Phil Leigh;527990 Wrote: > John - what's your view on after-market power supplies for the > SB3/Touch? > I'm pretty much convinced that there MIGHT be a very small benefit for > the SB3 s/pdif but I'm darned if I can find any benefit for the Touch > using its digital outputs...
I've measured big differences using a linear supply for the SB3, but its not in the signal coming out of the DAC or digital outs. The switcher that comes with the SB3 injects a huge amount of noise into the power cord which winds up in the other boxes in the system unless you have very good power filtration in your system. The frequencies that come out of this switcher are rather pernicious, they are low enough that most "RF" filters don't touch them and high enough that they sail right through the stray capacitances of most power supplies. This is not just conjecture, I've measured it several times with many different pieces of equipment, power bars, power filters etc. Its rather interesting that the only equipment which does a good job filtering out this noise is boxes which also have switching supplies. The switcher has filters designed to keep its own noise out of the electronics which also does a good job blocking the noise from the SB3 supply. The result of this is that the effect of the noise from the SB3 switcher in general is far more noticeable on high end gear that uses good linear supplies than it is with "consumer" gear using swithing supplies. In my system the good linear supply does make a significant difference with the SB3. With the SB3 supply even if the SB3 is not providing the signal it makes a difference, which seems a pretty good indication that its not direct signal related but some other vector. Just plugging the switcher is not enough to cause the problem, it has to have a significant load (the SB3) in order for this to be an issue. I have not tried just a resistor as a load to the switcher and see if that degrades the sound from other sources. The switcher that comes with the Touch is vastly better than the one that came with the SB3. With it I cannot hear any difference using the switcher or the linear supply. When I have the touch in the listening room I just use its own switcher. One test I have NOT done, but probably should is to use the Touch's supply with the SB3. In addition to the noise injected into the AC line there IS noise radiated from the wires and the supply box itself which can get picked up by interconnects and other boxes. My measurements show this to be significantly less importance than the power cord born noise, but its still there. If an audiophile is using unshielded interconnects (which are popular in some circles) this source of noise can wind up being significant. Th SB3 itself also radiates a lot more RF than the Touch, but thats irrespective of what power supply you use. So yep, using a linear instead of the switcher that comes with the SB3 CAN make a big difference to sound. How much is going to be quite system dependant. For some its going to make a big difference others won't hear it at all and others will be inbetween. That little switcher that comes with the SB3 is so bad that it makes my skin crawl just thinking about it. I keep one on the floor in my listening room and stomp on it everytime I go in or out. I've been trying to come up with a good use for one, such as testing the ruggedness of a sledge hammer etc. That little thing is amazingly resiliant, I have not been able to damage it yet. A 15 pound sledge hammer with a really good swing would probably do it. John S. -- JohnSwenson ------------------------------------------------------------------------ JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=76496 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
