Stop making my head explode!
Good God man, that needs to be carved in stone around here somewhere. That is the crux of the biscuit, right there.
I've said it before:* The less I trust my ears, the better my stereo sounds. Seriously. It takes a hell of a lot more time and effort to approach it that way, but it has paid off well beyond my expectations. Plus, I've learned stuff.
-- Jim
*Sorry, but I've only ever said maybe 2 or 3 clever things, so I have to repeat myself a lot.
The first paragraph is worth understanding - NEC code doesn't specify performance of the earthing connection, just a minimum standard.
Some bonehead electrician decided to drive a ground rod through some telecom cables at a former job. I have no idea why, as the rod was not connected to anything.... I decided to measure his "ground" (mostly surrounded by paving) using the clamp-style meter we had, using the nearby portable generator connection as the "reference" and a bit of cat5 as a conductor. It measured in the hundreds of ohms. Adding another ground rod wouldn't have made it much better.
The second paragraph is also worth understanding - the important phrase on that one is "obscure path".
A friend told me of a local hospital that had two buildings connected by a skyway. For some install they had used a telecom room in one to feed the other building. The buildings had different ground rods. The system had issues and eventually it was found that there was a current of several amps flowing along those cat 5 cables...due to the potential difference between the earthing points. If there had been a lightning strike nearby (big potential difference) there could have been a huge fire.
Have you ever flown in the left seat, or piloted in the right? Audio on aircraft ... and I mean ALL aircraft ... is horrible. Full Stop.
Now, I don't attribute that to a lack of earth grounding, but as an example, you picked possibly the very poorest one out there. If it's gas powered, they even shield the spark plug wires, and no, it doesn't seem to help.
The same principle, if I understand you correctly, could be illustrated if you used an automobile as an example. At least you can get something to sound reasonably good in a car.
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But it works and always works. It doesn't crackle when they turn the coffee machine on or cause the entertainment screens to go fuzzy when the pilot transmits etc. The EMC/EMI is taken very seriously. Sound quality is not a concern, intelligibility however is. So a very very good example.
Firewalling is however something they have taken a while to understand.
Its an excellent illustration of shielding with no PE connection...
No the lack of earth grounding has NOTHING to do with it
PE (protective earth/Ground) is there for safety reasons nothing else....
Interesting. I thought that most CAT5 and Ethernet connections were differential with no ground reference. Were the ports of the switches and routers on both ends tied to earth?
I didnt think 24 gauge wire could have several amps without breaking down. I could be wrong.
Back of a napkin calculation: i looked at a few belden cables, the dcr is 8 or 9 ohms per 100m.
Let's say its a 200m run, with 5 amps. After some reasonable rounding, thats 20 ohms x 5^2 amps 500W!
Did i get that right? Can't be.
The guy who told me the story is dead now so I can't ask specifics. He told me the story >10 years ago so details are gone. It is possible that it was armored or shielded cable(s) that were bonded to ground at each end.
In any case specifics are not important, I was just giving a concrete example to "obscure path". Current flowed in unintended conductors due to a potential difference between earthing points. This is why NEC requires multiple electrodes to be bonded together.
In any case specifics are not important, I was just giving a concrete example to "obscure path". Current flowed in unintended conductors due to a potential difference between earthing points. This is why NEC requires multiple electrodes to be bonded together.
What wire did you use, and where did you get It? I am thinking of using silver wire for my amp build.I diy rca with silver wire , teflon isulate and some connectors cost me 20 times less if compare to boutique stuff.
Try & experiment : solder and enjoy
Sent from my SM-T550 using Tapatalk
If you just want to experiment check your local jewelry craft store. Ten feet of 24 gauge, dead soft 99.9 fine silver was under a dollar per foot here. Be skeptical of claims to more than four 9s unless you a NASA budget.
Is made with teflon insulated Cardas wire.
Today i can't find the same but jupiter _cotton for audio signal work too :
JUPITER Cotton-insulated Silver Hook-up Wire
Best regards
I've known AME's (what they're called in Canada - Aircraft Maintenance Engineer) that could not fix an inoperable aircraft radio over three months of trying. I'm speaking of an AME that was one of the most highly skilled people I've ever met. Same radio, same avionics, same aircraft (although see below) as one that worked perfectly without issues. Swapping the radios between the two offered no answers. Other radios (ground-to-air licensed frequencies) worked fine.
Simply having a cellphone in the cockpit can make the radio go nuts ... squealing and unintelligible. It's not as simple or as well understood as you might think. Some airplanes have electrical interference issues for their entire lifetimes. Unlike what most people believe, every single aircraft is slightly different from it's siblings.
A pilot can tell which aircraft he's flying instantly ... they all fly differently. Some are a dream to pilot, others of the exact same model and vintage you have to fight every minute, making constant corrections. They are not even as consistently made as your typical automobile. Each aircraft is basically a one-of, and that extends to their electrical systems. They didn't invent the term "gremlin" for nothing.
Comparatively speaking, we have it easy in Audio.
Source for silver wire (999, dead soft, same gauge system as AWG, priced per troy ounce but ordering can be in feet or inches)
Rio Grande dotcom [USA]
The example posted above (24GA) is $0.56/ft as of 29 Apr 2017
https://www.riogrande.com/Product/999-Fine-Silver-Round-Wire-10-Ga-Dead-Soft/105310
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