Paul McGowan writes: In a recent post we learned that the size of a switching power supply is so much smaller than a conventional linear supply because the power transformer shrunk an order of several magnitudes – and it did this because we’ve managed to chop up the incoming AC into little tiny on/off bits through the use of an electronic switch.
Because our incoming power is now switching on and off thousands of times a second, rather than 50 or 60 times a second as it does in our homes, our transformer can shrink to the size of a matchbox or a pack of playing cards. Pretty cool stuff.
But there’s a problem with switching on and off that quickly – noise and fairly ugly harmonics. So while a switching power supply has a number of advantages over a linear supply (which we’ll cover in a bit) it has some fairly major drawbacks when it comes to treating our power lines with respect – fact is it’s got no respect!
So we find ourselves in a place where use of a SMPS is actually worse for our systems and can cause everything else in the high-end audio chain to sound a lot worse. This is one of the primary reasons why SMPS get a bad rap in high end audio and people stay away from them. Devices that use SMPS are computers, projectors, TV’s and now most modern consumer electronics – and these all use pretty noisy supplies. Products like the Power Plant can help a great deal when you want to isolate your system from these nasty beasts – passive power conditioners not so much.
But all this bad news isn’t always true and, in fact, the opposite can be achieved with a SMPS. I’ll give you an example – our friend Jeff Rowland in Colorado Springs makes some really gorgeous and great sounding high-end audio products admired the world over – and most of Jeff’s products run on SMPS. Jeff was one of the brave pioneers in our industry who realized that properly implemented and designed, these SMPS could far outperform not only the duties of the power supply but how it interacted with our line voltage.
Indeed, a well designed SMPS is far quieter and gentler on the home’s AC power than any linear power supply ever thought to be.