Going Battery Powered


I have a number of components that run off of 12V DC power. This includes my DAC, preamp, tube buffer, etc. I’m looking into powering them with batteries instead of 120V AC power supplies. Does anyone have any input on if this is worth my time? Seems like DC power is the cleanest power you can get in this situation. I’ve heard batteries can have reduced dynamics but I plan on using as big of a battery as is reasonable, most likely a large sealed AGM type battery. Do I need power supplies/voltage regulators if I use a large battery and only power low draw components (no power amps); e.g. the max amp draw is probably around 1-2 amps, if that. If I do, does anyone have a link to a design for the power supply/voltage regulator? Thank you.
mkgus

Showing 1 response by terry9

I use batteries for my DIY phono/pre. It’s black, and I would not go back. I use 120VAC power for the DIY amplifiers with very fast and very quiet bridge rectifiers and LCLCLC filter circuit. A hundred kilograms of inductors and a Farad of capacitance. Not cheap.

An AC power supply typically is made from a step-down transformer and a rectifier, at which point the power peaks at nearly 1.5x the voltage of the transformer's secondary, and sags to 0. 120 times per second. Obviously this is pretty lousy power, so it must be smoothed with reactance (inductance and capacitance).

The best AC power supplies follow the rectifier with an inductor (L) followed by a capacitor (C), with two or three stages of LC. These serve to smooth the voltage variation, known as the ’ripple voltage’. Lower is better.

It costs an arm and a leg to get ripple voltage down to 1ppm, which corresponds to .012mV. Not even the worst battery is that noisy. Which is why it’s better to power directly from batteries than to regenerate and then go through the transformer and rectifier and LC filters to achieve an inferior result.

The downside is that batteries store energy and can deliver it pretty fast, so it’s wise to have them fused. And have quality connectors that can’t be pulled apart by accident.

Just my views. YMMV