Car Battery as Power Source

If you want a true sinusoidal wave, use something like the Xantrex. You are going to have to use a substantial bank of batteries to supply anything over 1000W and you also have to worry about a battery charger (although you can get an inverter and charger in one unit).

Fully concur with Seandtaylor99's entire post.

So, what if I used one of these Pure Sine Wave inverters?

Also, my monoblock amps require 75Watts ea. to operate. So, they don't require much power. Maybe a couple of these inverters with a couple of Optima batteries and I'm in business huh?

Although, from a practical point of view( as opposed to my theoretical and just bored POV) I probably won't realize a material difference in sound if my current electricity is relatively clean when I listen true?

Does anyone know if the PS Audio P300 etc. convert AC to DC and back to AC again within their units?

Here are the inverters I was mentioning:

Inverers

Unless someone has tried it with your equipment I think you'll have to try it, though I wouldn't be surprised if it sounded worse, not better.

Some powerline filters do regenerate the AC. They tend to be the more expensive ones, as they are really no more than a very high current output power amp. You're effectively using a large power amp to power your system.