"PexiBass V20" is a high-quality, custom-made tube amplifier for musical instruments, guitar, bass and harmonica. It brings together the best of both worlds: high-gain British (Plexiglass JTM) and American "clean" (Bassman) with a lot of "headroom" (space for musical dynamics). This project has the pretension to meet the demand of the great majority of musicians, with pre-amplifier circuit based on the two greatest classics of all time for guitar, bass and harmonica harmonica. "PlexiBass V20" has 20W of valve power, in a "single ended" configuration, this chameleon goes to the stage and studio, and yet maintains the extreme simplicity of the circuit and can be assembled by beginner assembler craftsmen.