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 giutar 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.