| Electronics > Beginners |
| Cable shielding audiophool or facts? |
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| CatalinaWOW:
Just remember, the OP is self identified as limited knowledge and is reporting what an audiophool has told him about something he heard is a wonderful technique. Why would you expect the drawing OP did to have any resemblance to the original cable? Take a low information content source and pass it through two low bandwidth channels and then spend a lot of energy debunking the output. Makes sense to me. |
| coppercone2:
Ok so is it any different then what people to do to fudge usb grounds? How electrically similar is this to having two shielded cables going between two boxes but only connected to one box and connected to the other box by a small capacitor? It kinda sounds like it will resonate. You are linking the grounds through a rudimentary distributed high pass filter. The nondistributed model is cable L and R to set impedance then pass capacitance into a lower impedance since the chassis impedance should be lower then the cable unless its some shady ass glued conductive plastic etc. But its distributed. In my opinion it smells like a last ditch bs hack but idk for sure. By controlling the amount of nesting eg protrusion you set the filter parameter impedance and coupling too. Not sure why to do this. The energy might go through your ground instead. |
| Richard Crowley:
--- Quote from: coppercone2 on November 16, 2018, 05:27:39 pm ---Ok so is it any different then what people to do to fudge usb grounds? --- End quote --- USB uses a balanced, differential data signal pair (D+ and D-) The signal is NOT ground-referenced, so (theoretically) it does not require a ground connection. This is exactly like balanced-pair audio connections shown in my illustration where the cable is "2-conductor shielded cable" --- Quote ---How electrically similar is this to having two shielded cables going between two boxes but only connected to one box and connected to the other box by a small capacitor? --- End quote --- That is called "telescoping shield" at least in audio circles. It is illustrated in the illustration as # 1, 2, 5, 6, 7, 8, 11, 12, 13, 14, 17, 18, 23, and 24 Connecting a small capacitor (active at RF but not audio frequencies) at the unterminated end is also regular practice, especially in conditions where places where RFI is a problem. (Like broadcast transmitter sites, etc.) --- Quote ---It kinda sounds like it will resonate. You are linking the grounds through a rudimentary distributed high pass filter But its distributed. --- End quote --- No, it is not any kind of filter. Draw out your proposed circuit with the "filter" and show us. Words mean nothing at this point in the discussion. It is monumental BS. |
| coppercone2:
Your shield impedance depends on the capacitance so its a high pass filter with impedance set by l of the lenght if you imagine it as nondistributed. By shady usb ground i meant when people put like a 5k resistor between usb grounds. This is the same thing but you are putting a freq dep element c rather then r |
| coppercone2:
Untelescope them in your mind till the overlap is almost nothing and you will see it as two inductors connected by a cap |
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