effects exist. To say that absolutely everything is known about any given subject is the height of arrogance. Physics was quite famously declared to be 'done,' and people believed it to be so. Of course, that was right before the bottom fell out and Newtonian physics got shouldered aside by these little itty-bitty particles that no one had thought possible previously. And we're still learning things. Sometimes the discoveries were predicted ahead of time and the experimental results merely served as confirmation. Sometimes the predictions didn't work out. Sometimes serendipity intervened and the experimenter said, "That's funny..." in the best Asimovian sense.
Are there undiscovered distortion mechanisms in audio? I'd have to say yes. Are there counterintuitive things going on in audio? Definitely. After all, caps were proven to be different from one another. That certainly set some people back on their haunches. Absolute phase was proven to be audible. And along the way a lot of strands of spaghetti got thrown against the wall that didn't stick. Does that in any way invalidate the strands that did stick? No.
Oh, and Snagglepuss? He caught up with Practicalus just as he got to the bottom of the hill. They went into town, bought a bottle of wine, and spent the evening discussing the origin of species. They were laughed at, mocked, and criticized by their contemporaries...no surprise, I guess.
Grey
I wonder if all quality IC's are the same also? Some cost more than others, but is it really worth paying a premium, when another manufacturer can sell something a few dollars cheaper? What would I look for? Scott, any answers?
When I made classD, there is one interesting test. To look at the response of the amp openloop, put square wave, and see how much delay and what is the shape of the output without global feedback.
Opamps (voltage feedback) are lousy in this test. They delay alot, and the shape of the squarewave distort alot. Simple discrete design is better in this test, also the delay is less.
Is this indicating something, towards perceived sonics?
Opamps (voltage feedback) are lousy in this test. They delay alot, and the shape of the squarewave distort alot. Simple discrete design is better in this test, also the delay is less.
Is this indicating something, towards perceived sonics?
Oxner JFET book
I found "Designing with Field-Effect-Transistors, 2nd Edition" by Ed Oxner on Amazon as a hard cover used book. It arrived in very good condition, only minor cover wear. The supplier was Piedmont Books. Only one was listed on Amazon at the time, but I see 4 more are listed right now.
Best, Chuck Hansen
I found "Designing with Field-Effect-Transistors, 2nd Edition" by Ed Oxner on Amazon as a hard cover used book. It arrived in very good condition, only minor cover wear. The supplier was Piedmont Books. Only one was listed on Amazon at the time, but I see 4 more are listed right now.
Best, Chuck Hansen
Hog-out Aluminum Chassis
Perhaps John, Charles and/or Nelson might be interested in this. We had a recent program where we used an aluminum chassis machined from a solid block (much like the Blowtorch chassis). It has an integral 19" rack front plate, and heat sink finning on the bottom. It was about twice the cost of John's Blowtorch chassis. We decided to get a quote for a casting. It turned out to be just $1800, with all the added machining and tapped holes. Break-even quantity after paying for the tooling was only 22 castings. The casting vendor was Armstrong. I'll try to find out the alloys used, but there are definitely "aircraft aluminum".
Best, Chuck Hansen
Perhaps John, Charles and/or Nelson might be interested in this. We had a recent program where we used an aluminum chassis machined from a solid block (much like the Blowtorch chassis). It has an integral 19" rack front plate, and heat sink finning on the bottom. It was about twice the cost of John's Blowtorch chassis. We decided to get a quote for a casting. It turned out to be just $1800, with all the added machining and tapped holes. Break-even quantity after paying for the tooling was only 22 castings. The casting vendor was Armstrong. I'll try to find out the alloys used, but there are definitely "aircraft aluminum".
Best, Chuck Hansen
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