What is a preamp and poweramp used for?

[FrehleyFan]

What exactly does the preamp and power amp do? I have a vague idea but would like someone else to help me understand.

[Meole]

The pre amp colours the sound, bass, treble, gain, etc..
The power amp increases the signal from the preamp to make it louder.

[FrehleyFan]

Thankyou for the information Meole! I appreceate it alot. If anyone else has anything to offer I'd love to hear you too!

[tluxtele]

meole is somewhat right but i would add that the power amp also adds color. depending on how you have it biased, what tubes you're using, etc.

the main difference is power tubes need a high voltage signal to amplify. the signal that comes from your guitar is not high voltage. so how will the power amp amplify it? the signal goes through a series of gain stages. the preamp tubes are designed specifically to increase the voltage of the signal. let's take the orange ad15

your guitar signal comes in to your amp. it runs through the first gain stage (1/2 of the 12ax7 furthest from the power tubes). oh, btw, a 12ax7 basically has two tubes in it (it is two triodes) which is why it goes through half of the tube.

ok, then the output of that tube is hooked up to a volume pot (labled gain on the amp). this controls how much of the signal from the first gainstage goes to the second gain stage.

the signal now runs through the second gain stage. from the second gain stage it goes through the tone stack.

from the tone stack it goes to the phase inverter. the signal swing is 360*. since the power amp is a push pull power amp where one tube takes 180* of the signal and the other tube takes the other 180* of the signal, you need something to split the signal up. the phase inverter is not really pre amp or power amp. but the signal is amplified and split there.

then the signal is fed to the power amp tubes. by now, you have enough voltage to be amplifed by the power tubes.

does this make since?

clean as a whistle