Audiofile9 has it right. I'd like to add a few more footnotes.
Slew rate is the slope of the curve if you change the input of an amp instantaneously from one voltage to another. Its how fast the amp is and its ability to track a complex signal. A very low slew rate would act as a low pass filter ie only let the low freqencies through. A trumpet signal for instance is made up of wave forms that are close to square waves. Square waves (in Fourier analysis..don't ask) are made up of a combination of infinitly high frequencies so a slow slew rate amp would cut off the high frequency components of the trumpet's harmonics.
Negative feedback was used in excess in the 1960s and 1970s to give amps IM and THD distortions measurements of 0.0001%. These numbers seem very nice but you will notice that today's best amps have IM and THD measurements of 0.1% so they are 1000 time more distortion. Well a guy by the name of Otella discovered TIM transient IM distortion caused by feedback. Its a distortion that can't be measured by putting steady state sin waves through the amp but rather music or more complicated wave forms. Seems that a amp, any amp, has a delay from the time a signal is seen at its input to the time you see it at its output (not slew rate delay) This delay when feed back to the input spears the signal and adds a distortion that was not accounted for the the 60-70s but is now well understood. So modern amps brag about low feedback design.
Slew rate is the slope of the curve if you change the input of an amp instantaneously from one voltage to another. Its how fast the amp is and its ability to track a complex signal. A very low slew rate would act as a low pass filter ie only let the low freqencies through. A trumpet signal for instance is made up of wave forms that are close to square waves. Square waves (in Fourier analysis..don't ask) are made up of a combination of infinitly high frequencies so a slow slew rate amp would cut off the high frequency components of the trumpet's harmonics.
Negative feedback was used in excess in the 1960s and 1970s to give amps IM and THD distortions measurements of 0.0001%. These numbers seem very nice but you will notice that today's best amps have IM and THD measurements of 0.1% so they are 1000 time more distortion. Well a guy by the name of Otella discovered TIM transient IM distortion caused by feedback. Its a distortion that can't be measured by putting steady state sin waves through the amp but rather music or more complicated wave forms. Seems that a amp, any amp, has a delay from the time a signal is seen at its input to the time you see it at its output (not slew rate delay) This delay when feed back to the input spears the signal and adds a distortion that was not accounted for the the 60-70s but is now well understood. So modern amps brag about low feedback design.