2 amps with identical RMS ratings will probably have similar drive characteristics into a resistor.
As soon as you start driving complex loads with current ahead or behind voltage, that's where you'll start hearing significant differences.
Amps which can tolerate such complex loads will have more apparent power.
As a test you could find 2 different speakers of similar sensitivity..make them 91 to 93db rating. Also, 1 speaker should be a fairly benign load and the other as wretched as you can find. Huge phase angles and large impedence swings.
Try a couple or more amps. amp#1 should be a very high quality unit. Nearly any of the 'biggies' should work. Find another amp of similar power. This one should be of much lower quality, but similar RMS power rating. They should both play an easy load to similar loudness levels. However, when driving a difficult load, the better amp will play louder, longer without heating, and provide a much superior listening session.
As soon as you start driving complex loads with current ahead or behind voltage, that's where you'll start hearing significant differences.
Amps which can tolerate such complex loads will have more apparent power.
As a test you could find 2 different speakers of similar sensitivity..make them 91 to 93db rating. Also, 1 speaker should be a fairly benign load and the other as wretched as you can find. Huge phase angles and large impedence swings.
Try a couple or more amps. amp#1 should be a very high quality unit. Nearly any of the 'biggies' should work. Find another amp of similar power. This one should be of much lower quality, but similar RMS power rating. They should both play an easy load to similar loudness levels. However, when driving a difficult load, the better amp will play louder, longer without heating, and provide a much superior listening session.