[RFI] Belkin PureAV™ Home Theater Battery Back up

Jim Brown jim at audiosystemsgroup.com
Fri Dec 4 09:58:03 PST 2009

On Fri, 04 Dec 2009 08:44:28 -0500, kd4e wrote:

>Are they really RFI-clean or do they only address line noise?

Hi Doc,

As you probably know, I work in pro audio. The real engineers 
among us get quite a laugh out of the technical claims made from 
the purveyors of audio accessories to "clean up that nasty AC 
line" to make audio gear sound better. 

I'd guess that this product is a standard backup power supply with 
a simple power line RFI filter. It probably also has MOVs in it. I 
would guess that it doesn't MAKE RF noise in standby mode, but I'd 
bet that it DOES when it's regenerating AC during a power failure. 

When I'm specifying systems for public buildings (theaters, 
churches, stadiums, etc) where things need to work with flaky 
power, I specify the combination of a SurgeX suppressor (for 
lightning protections) and a backup on DSP-based equipment so that 
it doesn't lose its brains or have to reboot with a power 
interruption. If you've got an extra $600 laying around, you could 
do that for your home stereo. 

If you simply want to do some RF filtering, look for RF line 
filters from mfrs like Corcom and Delta. They cost a LOT less. The 
SurgeX units also include very good RF line filters. See the RFI 
tutorial on my website for photos of some filters and a discussion 
of how they work. 



Jim Brown K9YC

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