What you touch on is actually a huge problem in the domain I enjoy employment in. I am never called in to solve problems that reside in one discipline. I work in a place where a large percentage of the people are world leading experts, but not in multiple disciplines. Problems we call "hybrid problems", and the ability to solve such crossovers is difficult to pass on to the next generation.
Understanding code for example (NEC), many are good at that. Many are good at EMC/EMI. But typically, large organizations do not allow anybody to become fluent in both, considering the disciplines independent**. Code doesn't care about interference between systems, just the integrity of the wiring systems and safety of the systems. For example, bonding all the equipment to a common ground is the safe thing to do, but that many times causes stray currents that will disturb delicate systems. The end users have to worry about the final product, not code.
Every single cable tray, conduit, and rack we use is bonded using a continuous 2/0 stranded bare copper wire, yet one problem we encountered was a tray to conduit arc of about an inch length. It was caused by stray currents due to a load to ground capacitance on a 5kA pulse load. Code didn't inform us (2005) for things like this, it is getting better.
Teaching this stuff for decades, giving talks and tours, it really gets easier to determine the level of expertise by what they say and by what they ask. I'm sure many have experienced detailing something to another, then they ask a question that tells you they don't get it.. Doesn't mean they are stupid.
For example, being told to keep AC power cords away from unbalanced line level cables, and cross them at 90 degrees..??? That tells me the person des not understand EMC/EMI, but rather that they are repeating what they learned from others. I run a mixing rack 100 feet away from the power amp rack, and wrapped the line level cables around the AC power cord to solve a noise issue.
Saying that power cord geometry/construction is not important is another tell, especially with systems that are bonded and interconnect using unbalanced signals.
And again, stating that someone does not have a specific level of expertise is not putting them down. Saying a brain surgeon doesn't have a high level of EMI understanding is not a put down.
You are intent on finding fault rather than discuss the topic, a very common online occurrence.
John
** I needed to detail this a little more. In my employ, I was the sole person responsible for the entire wiring system on the scientific side of the machine, the wire "czar" as it were. Everything from femptosecond stable cabling to 535 kcmil singles to inch diameter heliax. At other facilities, they are giving code responsibility to multiple people in multiple groups. And they don't cross-communicate well. The result is total anarchy, and they will have huge system interference problems because of that. They could mitigate this if they met weekly to discuss, but everybody is too busy to do that.
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But yet, you have no problem linking youtube videos and presenting them as tell-alls that should not be questioned, a source of absolute information..
And when they are questioned, you attack the questioner.
Again, common internet forum behaviour.
john
As Jan said, worth repeating, you cannot prove a negative.
ABX tests are really hard to do properly, take very large sample sizes, and if they do not show a difference are only valid to the specfic test/listener. When they do confirm the hypothesis, it is a strong result.
So no, they have not proven that cables make no difference. That you believe they do shows a significant lack in your understanding of the limits of ABX.
dave
Interesting, a good friend is a master stained-glss artist. Do show us a pic when done.
dave
Anycubic photon M3, the basic starter kit and fairly cheap.
Here are two of my builds. the window is 29 inches diameter. Tweety still needs eyes, eyebrows, and fingers.
My centerpiece was just to learn, but I'm not happy with just 2-D glass, so I have refurbed a glass kiln, installed a K type thermocouple, and will build an arduino control for ramp, dwell, and cooldown profiles. the intent is to make forms using vermiculite board that I can slump the glass over. I plan on making another centerpiece but with the glass spiraling around the center axis, first ccw then cw halfway up. A work in progress, both in design and seeing what the colors do through the firing. Not sure if I have to worry about the COE of the glass or the cooldown rate.
My wooden gear clock pendulum is behind the piece, and the brass weights are in front. I made the top and bottom caps using my lathe, soldered them onto the brass shells. Had to do some PM on the clock, been running for 5 years now and the wood teeth needed polishing.
John
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:^)
Ceratinly shows more talent than in my one and only stained-glass effort.
You might want to email me, (if you have time), i am sure that you can learn from Buzz, and i think he may be very interested in your glass-making, he is bemoaning the disapearance of quality glass, he is particualrily unhappy that Spectrum closed down.
dave
Ceratinly shows more talent than in my one and only stained-glass effort.
You might want to email me, (if you have time), i am sure that you can learn from Buzz, and i think he may be very interested in your glass-making, he is bemoaning the disapearance of quality glass, he is particualrily unhappy that Spectrum closed down.
dave
I attack the questioner when he consistently and repeatedly brags about he is so much smarter than everyone else. And puts down people with engineering degrees as considerably less knowledgeable than he is without one.
I haven't bragged about being smarter than everyone else, so stating it multiple times makes it no more valid.
You confuse intelligence with experience.
John
I'm not sure it's talent. It is most certainly patience. This go around I decided to get the right tools. I have a Taurus ring saw (diamond coated band saw that goes through glass really well), a grinding setup, and a 6 by 2 foot light table. Oh, and a good supply of band aids..
And I use my CNC laser to inscribe my initials at the bottom of each piece.
John
Sigh. Let me show you a picture of where John works*. He's a proper capital 'E' EE. It's very very safe to say he's good with wires. You on the other hand so far have shown about as much knowledge on wire as one would pick up from reading hifi mags and the odd youtube video. They don't tend to talk about Kirchhoff's law very often in stereophile, but that is exactly what John has been trying to explain to you in his own way. If you understand Kirchhoff's law then you can look at the pictures George posted the link to and see if the light bulb goes off. Otherwise no progress is likely to be made.
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I can assure you that I fully understand Kirchoff's law, as well as those of Faraday, Ampere, and Lenz. All studied and well understood as part of an Electrical Engineering curriculum at a major university.
My problem with John is how he put down other people in some of his earlier posts in this thread as not being as knowledgeable as he claims to be.
Sorry Bill, just had to....
U/S cleaner on left, grinder next, ring saw right, glass storage on shelves.
3D printed fan holder, grinder bit holder, copper tape holder/dispenser, tool holder, and soldering station.
Handles on left drawers 3d printed. Resistor color coded of course.
Laser cnc on bottom right of pic. Didn't have the resin printer when photo taken.
Antique clock repair station just barely visible, electronics bench out of frame on right, with stereoscope there in case I have to solder any of those infernal god forsaken surface mount chips..
John
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And yet you were unable to apply it to the example of a ground loop with a simple two path frequency dependent setup.
While there may be some who would say you obviously didn't learn what you claim you studied or are stupid, I am not one of them.
You did not learn EMC theory and practice, simple as that.
Doesn't mean your stupid, or less intelligent than others, just means you didn't learn it.
And the reason is, it is a fledging engineering discipline, being formulated over the last decade or so.
John
Given your terribly misconstrued defense of Gene, I'm wondering if there is something you are not telling us?
From my limited understanding, few, if any, have completely figured out Faraday. There is some reall deep stuff that eludes most.
dave
Looks like a circular horse-barn. We got one up the road here.a picture of where John work