The Maxim datasheets all claim that the parts will run from a 10 VDC supply. For example, the MAX9704 (the 10 watt stereo part) will run from 10-24 VDC. Oddly, the higher output wattage part, the MAX9708 (21 watts per channel at 8 ohms) has a maximum of 18VDC for the supply.
Assuming this is correct, I can run the 10W MAX9704 part directly from my input voltage of 12-24VDC. The others, I would use a 12 volt regulator because of the upper limit is lower than 24 VDC.
Is there much perceived difference ("loudness") between 10, 15, and 20 watts? Other than the audio amplifier, is there any difference between an 8 ohm 15 watt speaker and a 4 ohm 15 watt speaker?
Thanks,
Dale