Paul McGowan: I am often asked why power supplies make a difference in audio electronics. For, after all, it’s the power supply and it is not in the signal path. Being outside the signal path suggests that a well designed power supply should be sonically invisible, as if it were not even there, yet the opposite is true.
Perhaps we’ll spend some time exploring this very subject.
Let’s start with the obvious. The power supply for a power generating product, like a power amplifier, makes a sonic difference for a number of reasons. Chief among them is the ability to deliver enough power to not starve the loudspeaker’s needs. When the music gets loud power is required to drive the loudspeaker and that power comes from the amp’s supply. It would then seem obvious that a supply that’s less than adequate would have some sonic issues if it simply ran out of power. Clipping, strained sound, etc. would be rather obvious effects.
But what happens if you compare the sonic results of two power supplies of equal strength driving the same amplifier? Would they sound the same if their topology was very different and neither caused any obvious signal damage? The short answer is no, they would not and the reason they would not is fundamental to answering our question of how something not in the signal path could affect the sound your hear.
Tomorrow we’ll start to take a look at this intriguing question.