Wow! What was so confusing earlier is so clear now. Thanks for the explanations guys. I think I'm going to purchase a emotiva amplifier in the near future. Any thoughts on this company? How much power should I be looking for for a 5-7 channel amp? I want it to last for years and not have to worry about upgrading again.
An amplifier takes the source signal and turns it into a speaker signal.
A pre-amplifier takes the source signal and either:
a) turns it down a little with resistive elements (attenuates).
b) turns it up a little with small amplification elements (gain) - but, remains a source signal.
c) doesn't disturb the signal at all (unity gain).
d) often acts as a switching device between multiple source signals. A gate-keeper for the amplifier.
I was going to add to my post, but I guess I can't edit. @HIFiSid can you help?
Here's an illustration that may help.