(Virtual) Guitar Amplifier

Guitar amplifier has two main factors inside. There are preamp section and power amp section. All types of amplifier which are tube, solid state, combo, head - cabinet always have this two main sections.

Preamp receives the initial guitar signal, processes it, makes it stronger and sends it to power amplifier section. If guitar signal is connected directly to power amplifier, there will be small or even no sound can be heard from the speaker. The signal is not hot (loud) enough to be processed by the power amplifier.

Tone shaping and signal distorting are done in preamp section. Tone shaping has the same meaning with coloring which is setting the equalizer (bass, middle, treble and presence) knobs. Channels of guitar amplifier (Clean, Drive and Lead) are depend on its preamp electronic circuits. If guitar amplifier has 2 channels it means that this guitar amplifier has 2 different electronic circuits in preamp section.

Power amplifier is the last part of guitar amplifier. This section receives processed guitar signal by the preamp and then makes it hundreds times louder before it sent to the speaker. Generally, there is no additional coloring or characterizing in this section.

Virtual guitar amplifiers are usually done by simulating the preamp section of the real guitar amplifiers. It simulates the important parts of the real guitar amplifier that do the tonal work such as equalizer, distortion / tube behavior, input / output filters, etc and turn it into mathematical equations. The characteristics of power amplifier can be captured simultaneously with cabinet impulse response.