I'm tinkering with a monolithic integrated circuit power amplifier chip -
TDA2040. It is designed to deliver 20 watts (.5% THD) into a 4 Ohm load
with a +/- 16 volt supply. Peak output current is 4 amps.

If I run the IC at +/- 10 volts. Is it okay reduce the impedance of the load
as long as I'm within the peak current or is there another limitation? The
manufacturer specs allow for a supply voltage as low as +/- 2.5 volts
(obviously with a much reduced output swing).

Another way of saying this is what other limitations are there preventing
one from using a lower impedance load considering the and the output
transistors can handle the current and dissipation. Let's consider the
supply is not a limitation either.

Thanks, John