Pre-amplifier and Amplifier difference?

[myheart22]

Hi!

Goodevening, I am a 3rd yr ECE student from the Philippines.

Until now I am confused with the difference between Preamplifier and Amplifier.
We had a design proposal on Audio Power Amplifier but then, our work is always been trashed by our professor because I can't answer him what is the purpose of the preamp if there is already a power amplifier. :/

Moreover, can you please tell me what is the advantage of having a preamp. And what may be the output if I didn't include the preamp on our design.

Any kind of help will be much appreciated. Thank you!

 

[Resqueline]

Hi, and welcome to the forums.

I haven't seen your design proposal but I'll nevertheless try to help you get into the thinking of the professor (as I see it).

What are the definitions of amp's, power-amp's, and pre-amp's? What would their respective input & output signal ranges & impedances be (V/A/W/Ohms)?
Rough terms suffices, like high, low, mV, V, etc.

 

[Laplace]

Would you place the most attention to low-noise electronic design in the pre-amp or the power-amp? Why?

Would the volume control, equalization, and tone controls be placed at the input to the pre-amp or at the input to the power-amp?

What is the voltage gain and current gain of each amplifier? Would the pre-amp be able to drive large speaker coils?

Can you put the pre-amp and the power-amp on the same board/case and just call it the amplifier?