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In Reply to: RE: RFI & EMI Question posted by rbyar on June 30, 2009 at 09:31:30
means that your AC has RF noise on it. While the specific filter inside your power conditioner appears to remove some noise, it also may limit the dynamics of your power amp.
The best thing to do is to listen carefully with it in place, and then with it removed. Try to distinguish true musical dynamic contrasts from the artifacts of the RF noise (a harsh, in-your-face quality).
Many users run their power amps directly from the wall outlet, perhaps with a parallel filter, and use conditioning or regeneration for the source and line stage components.
The basic problem with most RFI/EMI filters is that they use series inductors to block some of the noise. These series inductors also limit the AC current to the power amp.
Your options in an apartment are limited, but you can at least try turning off and unplugging the non-audio appliances in your apartment to see which of them contributes damaging levels of RF noise. Any appliance with more than an on/off switch these days has a little computer inside and is likely generating RF noise as long as it is plugged in. Video gear, computer equipment, microwave ovens, etc., are all likely sources of noise. Adding RFI/EMI filters to these can reduce the amount of the noise that gets back into your audio system.
What has been your experience with quantifying noise introduced into the mains by compact fluorescent lights (CFL)?
A friend brought a Graham-Stetzer meter which supposedly measures microtransients in the electrical system. We measured an outlet using a lamp with a CFL bulb and got a reading of 124. Switching the bulb to an incandescent got a reading of 36.
Any thoughts?
Cogito Ergo Credo
Any fluorescent lamp needs a ballast to function with AC line power. The newer ballasts are electronic and I would expect them to make RF noise at some level. The electric arc inside the tube is also a noise source. However, I've not noticed noise on AM radios near lamps with compact fluorescent bulbs installed.
Your question inspired me to hold a portable AM radio right next to a CFL. I could hear a slight hiss with the lamp on that went away when I switched it off. Other non-audio appliances seem to be worse. The fluorescent display on my Wadia 861 makes about as much noise.
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