I measured the output of the stock wall wart PSU with an O'Scope this morning.
Whether the pictures in the enjoythemusic.com review represent the outputs of *typical* switching PSU's or not I can't say, but they certainly do *NOT* represent the output of the PSU that came with my Squeezebox. The scope I used was a Tektronix 2213A, the probe was a Tektronix P6130. With the scope in DC coupled mode I was only able to discern approximately 100mv of ripple, there was a very small amount of switching noise present. It was difficult to measure the switching noise in DC coupled mode since it was obviously riding on the +5VDC. The smallest voltage range usable was 500mv/Div, attempting to use a more sensitive range resulted in the o'scope trace being off scale. In AC coupled mode I was able to discern about 80mv of ripple. There was definitely switching noise artifacts present in the signal, these were generally on the order of approximately 30mv. 100mv of ripple works out to 2% of rated voltage. It should be noted that the signal observed in the AC coupled mode was affected by the coupling circuitry of the o'scope. It would have been preferable to use the DC coupling mode, but this was not possible. It should also be noted that the measurements I took were of an un-loaded PSU. I have a photo of the AC coupled trace which I will post when I get home this evening. The conclusion I arrived at was this: there is a small amount of ripple and switching noise on the output of the stock wall wart, but it is not even close to any of the signals depicted in the enjoythemusic.com review. The photos in the review were of the output of a Squeezebox 2. I don't know if the Squeezebox 2 came with a different PSU, but the signal photographed by BoulderCable did not look remotely similar to what I observed. -- nelamvr6 ------------------------------------------------------------------------ nelamvr6's Profile: http://forums.slimdevices.com/member.php?userid=3113 View this thread: http://forums.slimdevices.com/showthread.php?t=21175 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
