Jan, It is more likely that the noise you are hearing is coming from the magnetics rather than from any capacitors. There are planar transformers in the switching power supply and the Ethernet interface. Sometimes the transformer core material has a natural frequency harmonic in the audio band. You could try potting the transformers to reduce or eliminate the noise.
Jeff > Hi. > > I've been using net4801s and a net5501 as broadband routers for use at > home for some time now. > > Generally great and fun. There's just one down side: these boxes are not > completely silent, in that they make a strange hissing sound while > they're doing actual work (like routing network traffic). I therefore > can't really use these boxes for workloads that pump a constant or > pulsating amount of traffic through them because the hissing (even > though its really not that loud) would drive me bonkers. > > So here's a sanity check: are my boxes the only-ones doing this? > > What's causing it? I thought it was the CPU but given that the 4801s and > the 5501 have a different CPU (OK so they're both Geodes) I was thinking > perhaps not? > > Is there anything I can do to stop the hissing? Of course I'm aware of > the wondrous effects of noise insulation afforded by putting boxes in a > different room than where I am; not what I'm asking. > > Thanks, Jan > _______________________________________________ Soekris-tech mailing list [email protected] http://lists.soekris.com/mailman/listinfo/soekris-tech
