12v linear power supply

@audioman58  Is not wrong.  For speakers the driver to speaker cost is at least 10:1, a major reason why some turn to in-house drivers. It's not just engineering but cost.

I've seen some brands like Rega pump up the ratio of the electronics even higher, say 20 or 30 to 1.  I'm thinking of a headphone amp I took apart once.  Ugh.

Don’t use analogies, define your terms and explain the engineering. Switch mode power supplies create a lot of high frequency noise - its well known, its a problem too.

Funny coming from someone claiming to be an engineer.  You claim you want rigor and then immediately come out with broad, general brushstrokes.

A well designed SMPS can have extremely low output impedance and noise, far lower noise than a LPS, if well designed.

It's a lot easier to design a low noise SMPS than a low noise Class D amplifier so a lot of the problems associated with Class D are easier to deal with in a power supply.  Unlike a Class D amp which has to output AC, for instance, an SMPS only has to put out 1 constant voltage.