questions

1. Slew Rate - How fast one can sell off a slew of unwanted equipment.

2. Damping Factor - How much of a cup of coffee one can spill into a power amp before it goes up in smoke.

3. Negative Feedback - What I'm gonna get for injecting a little levity into this forum. ;>) Don

Good one Elgordo. Let me take a crack at it with the little knowledge I have.

Slew Rate: how fast an amplifier can swing it's voltage, measured in Volts / millisecond or something like that. I think amps with "higher" slew rates sound more analytical.

Damping Factor: determined by the amplifier's output impedence, may relate to their ability to "control" a speaker. I think amps with higher Damping have tighter bass.

Negative Feedback: some of the amp's output is "fed" back to the input, but in reverse phase. The effect being that it forms a self-controlling loop. If the amp's output goes too high, more of it comes back to CUT the input, thereby bringing the output back down.

I hope that made sense, and I hope that is somewhat accurate - no engineer here. Now, the REAL question is, do any of these really say anything about the SOUND of the amplifier? I personally don't think so. I think great numbers are easily acheivable by any manufacturer, but not all high-end amp makers even care about the numbers. Personally, I like tube amps, which often have reasonable SlewRates, poor DampingFactor, and NO negative feedback. Go figure.

i got a kick out of that elgordo!nice to see people with humor.thanks for the input everybody,i really apreciate it!dave...

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.