Interesting. I always though that the screen was connected at the source as that is normally the lowest impedance point.
Jan
Jan
Relevant signal carrying cables are bidirectional and symmetrical.
No current, voltage or signal carrying shielding is something else, which does not affect the main premise.
No current, voltage or signal carrying shielding is something else, which does not affect the main premise.
You can argue that the screen also carries voltage or current. Otherwise it could be removed with no effect ;-)
Jan
Jan
The ultimate shielding is all equipment cases interconnected with true XLR cables ( cable shield connected at both ends ).
Then, ground loops make no trouble.
Add RCA cables: Here comes troubles and compromises.
Then, ground loops make no trouble.
Add RCA cables: Here comes troubles and compromises.
In addition, any screen current continues within the equipment, from the XLR pin to the line cord ground. LF screen currents will take the path of lowest resistance, but as frequency goes up, the current will take the path of least impedance.
If the path includes the reference ground the amplifier is using for any of the signal chain, it can inject into the signal.
John
Not at all. Balanced cables with the shield intentionally lifted (or connected to the cold side for bal to unbal) at one end is the genesis of where cables having a “direction” came from in the first place. People get the idea that it applies to everything and can be used as a marketing ploy (including regular RCA cables) when it does not.
What about the dielectric properties of cable insulation/sleeving? There is a direction in which conductors are pulled.
Bruno covers this in one of his articles. Different colour wires can have slightly different dielectric properties due to minute die size differences. For most purposes this is 2 tenths of a gnats fart.
Different pigments can alter the permittivity of the insulation a bit. I've had other issues with the pigment colors in the past, but more for thermal conductivity and TCE. It should be child's play to maintain die size accuracy well below anything measurable via capacitance.
If the pigment changes the solidification shrinkage, that could be an issue as it would change the final dimension. But again, we're talking 2 tenths..
John
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Well sort of. Unfortunately the inline cap sensor is not going to catch everything. Had to replace something like 10,000 feet of RG6 (installed!) because an out of round roller caused a notch filter effect for some satellite channels. They carted a VNA to the customers home to confirm and then had to replace the in wall wiring after the job was finished. No one was happy.
While things like color in the insulator are issues for microwave and for specialized sensors its audio effect is really just emotional.
Not SIGNAL voltage or current.
What did you expect?
It´s cable thread, and directional to boot 😉
This is a cable thread, hence intrinsically a joke.
Sometimes it´s hard to separate jokes, nonsense posted as "scientific reality", tongue-in-cheek and plain trolling, so I guess you can forgive the confusion 😉
Amen Brother, but you know such indiscernible differences have been carried on and on for pages and pages of inane babble.
Often dwelling down to "you can´t PROVE I don´t hear differences" logical fallacy.
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As I said, 2 tenths, meaning of a gnats fart...as per billshurv.
I'm surprised the manu didn't have better control over the equipment. I assume it caused a wiggle in the core placement with respect to the shield at roller circumference pitch, that would really mess up the shield current placements, first one side of the cable, then the other..a long line of modulated capacitance and inductance. We use optical thingys (nowadays) to measure wire placement to the micron levels, I guess if the manu had a consistent tension on a length of core post foam but still in the line, they could look for foam placement assuming the tension could make the core stay straight to monitor the foam position. edit: This is based on the bad roller on the wet side of the die. If it were on the dry side, I could see it doing a positive feedback oscillation at the pitch of the distance between the die and the roller. This is probably more likely given wavelengths.
10,000 feet of RG6 in a customers home? Whoa, that is some BIG home..
I gave the installation crews special instructions for pulling LMR 240 as well as heliax.... treat the cables as if they were brake lines you are trying to bend and then pass through a tight hole where an oval cross section would catch, that way they knew that bend radius could oval the shield. They all understood that problem..
John
They call that an “impedance bump”, and you can find it with a time-domain reflectometer. Surprised the VNA wasn’t set up in that mode - could have found which offending cable and WHERE in the run it was actually located. Then all 10000 feet wouldnt need to be replaced.
An offset roller would cause bumps periodically within the cable. I'd think that would put a bump at least every meter (or half meter depending on the offending roller's diameter) or so the entire length of the production run.
John
It was the whole run and multiple customers. The VNA did not have the TDR option ($2k software update). It was not an issue below 1 GHz, just on satellite downlinks. It was very subtle. Some channels were not affected and adjacent channels just dropped out. In the custom installer world its all about how cheap they can get wire (as little as $0.10/foot back then) and checking the wire (TDR etc.) would be beyond the abilities of the installer.
Cat 5 etc. is all checked in manufacture but its not true for all coax, especially above the max rated use of the coax.
Cat 5 etc. is all checked in manufacture but its not true for all coax, especially above the max rated use of the coax.