JohnSwenson;528305 Wrote: > 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. John - thanks for taking the time to type all of this - really fascinating stuff. This explains a lot:
1) Why I could never detect/measure any audible differences with the different supplies - I was measuring the SB3 in isolation, so there were no other vectors. 2) When doing listening tests, my system has a very high-quality switching supply in the pre-amp which would filter out any crap coming back in via the mains through that vector 3) I only use screened cables (I did once have an NVA amp that came with unscreened cables - it also came with a self-destruct feature!) 4) I use a symmetrical choke-based mains filter for all of my "switching" supplies (router, USB disk, HDMI Switch box, SB3/Touch) that will stop some crud coming back onto the mains from those devices. -- Phil Leigh You want to see the signal path BEFORE it gets onto a CD/vinyl...it ain't what you'd call minimal... SB Touch Beta (wired) - TACT 2.2X (Linear PSU) + Good Vibrations S/W - MF Triplethreat(Audiocom full mods) - Linn 5103 - Aktiv 5.1 system (6x LK140's, ESPEK/TRIKAN/KATAN/SEIZMIK 10.5), Townsend Supertweeters, Blue Jeans Digital,Kimber Speaker & Chord Interconnect cables Kitchen Boom, Outdoors: SB Radio ------------------------------------------------------------------------ Phil Leigh's Profile: http://forums.slimdevices.com/member.php?userid=85 View this thread: http://forums.slimdevices.com/showthread.php?t=76496 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/audiophiles
