When Les Paul invented the first solid body electric guitar in the 1950's - blues musicians immediately embraced the new contraption. Since electric guitars require an amplifier (amp) to produce the sound, it is an easy matter to electronically alter the signal to change the sound. They recognized the possibilities of being able to make funky sounds with it. Click for Electric Guitar Types information. One of the first "effects" to be invented was the Reverb effect, essentially an electronic echo that diminishes rapidly. Many guitar amps today have reverb built in, it is a simple and elegant sound effect that adds a warmth to the guitar sound. Effects for electric guitars are usually created by plug-in devices, these usually take the form of a "Pedal" (as they are stomped on to activate the effect, or control it). Rock and metal guitarists often use several effects pedals connected in a daisy-chain. Newer models of effects pedals are computerized (digital) and a single device can create all possible variations of effects by itself.

All present western music (rock, jazz, R&B, rap, etc) has evolved from blues, and the ability to alter the sounds of an electric guitar have been passed on to each new genre. Heavy metal, for example, almost exclusively uses the Distortion effect with electric guitars. The distortion effect does exactly what its name suggests, it distorts the original guitar sound and produces a completely new sound - bordering on screeching. Jimi Hendrix has created mind bending wails from his guitar with distortion. Many amps today have distortion effects built in, it is a very popular effect used in rock and blues music. While many variations of distortion exist, most are are "Gain" control effects. Two controls, "Pre-Gain" and "Post-Gain", alter the sound on the pre and post edge of the sound wave. This can create sounds ranging from a flat "thunk" (bluesy), to a screeching "wail" (metal).

The Wah Wah effect was made popular during the sixties by bands such as Cream. The Wah Wah effect is activated by the guitarist's foot (by rocking the effect pedal), and alters the tone of the sound (going from low treble to high treble) - this creates a voice-like wah-wah-wah effect. New digital wah wah effects devices also have "Auto Wah", in which no pedal pressing is required - the computer in the device automatically varies the sound for you. Some popular rock songs use a wah wah pedal, but it is kept stationary in halfway position - this makes a unique funky sound. Many other effects are also available; such as producing an acoustic guitar sound from an electric guitar pickups, signal duplication (sounds like two guitars are playing), rotating speaker modelling (mimics rotating cone speakers used by some musicians), and many more effects.