If you were to research back through the original McGraw-Hill Electronics professional magazine about the year 1971 or 1972, you'll find a power amp design that I've never seen anywhere else. Rather than a complementary-symmetry output, it used a pair of 2N3055 to yank the speakers around. It developed the driving signal by placing a pair of 10 ohm resistors in series with the power supply leads of a 741 op amp (king of the world op amp in 1972), ground the output through a load resistor and taking the IR signal developed by the supply leads to drive the remaining circuitry. It was a direct-coupled, 100W RMS amp and the danged thing was good from DC to 200KHz, only because there was a snubber in the output line or it would have gone even higher than that.
When I was stationed at the USNSGA at Sabana Seca, Puerto Rico, CTMCS Malcolm Empey built one and we tested it out in the maintenance shop with a function generator, the amp driving a 5W speaker. Watching a speaker cone "breathe" when driven by a 2 Hz signal was amazing back then and when we got done, the speaker's yoke was too hot to touch and the voice coil was wrecked. I need to research that design out. I have the skem, but I'm not sure if there wasn't a mistake in the hand transposition, because my attempt at cloning back in 1974 failed miserably and I've never gone back to the project for some reason. I need to as it would still be quite fun in this day and age of Class D amps.
Dean