Most common: (Treble, Middle, Bass)

Using larger tubes (6L6, EL34, 6V6) or high-power transistors, this section multiplies the current to drive the speaker. Key concepts here include:

Block DC voltage while letting AC (your guitar signal) pass. They are also the heart of Tone Stacks (Bass/Middle/Treble) by filtering specific frequencies.

Control the flow of current and set "bias" (the operating point) for tubes or transistors.

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: Essential for calculating how much power an amplifier delivers to a speaker. Impedance Matching