Actually, yah. Pretty much. Sometimes it's so totally necessary.
But there are times when you need to back off a bit and let some of the others do it their way. That was a tough thing to learn for me, but the next generation needs to learn and feel confident in their actions.
My wife taught me to fight the battles that need to be fought, and decide wisely which ones not to worry about.
Jn
Resume.. I gave up on updating mine. If an interviewer has to ask me what every item on it is, I'm in the wrong place.
Sounds like few on this thread understand how utility power is produced and delivered. It's a very noisy dirty world out there. Adding injury, CE declarations on most electronics are fraudulent. (I wrote software for GE LM2500+ gas turbine cogen/peaking generators, then later ran a CE assessment lab)
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Flexible mains cables are twisted in order to aid flexibility. The twist length may be several inches.billshurv said:
Is that enough of a twist to have any benefit? If not I wonder how much an MOQ on tightly twisted 3 core is.
Coupling to external fields is reduced for wavelengths longer than the twist length.
Coupling to nearby cables requires twist lengths to not have certain ratios (such as odd integers), or nearly so.
Coupling to nearby cables requires twist lengths to not have certain ratios (such as odd integers), or nearly so.
As DF96 already mentioned it depends on the twist length; think of digital lines carrying several pairs of twisted balanced lines. Each pair twisted differently at carefully choosen ratios to minimise coupling.
In commonly used mains cables the wires aren´t twisted in that sense but bundled and sort of "curled" (means all three wires uniformly).
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hmm, so effects above 500MHz for off the shelf cable. Actually that's not too bad. Most interference sources in the home are 800MHz to 2.6GHz. Ham enthusiasts have other problems but they normally know what they are doing and don't put shakti stones on their transmitters to get more range 🙂
A belated thanks for your explanation in post #358.
I wonder if you would help aid my understanding further?
When discussing AC signals, the concept of 'return current path' must be a convenience, considering that the electrons simply oscillate in the cable.
Instead of several 'return pathways' would it be appropriate to consider there to be several 'signal transfer loops', which vary in impedance?
Either way, how does the existence of pathways or loops of different impedance affect the accuracy of signal transfer?
Frequency dependent phase alterations or signal induced back EMFs in the signal/ground loops? I need expert help! 😕
Here is a link to a YouTube video that shows Shunyata measuring power line noise with a simple device and then again with their product in use. I have seen and used the simple measuring device and although not the last word in measuring, it does display noise differences. BTW, Grant is a very nice guy to talk to.
YouTube
YouTube
Of course he will be nice, he is trying to get you to believe in his magic and part with money for something you don't need and might actually make things worse. PT Barnum and Uri Geller are from the same mould.
I thought Uri repented? The Johnny Carson thing is priceless you have to see it.
Sorry to disappoint you. No, DC does not mean steady-state. DC means that electrons are always moving through a conducting material from an electron surplus area to an electron depleted area. AC means that electrons are always moving like in DC, except that the area that was electron surplus becomes electron depleted compared to the no flow state and changes back and forth at a periodic rate.
An audio signal is, if not offset from the no electron flow reference, a variable alternating current. If offset sufficiently that the electrons don't reverse, it's a pulsating direct current.
Terminology is a bear isn't it!
Steady state means steady state ... although beyond a doubt most of the "steady state currents" we see are not really, there's always some amount of variation. Ask mister Kelvin.
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So we are in an audio forum not a voodoo forum right? Then why do some guys still believe in BS like different sound of silver vs copper conductors in a SIGNAL (!) cable driven from a low impedance output and going into a high impedance input, when there is almost no current within the cable.
Line noise? Gimme a break.. That "line noise" is rectified and poored into a big electrolytic cap to supply the electronics. While "hum" from a ground loop in an asymmetric signal transmission system like RCA may very well be a problem (that is why pro guys don t even talk about RCA connections btw.), the effect of "line noise" in audio is equivalent to the effect that a jumping fish and its waves in a river can have to the surface of a lake 20 miles downstream (with the lake fed by the river and waterfalls in between).
Line noise? Gimme a break.. That "line noise" is rectified and poored into a big electrolytic cap to supply the electronics. While "hum" from a ground loop in an asymmetric signal transmission system like RCA may very well be a problem (that is why pro guys don t even talk about RCA connections btw.), the effect of "line noise" in audio is equivalent to the effect that a jumping fish and its waves in a river can have to the surface of a lake 20 miles downstream (with the lake fed by the river and waterfalls in between).
I get confused easily. Which metal conduction theory are we working on here that needs depleted areas?
BTW it's Lord Kelvin to you 😛
+1 say it like it is, this thread and the power cable does have some comic value with a good dose of cringe worthiness.
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