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Tweakers' Asylum Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ. |
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In Reply to: Re: I have plenty of CD's... posted by AAA on December 26, 2004 at 06:05:02:
"Auricap" is a trade name for metallized polypropylene capacitors made by Audience. See the link to the site, which is loaded with hype for the audio properties of these capacitors. I haven't used these capacitors, so I can't speak to their audio properties.This tweak, however, places the capacitors across the AC line. The purpose is to shunt RFI/EMI present as difference-mode noise and reduce the level of it that gets into the audio component's power supply.
The relevant property of the shunting capacitor in this application would be its RF impedance, not its midrange transparency. No matter how good the dielectric material used may be at audio or radio frequencies, the geometry of the capacitor determines its parasitic inductance.
This inductance, which is present in any real capacitor, forms a resonant frequency with the capacitance. The capacitor has its lowest impedance at this resonant frequency, and then behaves like an inductor with rising impedance as the frequency increases above this self-resonance. Note that the self-resonant frequency is typically far above the audio band and does not affect the audio properties of the capacitor.
If the RFI/EMI on the power line has significant energy at frequencies above the self-resonant frequency of the capacitor, it is less than completely effective. Adding it might improve the sound, but the improvement would not be as much as if a capacitor with a higher self-resonant frequency were used.
All we have are anecdotes about how adding the Auricaps across the power line improves the performance of some audio gear. I'm not equipped to carry out the tests, but I'd like to see someone independent measure the self-resonant frequencies of the recommended Auricap and some alternatives, such as silver-mica and ceramic capacitors, as well as the X- and Y-rated caps.
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Follow Ups
- Audience Auricap hype - Al Sekela 09:11:46 12/26/04 (0)