I would like to use car amp to push the home speaker.

How do you convert car amp's DC to AC power line for home use?

Thanks, if anyone knows how to do it.

You can buy a voltage convertor, but it will cost almost as much as simply buying a sub amp from Parts Express.

How much is it?

don't do it.you'll no doubt induce dc hum.
you can turn up the volume to overcome it but it will still be there

Why it will induce hum?

well, i think one is gonna be the ac to dc inverter although there are chokes available to filter this out probably a quality test bench power supply would have good clean power out this alone would probably be above the cost of a good home amp,and then another could be a "floating ground" i came across this on an amp in my truck,turned out to be a really stupid problem(little tear in the shield of my sub amp cable) but the term just makes me think that electronics like a good ground and i would think that intermixing different (car and home) would not be a good idea if any level of quality is to be maintained.although i do remember using the speaker level out on my sound-design receiver to feed a pyramid eq/booster(battery charger powered) to power 12" stromberg carlsen speakers 20 years ago.

car amps dont typically perform very well out of their environment for lots of reasons... youd be better off selling the car amp, and buying a cheapo receiver to do the amplification...

Never!! Receiver sucks!!

not quite as hard as a car amp sucks though.

I don't think it's worth it to hook up all the car stuff as a HT. A converter that could supply decent power and do it cleanly would cost too much. I've looked at doing this both ways before. However, I am curious as to what you have.