Acoustic guitars and their various musical relatives can be traced back thousands of years, but the idea of a guitar using electric currents to amplify its sound had to wait until the 1930s to start to take root. Necessity was, perhaps, the mother of invention here, as the volume of the guitar, used previously in blues and jazz, could not compete with the new sounds of the big band and the shriek of brass instruments. Early experiments with simply adding microphones to guitars had only limited success, partly due to the quality of the tone and partly because of the feedback that could occur as soon as a reasonable volume was reached. The breakthrough came when Les Paul, a jazz guitarist, successfully experimented with a magnetic pickup system that could convert the vibrations of the strings to an electrical signal to be amplified and sent to a speaker. Soon, guitarists started adding pickups to their hollow-bodied guitars, but in fact there was no need for an electric guitar to have a hollow body, as the pickups could detect very subtle vibrations and amplify them anyway. Before long, Fender, Rickenbacker and, of course, Gibson were producing solid-bodied electric guitars.