What's The Big Deal About Battery Powered Preamps?

Mitch4t

The main reason for a battery power preamp is to avoid any type of contamination that occurs with ac power. I'm sure you have noticed all of the different types of line conditioners and power cords that are on the market. With batteries, you avoid all of that. Also, the preamp runs on DC which eliminates the need to rectify.

Jfrech,

Your comment about improved prat with a battery preamp is very interesting. If anything, I would have thought it would be the opposite. If that's the case, I might try one myself.

Batteries can have a lot of "juice". Actually, that's where they're best. How many amps is your car battery rated for?

Had the original battery preamp, the Mission 776 from the 80's, and it was more dynamic and without the bloated bass of the dual chasis SFL2. Preferred the Mission. If it had XLR, might still be using it. Now, gone passive with no power at all. With a healthy source, there's no shortage of dynamics with that either.

If the preamp is otherwise well designed, a battery power supply lends a very low noise floor. The importance of low noise at the preamp stage cannot be overstated - as noise and distortion are additive, and the amplifier magnifies the input signal from the preamp, preamp noise and source noise are particularly deleterious.

For preamp I agree it's great. The downside is when the battery runs out meaning that you should have either an extra battery just like for your DeWalt cordless drill or wall socket option.
I DIY-upgrade now my 30y old Classe 30 to work off the 24V automotive battery. A power 2-way switch will power up the battery when preamp is OFF and power ON safe battery charger. Contrary when the preamp is ON the safe battery charger is OFF. For listening session upto the whole day and night of charging will be plenty enough to run on pure battery power.

Mitch, good question. I'm running a dac and integrated amp off a 12v car battery and the experience has been nothing short of an audio revelation. My source is a laptop which I run off the battery so the whole system is off the grid.
The amp can only output about 10 to 20 watts from the 12v, but the power delivery is huge since there's a huge power reserve in the big battery. The sound is crystal clear with huge authority & control. You need a pretty efficient speaker. My speaker are horns. You could bring in another 12 volt battery and double the voltage to 24 which would double wattage to 20-40 watts, and on & on...
The dc power is immediate - there's no ac to dc conversion so there's no need for the big and noisy transformers (this is where much time and money goes to developing hifi gear-quieting the power delivery through the transformers). I'm not too knowledgeable on the technical side of this and hopefully another member can comment on the mechanics. I'd recommend giving it a try.