Monoprice 611502 Mini Headphone Amplifier for Guitar,"Tube Overdrive" As a musician you know you need to practice regularly to hone your skills and learn new songs For those times when quiet is required you can both practice and hear the amplified output from your instrument using this Mini Headphone Amplifier for Guitar from Monoprice! This amplifier is designed to provide amplification to the output of instrument level devices such as electric guitars and bass guitars