Joys of Low-Voltage Audio: a journey begins

high-voltage lines

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.

I’ve been designing audio circuits for high-end consumer audio products for a while now (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 needs to be powered from a wall-wart. In the past, I would 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 almost all wall-mounted transformers of this sort now run afoul of consumer market efficiency requirements. And an additional constraint in the case of this particular project is that the wall-wart provide a maximum of 9 volts.

This leaves me little choice apart from using a switching 5 to 9VDC main power source for this project. Hello, low-voltage audio.

Like all my audio work, I am completely committed to making this project have the best possible performance subject to its constraints. There are lots of interesting and potentially interrelated questions that have come up in my design process. In this "Joys of Low-Voltage Audio" series I hope to share with you some of the insights I’ve gained.

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