[Karls48 (Karl)]

Hi Acropolite. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o:p></o:p>
It is true that web cameras and sound cards works very good in extremely noisy environment, but they have been designed for it. We got Spectrum analyzer at work and I have seen noise presented on various switchers, ranging from tens of KHz to few MHz. Cheep imported switchers are usually worst. This noise is very difficult to get rid of because it is “common mode” meaning it is same on both outputs, positive and negative. Capacitor across the output will do nothing. The noise can be lowered by common mode choke, but not completely eliminated. Well designed and expensive switchers are pretty quite, but never as good as linear power supplies. Installers of security cameras almost never use switcher for camera installations for this reason. Even if switcher are more compact, cheaper and run cooler the linear power supply of same power output.<o:p></o:p>
Karl<o:p></o:p>