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I bought a used Elpac power supply to use with my Squeezebox since it's linear supply is supposedly better than the factory supplied switching power supply (note I don't know what the difference between switching and linear supplies are so don't know about advantages or disadvantages of each). I can't try it yet b/c I have the plug reterminated to fit the Squeezebox.Each can deliver what is needed in terms of volts and amps, so why is the linear supply supposedly better? IOW - How can it improve the sound quality of the device it is powering? Does the linear supply inject less (or none) noise into the component (or other components via back feeding)? Can I liken this to amplifier power in terms of RMS vs. peak power? Is the switching supply likely to not be able to deliver a constant voltage and amprege while the linear supply can? Would appreciate a simple laymens explanation. Thanks!
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Well, a lot of people tend to underestimate the importance of the power supply, because it's "Not in the signal path". Well, technically, it isn't, BUT . . . it IS the path!In other words, any noise in that power supply is going to make some kind of AC signal, however faint. You want to get as pure a DC as possible, which should measure as a pure straight line on a scope.
While getting it to go away totally may be impossible, even with batteries, a good power supply can be so quiet that it effectively doesn't affect the signal at all.
Try this sometime: no signal applied, crank everything all the way up. If you can hear anything, even if you have to get up close (make sure no one else is gonna press "play" on anything!), most of what you will be hearing is your power supply, as well as any noise it picks up from the "outside world".
Hope this helps, my brain is tired.
Hmm, that line up top could be kind of catchy, I might have to hang on to it for when/if I get my company off the ground: "The power supply isn't in the signal path, it IS the path!"
Nite every one,
Power amp power supplies also have an important role to play in amp stability and output impedance control, but that is a little more technical.Your question regarding switching versus linear power supplies is a good one. Switching supplies use very rapid switching, in the radio frequency range, to allow them to get away with smaller and cheaper magnetic components. Along with the specified DC, they produce residues of the internal switching frequency as noise. This noise gets onto your household AC wiring through the AC input to the switching supply. From there it goes to your other audio components and degrades the audio performance.
Linear supplies can also be noisy if the rectifiers cause the power transformers to ring, but this is easier to fix than the RF noise from switching supplies.
Many non-audio appliances have switching supplies these days, since they are cheaper and lighter than linear supplies. These appliances also degrade the performance of audio systems, even if they are on different AC circuits.
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