Yesterday I wrote that the power coming into your stereo system is every bit as important as the bits of analog or digital that are used to manipulate it into music. What I failed to mention is that what comes out of your wall to feed your equipment is actually useless! Indeed our stereo systems have no use for what comes out of the wall, yet without it we have nothing.
Weird, eh? You probably guessed where I am going with this. What comes out of your wall is AC and what your equipment needs is DC. So why do we get what we don’t want, how is it converted and at what cost to the sanctity of our high-end systems do we pay for this travesty? Let’s spend a bit of time with this and I’ll do my best to keep it interesting for you. It’s important.
AC power already has one of the elements we need to make music – moving electricity – yet when we get that electricity it’s moving in the wrong way to make music.
Our AC power moves back and fourth between positive and negative (like flipping a battery around) at 50 or 60 times a second depending on what country we live in. If you plug your loudspeaker directly into your home’s AC power socket you’ll get a nice steady tone out of it – although please don’t try this at home because most woofers aren’t robust enough to handle that much power – you would wind up with a smouldering piece of metal. Years ago when JBL used to make quality hi-fi products (that’s another story), they had a woofer that was so strong they tested them by doing exactly that – plugging them straight into the wall socket for a few seconds. That would have been quite loud!
I thought it might be fun to start at the beginning and learn just what AC power is, why it exists and why we don’t use anything else even when AC isn’t what we want. I’d also like to touch on an often misunderstood concept in high-end audio, that of the designer’s dilemma: is an amplifier the all important element fed by a power supply, or is the power supply the all important element feeding an amplifier? The distinction might seem trivial but I assure you it is anything but that.
Tomorrow we start to get an understanding of what it is and answer some of the fundamental questions. Next we’ll move on to a story of one of the greatest battles of all time and then wrap our new found understanding into the next problem inherent in everyone’s system and what we can do about it.