| PookyNMR wrote on Tue, 21 December 2004 05:53 |
| danlavry wrote on Mon, 20 December 2004 13:45 |
As far as I know, the dielectric constant effects only the electric field, therefor the capacitance. It does not impact the magnetic field strength. I do not see how it can impact noise. Where is that article?
Regards
Dan Lavry
|
Dan,
Found the article. It is by Joseph DiBenedetto. He said:
Along with twisting and shielding, the dielectric is an instrumental factor in the performance of the cable. The dielectric in the cable is the insulation that coats each conductor, electrically separating the conductors from each other and the shield. When the signal travels down the copper conductor, it will actually be ?absorbed? through the dielectric and into the shield. This occurs to a greater effect at higher frequencies. Typically, you should look for a dielectric with a low k constant. ?For the dielectric, you should choose a solid polyethylene, foam polyethylene or foam polypropylene compound,? Fehl explained. ?Stay away from PVC-type compounds because the dielectric constant is higher. The lower the dielectric constant, the lower the high-frequency attenuation.?
Apparently, I got my info mixed up with other info. The importance of the constant had to do with high frequency attenuation.
Nathan
|
OK. That makes sense. Noise reduction? NO. High frequency characteristics? Yes. I can appreciate the comments for high frequencies, way above the audio range. I do not see it as a factor for audio. The higher dielectric constant yields more capacity, and we already talked about capacitance, and how too much capacity in the presence of high impedance may cause a low pass filter effect. This is not normally the case. But the material properties Fhel is talking about is at much higher frequencies, not audio.
Regards
Dan Lavry
Author
Topic: Technical question that everyone hates (audio cables) (Read 16755 times)