Originally Posted by palchiu
Is this a good idea?
Use two car battery makes a 24V to amp?
If it's possible, hope can gets more clean sound.
While it's possible to do that, you have to make sure that the car batteries aren't putting out more than what the opamps could tolerate. Also, even car batteries will eventually become discharged, and they do not like to be completely and repeatedly discharged (will shorten the lifespan). So, you will have to put the batteries on a charger when you aren't using the amp. To me that seems like a major inconvenience.
I also don't think a car battery will really offer "cleaner sound" than a good regulated power supply. A car battery actually could be noisier than a regulated power supply. While I haven't done any noise testing of a car battery myself, I point you to the following article about voltage regulator noise. The part of interest is at the end of Page 4, where a lead-acid battery is tested for noise. Car batteries are of the lead-acid variety, and this test shows worse noise performance than a regulated power supply under load:http://www.tnt-audio.com/clinica/reg..._noise1_e.html