⚠️ Tube amps contain lethal voltages (400V+ DC) even when unplugged

⚠️ Never operate a tube amp without a speaker load (transformer can arc and fail).

⚠️ Solid-state amps usually have lower voltages (<50V) but still can have large filter caps – discharge before repair.

Your search will likely yield two types of PDFs: one for valve (tube) amplifiers and one for solid-state. However, the basic theory overlaps significantly.

Common clipping arrangements:

This is where the magic happens. The preamp boosts your weak guitar signal (millivolts) to a stronger level (volts). It also contains the tone stack (Bass, Mid, Treble controls) and the gain control. In a tube amp, this stage is responsible for creating warm overdrive when pushed.

| Component | Schematic Symbol | Function in Guitar Amp | |-----------|----------------|------------------------| | Resistor | Zigzag line | Sets bias, voltage division, gain | | Capacitor | Two parallel lines | Blocks DC, passes AC (coupling, filtering, tone) | | Inductor (rare) | Coiled loops | Used in some equalizers | | Diode | Triangle with line | Rectification, clipping (distortion) | | Triode Tube | Heated cathode, grid, plate | Voltage amplification (preamp) | | Pentode Tube | Similar with two extra grids | High power amplification (power amp) | | Transistor (BJT) | C, B, E pins | Solid-state amplification | | Op-Amp | Triangle with +/- inputs | Gain blocks in solid-state & pedal circuits | | Transformer | Two coils of wire | Voltage/impedance conversion, galvanic isolation |