A cheap SMPS usually does put out a lot of noise, both on its output and on its input.
CE (and, to a lesser extent, FCC) regulations place limits on: - the amount of energy radiated off the system as a whole between frequencies of 30MHz and 1GHz; - the amount of noise conducted back up the mains supply, between frequencies of 150kHz and 30MHz. So, it's perfectly possible for a PSU to be fully compliant to those standards, but to put out a lot of hash on the mains supply right through the audio band, and also to produce large amounts of noise on the DC output provided it doesn't radiate too much over 30MHz. The idea that it won't produce much noise because it's efficient is, I'm afraid, rubbish. The efficiency just means it won't get all that hot - nothing more. If it causes sound quality problems with the SB3, it'll be because of low impedance, high frequency switching noise on the DC output, which is hard to filter and therefore makes it through to the internal power rails. -- AndyC_772 ------------------------------------------------------------------------ AndyC_772's Profile: http://forums.slimdevices.com/member.php?userid=10472 View this thread: http://forums.slimdevices.com/showthread.php?t=34749 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
