Going Battery Powered

I like the idea of the inverter.

Like I said it all depends on the amp/hrs of the battery, for the job it’s to do, you can charge it with whatever you want, but never have it charging while your listening, defeats the whole purpose.
I have a very nice sounding MSB discrete R2R Dac that has 5 x half brick size gel batteries in it for the different power supplies in it, it charges the batteries when your not listening and disconnects the charger when listening.

Also My Lightspeed Attenuator runs on 12vdc Li-Ion batteries lasts up to 2 weeks before a recharge is needed , most of my customers buy it also as a "purest" power option, as I only supply a linear wall wart with it.
https://www.ebay.com.au/itm/US-Portable-Super-Rechargeable-Li-ion-Battery-Pack-DC-12V-6800mAh-for-CCTV-Cam/153537757150?hash=item23bf903fde:g:CSwAAOSwq7JT5MSO

Cheers George

In my experience batteries do not have good current delivery.

Someone needs to go back to school, better still, put a dead short across the terminals of a small 12v SLA battery, but get "real close" as you may not see the current arc. 🤦‍♂️ https://ibb.co/4ZwDct1

ricevs,
I'm a dummy; what does, "PPT," stuff mean? 

first,to the OP, Great! insightful question. And, in both theory and reality, yes.
now, practice is the hard part.  Back in the 80s, a friend and ex business partner suggested and ran, so "battery parties" where 8+ folks would get together and donate, for a while, car batteries so we could get + and - 48 Vdc with stupid hgih current (commenting on a sub thread above).
Sound: superb. Practicality: Zero.  But that was 40 year ago.
Today, for low power draw products, Lithium Ion batteries are a great way to go - but probably you will have to roll your own.  Charging is nto as simple as hooking p 12 (or whatever) volts.
 It is quieter. "blacker" as one put it. And more nuanced and dynamic.  Compared to a really good power supply, its very subtle. Compared ot the typical one, well.... your definition of typical may stray from mine. I'm not impressed.  Everything I build a power supply for gets way better.  Off topic note: wait for my rant on an Intel NUC as a ROON ROCK server, and the lessons in reality i learned.... but i digress.
It will be a project.  but the end goal may prove worthwhile.
G

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

jzzmusician
I'm a dummy; what does, "PPT," stuff mean?

Just another BS voodoo snake oil product like ($1) $150! ac mains fuses, but this ones a $300! contact cleaner
https://perfectpathtechnologies.com/product/total-contact/

Electronic engineers use as good if not better one for $22, but it's not got an "audio" snake oil signature to it.
https://www.ebay.com.au/itm/DeoxIT-Mini-Gold-spray-GN5MS-15-14g/401602406187?epid=6024006287&hash=item5d815e672b:g:954AAOSwgHpa28-g&frcectupt=true

Cheers George