Class A Amplifiers and impedance dips

ALL amplifiers, even cheapo AB's, have more power to throw at lower impedance. Super cheap receivers, ie sony, won't work with even a 4 ohm load. The best way to explain it is it works like the output of a pump. The pump is the power supply. As you lower impedance, you make the outflow pipe bigger, and the pump gets water out more easily. The better pumps can handle pumping more water- cheaper pumps start to burn up. Really good s.s. amps can handle 1 ohm loads. Certain "8 ohm" speakers can dip down that low. Tube amps do not like low impedance, which is why you have to be careful and buy a speaker with a stable load. In the bad old days friends sold the carver "amazing loudspeaker" with impedance dips so low that it fried most amps.

chryslers_rule - You don't want the government in your stereo, do you? Class A amps run the output transistors ALL the time. This allows purity of signal. The disadvantage is the transistor that is left on all the time runs very hot. This means you have to have BIG heat sinks and can't run as much current through the transistor. Class AB amps use a pair of output transistors running in tandem. A turns on, B turns off. B turns on, A turns off. The advantage is you can cool off B while A is running, so you can run B at higher levels while it is on. You don't need the huge metal cooling fins (heat sinks). This means more watts at a cheaper price. The disadvantage is the switching distortion incurred flipping back and forth. As computer technology became cheap and plentiful this has become much less of a problem, because the switching is more precise. Ask morbius for a second opinion. And tell him to WATCH OUT FOR THE ID!