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Originally Posted by Tirefryr
That would explain why I do not get a reading, but if that is the case, aren't you inducing noise when using a grounded shield? They go through the trouble to isolate the signal ground from the chassis, so why re-introduce one?
I don't know much about electronics, so help me out here. I know when I built motor control panels and Cell phone buildings, there were certain shielded cables that did not get grounded on either end for fear of inducing noise back through the shield. I do know you have to isolate AC from DC and high from low voltage.
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This helps my case further actually. Remember in the picture I showed that the Knu rca shield is not grounded(meaning the shield is not connected to that neg on connector). Well If Knu made an external ground where a wire runs out of the cable and you have to screw it to a piece of metal, then more noise can be induced, but by just using the ground on connector your risk factor is far less.
Why do you think that the Pioneer 880 was having grounding issues people saw, the resistors inside that was trying to keep noise down and isolated burnt out(btw that only happens if someone plugs their rca's in hot ) and to "fix" it all they did was Reground that outer ring of the rca connector.
oh about that cellphone building thing: this might help explain why grounded shields are bad at times:
Cable shielding and groundloops
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or cable shield connections there are four options, with advantages and disadvantages:
1. Shield grounded at both ends: Good r.f. shielding but susceptible to ground loop currents that can be VERY large - up to at least 100 A in bad cases.
2. Shield grounded at both end, with large-area parallel bonding wire: Good at r.f. and now the ground current flows mainly through the bonding wire, but the intense magnetic field that may result is not good news. The bonding wire size needs to be, for example, 10 mm^2.
3. Shield grounded at one end only: No ground current but not good at radio frequencies for which the cable is more than 1/8 wavelength long. R.F. interference may actually be worse than for an unshielded cable.
4. Shield grounded at the sending end and grounded through a capacitor (may be two in parallel, for effectiveness from about 100 kHz up to 1 GHz and beyond) at the receiving end: Good at r.f. if the capacitor type and positioning are correctly-designed, and no low-frequency ground current. One capacitor needs to be of the type with an integral spark- gap so that it is not damaged by transient high-voltage spikes that may be induced on to the shield.
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