I have had some experience with the little wall wart that comes with the SB3. As many of you know I have modified my SB3 to take its "I2S" (which is really left justified) data signals into my DAC and feed the DAC's clock into the SB3. The other day I had it out on the bench trying out some changes to the output stage and was seeing all kinds of RF on the output stage.
After a lot of debugging it turned out to be the wall wart that came with the SB3. I didn't bother to take the linear supply out to the garrage so just used the wall-wart. It was radiating large amounts of RF every where. Even with the SB3 disconnected from the DAC It still had the same amount of RF in the DAC. It also stayed the same with the SB3 disconnected from the supply. With the wall-wart unplugged the RF goes away. With the SB3 connected to the linear supply there is a very tiny amount of RF in the DAC but WAY less. I think this is coming from the unshielded SB3. As far as I can tell that supply is just spraying RF all over the place. Its a bit interesting because it comes in bursts. It looks like the RF is happening when the supply is conducting from the wall voltage so we get tone bursts. Under load the bursts get longer (the supply is conducting over a longer period of the AC cycle) but the intensity of the RF is the same. So there is a pretty high probability that this RF is getting picked up by other components in a system whach may be causing significant differences in sound. This can also help explain to some degree why ome peoples systems have a larger change when changing supplies than others. It would depend very much on how the components and wiring respond to RF. Some will do a better job of rejecting the RF than others. When I first got an SB3 I had to switch to shielded interconects, it was unlistenable with the unshielded ones I had been using. At the time I thought it was the SB3 itself that was radiating the RF, now I realize it was the wall-wart that was doing the damage. One good thing that the experience produced is that I "hardened" my DAC significantly to outside RF, even with the wall-wart the amount of RF in the DAC is a lot less than it used to be. Just doing that has significantly improved the sound of my system. John S. -- JohnSwenson ------------------------------------------------------------------------ JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=29633 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
