I'm talking in the context of guitar amps, but I assume that this question is relevant for any type of audio amplifier.
Very often in amplifier schematics I see two stages of amplification — first, the signal is amplified a smaller amount by a preamp circuit and then amplified again by a power amp circuit.
This seems redundant to me. What's the point in amplifying a signal in two small steps rather than just one greater-gain amplification?
My first thought was: does this multi-stage amplification help to reduce unwanted noise from the signal? But the more I think about that, the less it makes sense, since surely the second stage would be amplifying any noise as well.