cliveb;171172 Wrote: > > FWIW, my hypothesis is that the reason the SMPS sounds worse in some > people's systems is not because of the actual supply to the Squeezebox, > but because it sprays all sorts of nasty RFI around the place, which > could affect the analogue circuitry in other components. Some systems > will be more vulnerable to this than others. But remember this is just > a hypothesis to try and fit various people's findings.
I believe that this is also the case. I've measured the EMI from the wall wart and it is not pretty. It gets into everything. When I have the SB3 out on my bench it significantly increases the noise floor of my HP spectrum analyzer, even when I don't have anything hooked up to it. I was running the SB3 into a power amp and kept on seeing all this RF and couldn't figure out where it was coming from, then I unplugged the probe and it stayed! I unplugged the wall wart and it went back down to normal. But it is a really nice way to find out how well a piece of gear rejects RF! Some equiptment I can see the RF getting amplified all over the place inside and others could cae less. One amp even went into severe oscillations when the wall wart was plugged in. I've done an experiment with several peoples systems where they are listening to the system and I plug the wall wart in without them knowing and in all but one case I got a "what the hell just happened" reaction. I get pretty much the same result whether its plugged into the SB3 or not. Wrapping the PS, cord and SB3 in foil gets rid of the problem, so I'm pretty confident its an EMI issue. But it is rather difficult to see the display when its wrapped in foil. How much a system is susceptible to this does seem to depend on the equipment in use. Tube systems tend to not like it more than SS systems, but thats not a hard and fast rule, the one where I got the biggest reaction to the "test" was an all SS system. My system tends to be on the lower sensitivity side but I can still definately hear it, but its not nearly as big an effect as in some systems. Even if you can't hear the difference between a linear and the wall wart I still don't like the idea of using the wall wart, it just bothers me to be spraying EMI all over the place, you might later on get a piece of equipment that IS sensitive to it and never know its full potential. John S. -- JohnSwenson ------------------------------------------------------------------------ JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=31758 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
