It turns out the world of low-voltage audio is a lot of fun, and I’d like to start sharing some of my journey through it. I suspect everyone has a different reason for entering this world, lending each story a different color and set of priorities. Mine goes something like this.
For a while now, I’ve been designing audio circuits for mostly high-end consumer audio products (e.g., see this). This has afforded me the opportunity to select tried-and-true medium to high-voltage supplies as needed in the pursuit of perfect performance. Like a lot of people serving in this rarefied domain, I developed a mostly reflexive reaction to low-voltage stuff. I mean, it’s probably OK for casual listening, but real audio only happens with real voltage, right?
One of the ways you begin to question a belief is when holding that belief starts becoming inconvenient. And that is what has happened to me.
I’m currently working on a high-performance audio project that for not very interesting reasons I can’t tell you about needs to be powered from a wall-wart. In the past, I might have considered using a wall-mounted AC transformer like one of these, put a basic rectification circuit inside the product’s box to generate a raw bipolar supply, and then regulated that down to +/-15VDC or whatever. But wall-mounted transformers of this sort now run afoul of consumer market efficiency requirements for wall-mounted power supplies. An additional constraint on this project is that the wall-wart provide a maximum of 9 volts.
This means, in short, that the project needs to embrace a switching main power source, which lends this story an additional layer.
Like all my audio work, I am 100% committed to making this project have the best possible performance subject to its constraints. There are lots of interesting and potentially interrelated questions that are going to come up, and in this "Joys of Low-Voltage Audio" series I hope to share with you some of the insights I gain.